- 1 day ago
The new Norton debuted a full line of new bikes recently as parent company TVS finally pulled back the curtain after 5 years of work. Cycle World's Kevin Cameron and Mark Hoyer start about 125 years earlier, at the beginning of the company and its reputation for remarkable singles and following racing success. Isle of Man TT! Norton Manx! Up through Commando and the demise of the company in the 1970s. Join us for the ride and then visit cycleworld.com to see the new Nortons on cycleworld.com/eicma landing page.
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Listen on Spotify: https://open.spotify.com/show/6CLI74xvMBFLDOC1tQaCOQ
Read more from Cycle World: https://www.cycleworld.com/
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SportsTranscript
00:00:00Welcome back to the Cycle World podcast. If you're already a listener and if this is your first one, welcome.
00:00:05I am Mark Hoyer, editor-in-chief of Cycle World, and I'm with Kevin Cameron, our longtime technical editor and legendary transportation thinker.
00:00:15We always have a good time.
00:00:19Someone asked me about the origin of the podcast, like why did we start doing it?
00:00:23And I said it's because typically I have a flannel shirt and I have ridiculous headphones and that's what we do.
00:00:29We start podcasts when you have big headphones and a flannel.
00:00:34But in fact, Kevin and I would talk on the phone every week or more, sometimes less, and we would talk about lots of these kinds of topics and new things would come out.
00:00:45We would talk about them and I thought to myself, well, what if we just formalize this very slightly and figured out the technical difficulties of mounting a camera on a tripod and plugging it into a laptop?
00:00:57And here we are.
00:00:59Quickly approaching the 100th episode, thank you for the support, everyone, and also our sponsors who have helped us out, Mecham Auctions for one.
00:01:09They'll be back, we'll be doing a Mecham Auctions podcast on interesting motorcycles at the Las Vegas Motorcycle Auction happening in January.
00:01:18So stay tuned for stuff about that.
00:01:20But right now, before I start talking about all the troubles I'm having on my Ford 460 ignition system, because it's really on my mind, let's talk about Norton motorcycles.
00:01:34So we're going to talk about kind of the history of Norton motorcycles, where they came from, and also what Kevin would describe as the great leap forward, which I'll let him sort of kick us off there.
00:01:46All right, well, in our time, we're accustomed to what I would call the racing engine progression,
00:01:58which starts out with a mildly sporty street bike with a bore to stroke ratio of 1.3.
00:02:11Meaning the bore is bigger than the stroke by a factor of 30%, so 1.3.
00:02:19And the people have added in World Superbike and in the various national superbike series such as AMA used to run.
00:02:27And before long, the manufacturers are saying, we're not winning.
00:02:33We know our motorcycle is the best one, and we certainly want to sell it.
00:02:39So the engineers say, well, we can rev it up.
00:02:42We'll see what we can do with cam profiles.
00:02:46And they do that for a while, and you can spend a lot of money with cam profiles.
00:02:53Oh, here's one, gives tremendous power, but it breaks valve springs.
00:02:58That is a story many times told.
00:03:02Vigorous acceleration, really send that valve open, and then at the right moment, close it,
00:03:11just as the last whiff of intake velocity is crowding through the valve, which is almost on its seat.
00:03:20And I like to think about that.
00:03:22It's like people trying to make it into one of those closed sails.
00:03:26They're rushing for the door when the bell rings or the clacks and sounds.
00:03:32Yeah, so we got some interesting feedback from a viewer on YouTube when we were talking about exhaust systems, I think.
00:03:39And one of the comments was someone who was involved in drag racing.
00:03:42We were talking about blowdown.
00:03:43And that's what you're talking about here is it's, you know, the exhaust is rushing out.
00:03:47So you're hundreds of PSI, hundred and something PSI after the combustion event.
00:03:53And you'd use the energy to push the piston down.
00:03:55And then you open the exhaust valve and poof, goes auspuff, as the Germans say.
00:04:00Auspuff.
00:04:01It goes out, and then it, you know, the waves go through the exhaust.
00:04:06And then you're hoping that there is that negative pressure that comes in and pulls more mixture in, as Kevin's describing.
00:04:13The drag race guys, this fellow said that at some very late timing, like, they want to open the exhaust valve, but it's still 1500 PSI in the cylinder.
00:04:27I thought, well, that's a different universe, isn't it?
00:04:30We don't have that going on at all.
00:04:32Because the way they draw the curve of pressure versus volume, the amount wasted by opening the exhaust port is just this little shading, like a little bit of territory down at the toe of the curve where the pressure is low and there's not a lot of energy.
00:04:52So the notion of trying to push the exhaust valve open at 1500 PSI, that is a big load on the cam.
00:05:02So, and there's been more than one engine that has had all kinds of failures because of the trouble in a supercharged engine of shoving the exhaust valve open against the considerable residual pressure in the cylinder.
00:05:18Well, how many times have you seen on drag race runs where the blower and the top of the engine just shoots skyward?
00:05:25Yes.
00:05:26Don't want.
00:05:28But it is spectacular.
00:05:29Anyway, in that early time, the superbike era, they next say, oh, we'll shorten the stroke and that way the piston acceleration will decrease and we'll be able to rev up without reciprocating parts problems like piston cracking.
00:05:50Piston cracking is serious once you get into racing because you've got aluminum, which is prone to fatigue failure, and you've got temperature.
00:06:02And when you raise the temperature, all the little molecules are...
00:06:05They have almost enough energy to let go of their bonds one to another, ultimately initiating a crack.
00:06:15Or at least sponging a bit.
00:06:18Yep, yep.
00:06:20But Norton followed a very different path because they faced a different limit.
00:06:30Their crankshafts, when they started going to the TT and trying to win it, let's say starting after World War I, 1920,
00:06:42they had five-piece crankshafts that were pressed, tapered, keyed, and nutted together.
00:06:54It was a sort of a cross your fingers, folks, because we don't want any of these many joints, four of them, to slip.
00:07:03And indeed, when Honda got to the end of their classic era of racing in the later 1960s,
00:07:11their big 500, the RC-181 that was ridden by Mike Halewood, did have some crankshaft slippage problems.
00:07:20But what this effectively did was RPM was rising fairly briskly in 1920, 25.
00:07:28By the time they got to 1930, they're running at 5,000 RPM.
00:07:33When they got to 6,000 or 6,500, maybe we ought to cool it a little bit there.
00:07:43So what we see in the case of Norton's development is instead of bigger bores for bigger valves,
00:07:52shorter strokes for reduced piston acceleration,
00:07:56because these modern industrial motorcycle manufacturers don't think too much about retooling
00:08:05for a completely different engine.
00:08:08At least they didn't in that superbike era.
00:08:11So suddenly they're kind of RPM limited.
00:08:16Here is the basic fact.
00:08:18In 1908, when Pa Norton, as he is often referred to,
00:08:26decided to give his big single a 79 by 100 millimeter boren stroke,
00:08:34how could he know that that boren stroke would remain constant,
00:08:40including the racing engines, the racing singles,
00:08:45which were so refined and so developed by Joe Craig, who was their racing director,
00:08:52that that boren stroke would remain unchanged until 1951.
00:08:58Well, what did they do?
00:09:01They discovered the miracle of valve overlap, for one thing.
00:09:07They discovered late intake valve closure.
00:09:12They discovered, oh, this fuel doesn't knock like last year's fuel.
00:09:17We should raise the compression ratio.
00:09:20So as fuel octane was improving in the late 20s, compression ratio was going up, up, up.
00:09:27And the rule of thumb from the engineers is that peak combustion pressure is like 100 times the compression ratio.
00:09:38So if you're starting out in 1920 with four and a half to one, five to one,
00:09:44that's not a lot of combustion pressure.
00:09:46Yes, the pistons are receiving some energy, but not as much as they could if it was 10 to one.
00:09:57So compression ratio is rising.
00:10:02And in those early days, as I said, RPM is rising.
00:10:06So it's performing more power producing cycles per minute.
00:10:11That's RPM, pretty much.
00:10:14Of course, you have to divide it by two because a four-stroke requires two revolutions to complete its cycle.
00:10:21But what they were doing was they were refining everything about that 79 by 100 engine.
00:10:28In 1927 or so, Harry Westlake in England wondered why the three Sunbeam race engines that he'd bought
00:10:38all had different horsepower, one had 25, one had 26, one of them had 29.
00:10:47Why can't they all be like that?
00:10:51So he thought about it and he decided maybe it's harder in some engines for the airflow
00:10:59to get into the combustion chamber, to get to fill the cylinder.
00:11:03So he built this thing to measure airflow and son of a gun.
00:11:11It was true.
00:11:13The airflow capacity of the poor performing engines, the 25 and the 26 horsepower ones,
00:11:20was notably less than in the 29 horsepower case.
00:11:26So he had a business.
00:11:28I'll fix your lousy engine and make it outstanding.
00:11:31And about the same time at the U.S. Army's Air Development Center, McCook Field in Dayton, Ohio,
00:11:43near where the Air Force Museum now is, at Wright Field.
00:11:50It's out of town, but it's nearby.
00:11:51They started measuring engine airflow.
00:11:55So suddenly they could actually make changes, find out what they were going to do,
00:12:05and guide their work by means of actual measurements rather than, well, this port looks pretty good.
00:12:14So, you know, the parts, the parts cannon, you know, when you're trying to diagnose a problem,
00:12:20you know, there's a lot of ways of doing that.
00:12:22You might buy an oscilloscope and check for the square waves of the pickup or, you know,
00:12:27for the ignitions breaking up or, you know, you just buy a lot of parts and keep bolting them on.
00:12:32Try A, try B.
00:12:34It's great to have actual data and measure things before you make decisions.
00:12:38Look at that.
00:12:38Science.
00:12:38So they are, they gave up side valve in a side valve engine.
00:12:47The valves are beside the cylinder with their stems pointing down.
00:12:51So the air goes up to the valve and out of the valve and across a little compartment where the valves are
00:12:59and then down into the cylinder.
00:13:01So the air is, if it doesn't have a map, it could get lost.
00:13:05Side valves did not have good airflow.
00:13:08But overhead valve engines, hmm, how are we going to lubricate it?
00:13:14I know, oil can.
00:13:17And the early overhead valve engines from all those British manufacturers, that's what you did.
00:13:24You brought an oil can or a dab of grease.
00:13:28And where did the oil go when it flew off of those busy rocker arms?
00:13:35On your pants, on your pants, on your shirt.
00:13:38That wasn't popular.
00:13:41So all these changes are boosting power.
00:13:44And soon, an iron head and an iron cylinder were running too hot.
00:13:51They ran into the dreaded, in the earliest days, they called it misfiring, meaning it's not firing the way we want it to.
00:14:01It wasn't misfiring like intermittent firing.
00:14:06It was bad firing.
00:14:08So they realized that the engine wasn't cooling very well, so they made the head out of bronze.
00:14:18Hard enough to seat valves on.
00:14:21About double the conductivity, heat conductivity.
00:14:26Lower operating temperature.
00:14:27That era didn't last long at all.
00:14:31It was a nice looking cylinder head, though.
00:14:33Oh, lovely thing to see those.
00:14:36Bronze heads, they're gorgeous.
00:14:38They are.
00:14:39They've got one on a 40 Triumph bronze head, racing head of the day.
00:14:43Great stuff.
00:14:44It's like when you get a really high-quality valve spring, and you can just see the sheen and the nickel in it.
00:14:53Yes.
00:14:54It's just, it's so good.
00:14:56You can just.
00:14:56You won't see it at the Guggenheim.
00:15:00But it is art.
00:15:04Yeah.
00:15:04Because it inspires emotion.
00:15:06Anyway, they're, meanwhile, they're sitting there at 6,500 RPM or so, and they're doing all these changes, and the overhead valve engine riders in the TT had to carry a couple of push rods down their boot top on one side, and a valve depressor down the top of the other boot.
00:15:30Because, clang, a push rod would pop out, no problem, stop, pull out a fresh push rod, stick your tool in, good as new, push off, we're racing again.
00:15:45And Norton decided with their Model 18, which was a push rod and rocker.
00:15:57Really great motorcycle.
00:15:58I rode a 46.
00:16:00Really, just.
00:16:01Single cylinder.
00:16:03Yeah.
00:16:03Why won't it win the TT?
00:16:06So, they're asking around, and somebody said, why don't you call Walter Moore?
00:16:12He kind of, that's how he makes his living.
00:16:15He goes to these different companies and says, oh, you've got a gearbox problem, I'll design one for you.
00:16:19Here, how about that?
00:16:21That'll be 1995.
00:16:24And so, they called him in, and he said, what would you win with?
00:16:29Look at, your motorcycle's a mess.
00:16:31It has a rim, a brake block and dummy rim brake on the rear.
00:16:39It has this flopping single plane bicycle frame where the stays going to the rear axle are attached to the seat post.
00:16:50So, it is relatively easy for the rear wheel assembly to swing from side to side, merrily steering the motorcycle without your permission.
00:17:01Now, in those days, the riders called this poor steering.
00:17:07So, they said, Walt, you're hired.
00:17:19And so, Walter Moore goes shopping, and he comes back with 40 Model T brake drums.
00:17:27And he directs the prototype guys how to lace these things, modify them to lace into a Norton rear wheel.
00:17:38Wire spokes.
00:17:39What else?
00:17:40And he's looking at the frame, and he's thinking to himself, I'm going to run the rear axle stays on the bottom forward under the engine into a Y-shaped casting.
00:17:58The Epsilon frame, if you will, and this Y-shaped thing in the front, it will join to a single down tube coming from the steering head.
00:18:09And it put a stop to that self-steering.
00:18:13And one rider said, just that difference in the frame is worth 10 miles an hour to me.
00:18:22And because think of what sabotage it is if your motorcycle has one idea about where you should go, and you have another.
00:18:34And every corner, you're having to have this discussion over again.
00:18:39Let's quiet down that action.
00:18:41So, I used to think that it was Howard Davies, the HRD, in Vincent HRD.
00:18:50Howard Davies, in 1924, produced a frame like this.
00:18:54But Walter Moore had already built one for the Model 18.
00:18:59And they were off and running.
00:19:02They began to win races.
00:19:05And at last, they had some guidance.
00:19:09Because this was an era in which the tendency was, let's swoop up the engine.
00:19:16Who needs brakes?
00:19:17Who needs a chassis?
00:19:19Who needs reliability?
00:19:22Well, we all do.
00:19:24So, this thing was successful.
00:19:30Mind you, still 79 by 100.
00:19:32And in 1927, Walter Moore designed a single overhead camshaft head for the Model 18 bottom end.
00:19:42A CS-1.
00:19:43Yes, the CS-1, camshaft one.
00:19:45And this was intended to solve the toss pushrods, unintended excessive valve train clearance, that is valve float, problems.
00:20:03Because it eliminates the rocker arm.
00:20:05It eliminates the pushrod.
00:20:07So, the spring is only having to move the valve, one-third of the spring, the retainer.
00:20:16Instead of the entire pushrod.
00:20:18Instead of all that apparatus.
00:20:20Now, I don't want to step on the toes of people who cherish and worship at the feet of pushrod and rocker engines.
00:20:32Some wonderful things have been accomplished in this way, not only in an engineering sense, but also in persuading the public that this is cool, which is contrary to fact.
00:20:48Yeah, I mean, two-valve pushrod, two of the greatest examples would be, for me, Norton Commando.
00:20:56Yep.
00:20:56Incredible combustion chamber and great flow, 28 degrees of spark, maximum spark lead, which is meaning that combustion chamber is working great.
00:21:07And the Harley-Davidson XR750, a paragon of flow and swirl and filling.
00:21:14Yes, because it never stopped being developed.
00:21:18One of the things that's not obvious when you look at the old XR is that during its lifetime, the stiffness of its valve train was doubled.
00:21:31And this is the key to making pushrods and rockers work quite well.
00:21:37Anyway, there's an old story about how Moore, with the one overhead cam engine that was finished, had to rent a tugboat for the price of a new motorcycle to take him across the Isle of Man.
00:21:55And Stanley Wood says, what baloney, I had that engine in Germany.
00:22:00It was running all over the place.
00:22:03That's just a, that's public relations.
00:22:05What fun.
00:22:08Nonsense was going on, even, even in back in 1926, 27.
00:22:15So I'm going to leave off with, with the development of the Norton single cylinder racer, because it went from single overhead cam to double overhead cam, still 79 by 100.
00:22:28Until 1951, which is when suddenly the coming of the feather bed frame designed by the two Irishmen using actual experimentation to develop the frame.
00:22:49They weren't stylists.
00:22:50They weren't stylists.
00:22:55Suddenly, with this new frame and with the 50 odd horsepower that this long string of development had produced, it was competitive.
00:23:06It was more than competitive with Jalera's inline four cylinder.
00:23:15Pretty good stuff, I'd say.
00:23:16So, for four years, they changed, they enlarged the bore and shortened the stroke every year on the factory engines.
00:23:27They were, they were getting sincere.
00:23:29They were, far seeing persons could imagine the superbike future.
00:23:36So, now we have to step off of this trail and take up a completely different orientation to motorcycle development, which is, when World War II ended, Britain, having participated in two world wars, had, in, in the scorekeeping sense, won.
00:24:04In World War I and World War II, but in the financial sense, they lost their fundament.
00:24:12They were deeply in debt in 1945, and the government was just scrabbling around.
00:24:19What are we going, what can we export to get hard currency?
00:24:23Turns out, England's two big exports at that time were whiskey and motorcycles.
00:24:32Cue the wild one.
00:24:37Yeah, you got it.
00:24:39And so, the, the Board of Trade, which supposedly has it, at that time, had its own security and intelligence service that was very good at finding out things about German manufacturing or Italian manufacturing, etc.
00:24:58They announced that British motorcycles going back into production for the civilian market, 70% of production had to be exported.
00:25:12Well, Norton were famous for making singles.
00:25:18That's what they had made the whole time.
00:25:20Their whole history was singles.
00:25:24Some of them were sporting.
00:25:26Most of them were just thudding, get-to-work specials.
00:25:29So, that wasn't going to sell in the USA.
00:25:37Remember, when World War II ended, people in the USA had nothing to buy during four years.
00:25:46So, they kept that money.
00:25:48They stored it away.
00:25:50No products, no spending.
00:25:51When the war ended, they wanted to have fun.
00:25:56They wanted to buy houses and cars and motorcycles.
00:26:02So, that meant Norton needed a twin.
00:26:06Because Edward Turner, in 1937, had designed the Triumph Speed Twin, which was the 500, making 26 horsepower.
00:26:14Had a different sound.
00:26:16It accelerated well.
00:26:17Well, Americans were accustomed to a different sort of motorcycle, quite portly, making a similar amount of power to the English product, but having to move a lot more avoir du poids.
00:26:34The motorcycles were chubby.
00:26:37So, English motorcycles, particularly the Triumph Twins, sold well in the U.S.
00:26:43Norton needed some of that action.
00:26:45You made a great point in a recent podcast about Honda, the CB350, that's been posted not long ago, about winning the war in English factories and technology.
00:27:02Oh, that was Hopwood made that point.
00:27:03Yeah.
00:27:04Yeah.
00:27:05And that Japan, it's hard to call it an advantage, but Japan and Germany both had nothing to start.
00:27:14They were flat.
00:27:15You know, they had a lot of old stuff.
00:27:16Yeah.
00:27:16I mean, think about the amount of bombing that took place in Germany.
00:27:20Both nations suffered the loss of their 66 largest cities.
00:27:26Yeah.
00:27:26I mean, just tragic waste.
00:27:29Yeah.
00:27:29But, as you said, and as Hopwood said, you know, they're starting, they're not shackled by what already was.
00:27:39They're allowed to say, rethink, how do we do this?
00:27:43Start afresh.
00:27:44Yeah.
00:27:45Brand new.
00:27:46And he was thinking of Germany, but it actually turned out that it was Japan that was the danger.
00:27:51So, what Hopwood was saying was, hmm, the Germans have nothing.
00:27:58When they reenter commerce, they're going to do it with the latest designs and the latest manufacturing technology.
00:28:07And Hopwood had good reason to know that Norton, Triumph, BSA, et cetera, were still not using actual production lines.
00:28:20It was informal manufacturing.
00:28:24What will happen if Germany manufactures motorcycles on production lines, motorcycles with up-to-date design?
00:28:35Well, they'll wipe us out.
00:28:37We need a new product across the board from 125 to 750.
00:28:45Well, of course, that wasn't going to go over with management because stockholders want their share.
00:28:58And so, that meant no reinvestment, no production lines, no new manufacturing equipment.
00:29:06We know how to do it anyway.
00:29:08We'll just carry on regardless.
00:29:10And so, Hopwood wrote a book about this called Whatever Happened to the British Motorcycle Industry.
00:29:21But he has his critics who say that he was utterly unable to deal with criticism, that he had ideas that he was unable to let go of.
00:29:34And isn't this the way of it?
00:29:39If someone asks your wife about you, is she going to report the same qualities and lackings that you would?
00:29:53No, everyone's got an opinion.
00:29:55And so, I'm just mentioning this because we can't take everything that Hopwood says as gospel, but he was someone who recorded his thoughts on the matter.
00:30:08So, we consider them here.
00:30:09Anyway, Norton's got to come up with a twin.
00:30:13And this fellow Hopwood had been sharpening pencils for Edward Turner for years.
00:30:23That cannot have been easy because neither man was an easy personality to get on with.
00:30:35But they bring him in and they're building a new factory and they're, I think he's working in a hallway or in a boot closet at various times before the actual drafting apparatus and so forth appears.
00:30:53But he designs a twin for Norton to export.
00:30:58And the central thrust of this design was not so much manufacturing convenience, like the Japanese engines open like a clam and all the parts are set into their little places.
00:31:19All the little grooves fit the little snap rings and the ball bearings and everything just clicks into place.
00:31:24What he was concerned about was what he had learned while he was at Triumph because the Speed Twin was not strictly the first of its kind.
00:31:41There had been a motorcycle called the 6-1 before it.
00:31:46But when Turner arrived, he said, get rid of that, scrap all that stuff.
00:31:53We're not, no, we're not doing that.
00:31:56He was brilliant at making something simple that appealed to the market.
00:32:03But if someone said, well, I'll do some calculations and come up with the diameter of valve spring wire that we'll need.
00:32:11That's for calculations?
00:32:12That's for schoolboys.
00:32:15Haven't you outgrown that?
00:32:18So any effort by Hopwood to optimize things ahead of time was opposed.
00:32:30Anyway, what Hopwood had seen was that the Triumph Speed Twin, when worked hard, overheated,
00:32:39and had poor exhaust valve durability and might detonate, even on the very low compression ratios of that time, which were six to one, six and a half to one.
00:32:53The fuel wasn't all that great either because England during the war, people could see the gasoline, but they weren't allowed to buy it.
00:33:03It came in these great white tank trucks with red lettering that said, what did it say?
00:33:12Pool, meaning this is the gasoline that the refineries have pooled together to make some nasty stuff that the post office and the military can use to drive around the public roads.
00:33:27Pool petrol, 72 octane.
00:33:30Oh, you can hear it knocking in the can, as I like to say.
00:33:37So Hopwood was determined to overcome the shortcomings of the Speed Twin.
00:33:44The first thing that he saw was that the Triumph had two rocker boxes transverse across the head, the exhaust rocker box in the front.
00:33:58There was a camshaft directly under it, the intake rocker box behind the cylinder.
00:34:03And they were like fences, preventing cooling air from what you might call systematic circulation through the cooling fins that were located directly over the combustion chambers between these rocker boxes.
00:34:19So you can imagine building duct work.
00:34:22If this were an aircraft engine, there would be duct work that would feed it down into one side of those fins, would cross the head and then come up the other side.
00:34:32And there would be a pressure difference across the ducting to ensure that the cooling air moved swiftly on its way.
00:34:39Oh, yeah, big deal, all that stuff.
00:34:41The big radials.
00:34:42Yes.
00:34:42The path.
00:34:43So much sheet metal on those engines.
00:34:46And even just the simple stuff, the flat fours and the flat sixes on your, you know, Grumman Tigers, your 0300s and all that.
00:34:52Yep.
00:34:53Yeah, it goes in the front, behind the prop.
00:34:55And then there's all this hard ducting with silicone, usually now silicone flaps sealing against everything to force it all straight down the bottom.
00:35:06Through the fin space.
00:35:08Through the fin space.
00:35:09It doesn't just blow on the engine like it was a warm fence post.
00:35:13Yeah.
00:35:14So he's going to get rid of that.
00:35:18How's he going to do it?
00:35:20Well, in the old days, the first days of overhead valve, the rocker shafts were mounted on standoffs on top of the head.
00:35:31And they're up there in the air, chittering back and forth.
00:35:35And the cooling air was free to pass through the four and a half fins on the head.
00:35:41Wonderful cooling.
00:35:42But people didn't like ruining their pants and shirts with the oil thrown off by unenclosed valve gear.
00:35:54So enclosed valve gear became a very important feature to have.
00:36:00So that meant that you weren't going to build an enclosed rocker box mounted on standoffs and then connect pressure oil to it with an external line and a drain back.
00:36:14All those parts, more parts, more cost.
00:36:19So they cast the rocker boxes as part of the cylinder head.
00:36:23Good solution on one basis.
00:36:26Not so good on another basis.
00:36:28So here's what Hopwood did.
00:36:31If you look down on the triumph cylinder head, you will see the two pairs of valve stems, intake and exhaust for each cylinder.
00:36:41You look down on it and there, four and aft, the plane down through the valve stems is parallel to the central plane of the motorcycle.
00:36:50He rotated those planes apart a considerable amount, like 25 degrees per side, and broke the front rocker box into two separate exhaust rocker boxes.
00:37:08In the space, thus created air was able to flow directly into the fins, which went from that opening in the front between the rocker box, intake and exhaust rocker boxes on that side of the cylinder head and out, which meant direct path cooling.
00:37:31As long as the motorcycle was moving, as long as the motorcycle was moving or there was wind, air would be moving through those fins.
00:37:39The next thing that he did was, he had obviously sat and looked at the triumph cylinder head.
00:37:49It had a 90 degree angle between its valves because it had a deep hemispherical combustion chamber.
00:37:56Well, he'd had a geometry class and he knew that a hemisphere has double the surface area of a disk having the same diameter.
00:38:14So that, what this did was, it provided large amounts of surface area in the combustion chamber through which heat could leave the combustion, hot combustion gas and cause the cylinder head to heat up.
00:38:36And the engine would make less power because the heat, you want the heat to stay in the chamber, not to go running out elsewhere.
00:38:42Where it's not doing the work that you want it to do.
00:38:46It's just turning into melting your stuff.
00:38:49I just want to pause for a second and say, the combustion chambers we have now, the valve stems are typically parallel, vertical, practically vertical in the cylinder, maybe a little bit of kick.
00:39:03And then the combustion chamber, the piston is almost as flat as it can be.
00:39:08It will have a band around the outside for squish.
00:39:10You know, a modern piston is going to look like this, this one here, quite flat, some cutouts for the valves.
00:39:18No dome.
00:39:19No dome.
00:39:20And the chamber is going to be like right on top of it.
00:39:23Yep.
00:39:23Whereas here, this is typical British hemispherical combustion chamber.
00:39:30And then this is from a Jaguar, which is like 35 and 40 degrees.
00:39:35So the valves are set and they open this way into the cylinder to trying to get a bigger area.
00:39:42Yep.
00:39:43And then having that great big dome.
00:39:44And boy, if you want an engine that knocks, it's a 3.8 liter Jaguar at 1800 RPM.
00:39:50Like 100 octane?
00:39:52No, it won't.
00:39:53But 93, it might.
00:39:54Yeah.
00:39:55It's really challenging.
00:39:57Anyway, carry on.
00:39:58Yep.
00:39:59So why was this wide valve angle adopted in the first place?
00:40:08I think what happened was around 19, in the early 20s, a design team at Fiat was developing a Formula One engine.
00:40:18And I think they did some flow testing because somehow they discovered that the flow coefficient, that is the specific flow, cubic feet per minute per square inch of valve head area.
00:40:36And this allows you to compare engines with different size valves in terms of specific flow.
00:40:44So they found that the flow through a single intake valve into a combustion chamber that was a hemisphere or curved like a hemisphere was better than the flow from two intake valves in a four valve head located on the flat surfaces of the pent roof combustion chamber.
00:41:08So they said, well, let's, let's, let's, let's give that a whirl.
00:41:15Well, we can't fit valves big enough in there.
00:41:18Well, if you, if you, if you, the stems are like this and you have a small bore engine, the valves are going to be small as well.
00:41:25So let's tip the valves apart so that they form a sort of tent-like affair over the piston.
00:41:36And there's more room in that diagonal than there is straight across the piston.
00:41:42So tipping the stems widely apart allowed the valves in a two valve engine to be larger.
00:41:50Well, when Hopwood reduced valve size, didn't he choke his engine off?
00:42:01No, because in the, in the late twenties, airflow studies had shown that you didn't need valves that big.
00:42:09And as the design of valves and ports improved steadily, the size required for an engine, um, didn't, uh, grow rapidly.
00:42:26So Hopwood said, look at those Guzis.
00:42:31They've got a 58 degree valve included angle.
00:42:35Works for them.
00:42:37So he adopted that.
00:42:39This made the hemi chamber.
00:42:44Shallower.
00:42:45And of less of reduced surface area.
00:42:49So that it.
00:42:52Did not pick up as much heat from the hot combustion gas.
00:42:57And with the shallower chamber.
00:43:00As compression ratios were beginning to rise as pool petrol was.
00:43:05Replaced by something better.
00:43:07I think 80 octane was the first step.
00:43:12The piston crown could be flat.
00:43:15No big dome to increase the heat flow into the piston.
00:43:21Pistons are hard to cool.
00:43:23So a flat top piston was a blessing.
00:43:29And, uh, the last thing that he did was he did not follow in the train of smaller strokes and larger boars.
00:43:42Because he knew that heat loss from combustion gas was proportional to combustion chamber surface area.
00:43:51A small bore and a long stroke.
00:43:54Good.
00:43:56Low heat loss.
00:43:57Faster combustion because the flame doesn't have to go as far.
00:44:00They made some experiments at American Honda with three different strokes on one of their superbike engines.
00:44:10And as they reduced the bore size, the ignition timing required for best torque became smaller and smaller.
00:44:21The next thing that Hopwood did was he offset the intake ports as they had been offset on successful British racing engines such as the Norton Manx.
00:44:35By offsetting the port, you cause the flow to circulate in the cylinder.
00:44:45That does.
00:44:46You play with the hose in a bucket.
00:44:48Yes.
00:44:48That's my favorite.
00:44:49Because if you aim the hose at the side, it goes, whew, and it just has all kinds of velocity and turbulence.
00:44:54And you're standing there waiting for this bucket to fill, which is not the most satisfying activity.
00:45:01So you play a little.
00:45:04This is called learning.
00:45:06Nobody teaches you this.
00:45:08You see it.
00:45:11So combustion chamber, you're talking about lighting, you know, making the bore really big.
00:45:15So if we have 115 millimeter, 116 millimeter bore, the fire, even if a perfectly flat chamber, the distance it has to go, if you light it over here, or even if you light it in the middle, it's got a long way to go.
00:45:29If you have a Hemi, not only is there more surface area, but if you light it over here, it has to, the flame has to travel over the mountain and get to the other side.
00:45:37It's a longer distance.
00:45:38It's like twice as far.
00:45:40Yep.
00:45:40And that's why, you know, that's why in a lot of these Hemi's, like a second, a second spark plug, they'll take a tiny, they'll take one of these, one of these Ducati, tiny Ducati spark plugs and stick it on the other side of the chamber.
00:45:54Ducati, big bore, super bike stuff, two plugs, Harley Davidson.
00:45:58We don't talk about how big the bore is in a Harley Davidson, but those 131s, man, that's a four inch bore.
00:46:04Yeah.
00:46:04Put two plugs in each one of those things because you can light the fire in two places.
00:46:08And the overall distance that the flame has to travel is shorter, meaning your timing can be shorter, or you shrink the bore, as you were talking about with Honda.
00:46:17Now.
00:46:17Getting, and just.
00:46:21One fellow said, an engineer once said to me, I don't see that it makes much difference if my engine needs, makes best torque at 40 BTDC.
00:46:3040 degrees of ignition, you should be ashamed of yourself, because for 40 degrees before and roughly 40 degrees after, the molecules are beating hard against the piston crown and the inside of the combustion chamber.
00:46:47And they are transferring that energy to those molecules.
00:46:53This is called heat flow.
00:46:56These molecules come up, pow!
00:46:59They set that molecule vibrating.
00:47:02It's bonded to all the atoms around it.
00:47:06That motion is transmitted to them through the bonds.
00:47:09This vibration is temperature.
00:47:12That's what temperature is, is molecular energy.
00:47:18So, by shortening the combustion time, Hopwood shortened the heat loss time.
00:47:27So, now we've got his other bugaboo, which was, he thought of the Triumph as a rattler.
00:47:37He said, the front and the rear cams, there's two cam drives in there, and they both rattle because they're gears.
00:47:46He drove his cam, which was in front of the cylinder, through a chain.
00:47:50And instead of having separate pushrod tubes that had to be fitted in and make sure that the seals don't pop out of the little recesses at the end, it was cast into the cylinder.
00:48:04You put the cylinder on, and then you put the pushrods down in there and made sure that they were seated in the tappets.
00:48:11And then you could deal with the cylinder head.
00:48:13So, he was able to quiet the engine in that way, just because he wanted to.
00:48:23Norton rewarded him by firing him in about 18 months, because people were claiming that the engines were short-lived, and they didn't do this, and they didn't do that.
00:48:34The engines did an outstanding job for Norton for 30 years.
00:48:38And, although they did increase the displacement, they kept close to the original small-bore long-stroke formula.
00:48:52Now, there is this belief that will not die, so I don't bother trying to inveigh against it too much, that long strokes make torque.
00:49:06It just stands to reason.
00:49:09If you've got a longer lever, you're going to be able to, you know, that's why an extension bar on your wrench, if it doesn't wreck the wrench, increases your leverage in tightening or loosening the fastener.
00:49:26So, what you find if you do the arithmetic is, if we have, say, a 500, and this engine, which was called Dominator or Model 7 to begin with, it was a 500.
00:49:43So, if you're choosing a bore-to-stroke ratio, each time you make the stroke longer, the bore has to get smaller to keep the engine at 500 cc's, and the pressure, the area of action for gas pressure on the piston decreases at exactly the same rate that the stroke increases.
00:50:09So, there is no numerical advantage.
00:50:14The reason why we associate high torque with small-bore long-stroke engines is they have small valves.
00:50:22Valves have a range of velocities in which they do their best cylinder filling.
00:50:30Too fast, and you're tending to have sonic velocity and shock formation and so on, and this is going to reduce the flow.
00:50:42Too low, and the piston coming up as the valve is closing, is going to not only stop the inflow of mixture, but push some back into the intake port.
00:50:54We've discussed this before.
00:50:55So, there is no mathematical reason that a long-stroke engine should do better than one, should produce more torque than one with a shorter stroke, but the same displacement.
00:51:12The reason that the long-stroke engines seem to have good torque is that they have smaller valves.
00:51:18And their torque, their peak delivery occurs down at lower revs.
00:51:26And this has been the reason why, from start to finish, those Norton twins have been noted for strong mid-range.
00:51:36They have located the RPM of best cylinder filling in the range that people actually use when they're riding.
00:51:45I'll tell you what, a Norton 850 Commando, 77 by 89 millimeters, or 828 cc's, third gear, about 3,000 RPM, is a thing of beauty.
00:51:57You roll into that, you appreciate a 28-degree maximum ignition timing, all in, as we would say.
00:52:05All in, yes.
00:52:07It is a happy engine.
00:52:08I mean, it's vibrating its guts out, thank goodness for Isolasix, because every time they kick that displacement up, it just started shaking the stuff more.
00:52:17But I think what you're talking about on the intake air velocity is so interesting.
00:52:22For me, what's engaging about the notion is that air has mass.
00:52:27And that velocity, when you make the port smaller, because that's all that fits in that smaller bore, longer stroke engine,
00:52:36the mass of the air coming in at high velocity fills, and you can have cam timing that won't be able to counteract that and push it back out, as you said.
00:52:50And as, you know, I like my analogy for flow and diameter is take a straw and blow in the straw as hard as you can, and how much air comes out.
00:53:01And then take your garden hose or get your shop vac tube and blow as hard as you can.
00:53:05You barely feel it on the other end of that four-inch hose.
00:53:09And that is one of the differences, is there's an optimal airflow.
00:53:13Because of this, the air has inertia, so when the piston starts to move down on the intake stroke, the air in the intake pipe is sort of...
00:53:26Do you feel the pressure somewhere?
00:53:29Oh, yeah, people are heading for the exit.
00:53:32It takes time for that mass of air to accelerate.
00:53:36So the piston has gone some distance before the air motions begins to catch up.
00:53:41So most of the cylinder filling occurs toward the end of the valve period.
00:53:48And if you have late closing, not an awful lot, so that you've got to build a peaky monster,
00:53:54but enough to take advantage of all that air velocity around bottom center,
00:54:01that relatively high velocity through smallish valves will continue to crowd its way into the cylinder,
00:54:10even as the valve is closing.
00:54:13So that's a wonderful thing.
00:54:17Now, Mark mentioned 28 degrees.
00:54:21The first, the very first, the 500 Norton Twin, as Hopwood first conceived it,
00:54:28its timing for best torque was somewhere between 28 and 31.
00:54:32So it was there from the beginning.
00:54:35It was there at the end, and people enjoyed it throughout those 30 years.
00:54:41And now as their collector's items.
00:54:44Brother, you know, the team's getting thirsty here, but I'm going to bring up Velocet,
00:54:48because that was a square borne stroke, the 586 by 86.
00:54:53And it's a hemispherical chamber.
00:54:55I don't know what the valve angle is between the stems, but it's quite wide.
00:55:01And, you know, when you're setting that up, if you read the books, they want 38.
00:55:05That's 10 more degrees of lead.
00:55:07So you're lighting it so early, because it takes that long to build the peak pressure
00:55:12for after top dead center when the piston's in the ideal position, which is what, 17 degrees or something?
00:55:17No, 11, something like that.
00:55:19It's when it really starts to move, rather than just, here I am on the hilltop.
00:55:25It's a nice broad.
00:55:26Well, think about the dead stop at the top.
00:55:29You know, the piston comes up, and the rod is swinging.
00:55:31And then in that last bit of area, the piston is at top dead center.
00:55:35It's barely moving.
00:55:37The rod is straight up, yeah.
00:55:38Yeah, and then the rod goes straight, and it comes to a complete stop.
00:55:42And then it starts to go, okay, we're going, going.
00:55:44And by the time you're out here, the lever is working, and the piston is accelerating.
00:55:49And this is the area where you want to go peak pressure.
00:55:52So if you have a great chamber, you can light it 28 degrees before that.
00:55:56That's before top dead center, so it would be 38 degrees before you wanted the peak pressure.
00:56:01But it would be 48 degrees on the VeloCette, which I struggle with knock.
00:56:06And then I only time it, say, for modern gas.
00:56:09I time it for 35.
00:56:11Yeah.
00:56:11Because that's all I can get away with, with what we have at the pump here, 91 at the pump.
00:56:16You know, if you put race gas in it, or cheater gas, as my friends on the VeloCette rally would call it,
00:56:22you can rev with impunity.
00:56:25You can set the timing with impunity and just get whatever maximum torque you want out of it.
00:56:30But, you know, I have to say, from the entire time I owned that Norton Commando
00:56:34using both a mechanical ignition advance, you know, weights before they wore out,
00:56:40and then using an electronic ignition called a TriSpark.
00:56:44I don't think I ever had detonation in my Norton Commando.
00:56:52Yeah.
00:56:52And what a freeing thing that is to not have to hassle with it or figure out what to do with the ignition timing,
00:56:58because it's just good.
00:57:01Yeah.
00:57:02Imagine.
00:57:03They told people who were operating the Norton factory racers that no operation below 3,500,
00:57:13because for a racing engine, you set the compression ratio so that you are on a detonation stormat.
00:57:27So, you're very close, because otherwise you're leaving some pressure on the table.
00:57:35Remember, peak pressure is something like 100 times the compression ratio.
00:57:41So, this is a lovely story, because I was this morning looking at a cross-section of one of the Norton Twin heads.
00:57:53It has 15 degrees of intake downdraft.
00:57:58Now, that was something that Norton crept up on in the development of their racer.
00:58:05Originally, there was no downdraft at all, and then they had a little, then they had 12, then they had 15.
00:58:13They ended up with 24, because they found that the steeper the downdraft angle, the less charge was lost during overlap,
00:58:26the time when both valves are open, briefly, a small amount, lost out the exhaust.
00:58:35Because the exhaust, there's that low-pressure wave that is trying to aspirate exhaust residuals out of the combustion chamber.
00:58:43The intake valve is slightly open, and you don't want to aim the intake flow at the exhaust port.
00:58:54So, that's why downdraft became an important thing.
00:58:59And the port that's pictured in that cross-section is unremarkable.
00:59:04It's smooth.
00:59:06The curves, the short side of the port is smoothly curved.
00:59:11The downdraft angle is not extreme.
00:59:15In the early 90s, Kawasaki was using 45 degrees of downdraft.
00:59:22I believe the Cosworth people played around 30 to 35.
00:59:27It's, it's, there's a lot of stuff that was pioneered in those original Norton racing engines,
00:59:37and there was a lot of careful thought by Hopwood on how to avoid the problems of overheating with an air-cooled engine.
00:59:47The problem, basic problem of an air-cooled engine is going to run hot on a hot day, and colder on a cold day.
00:59:55If it's cold enough, it won't vaporize all of its fuel, and it'll be lean.
01:00:01So, air-cooleds have some special problems, and I think Bert Hopwood applied himself in an effective way to solve many of them,
01:00:11or at least to keep them at bay.
01:00:17By the way, contemporary engines, British twins, were needing 36, 38 degrees.
01:00:28In the 1930s, some of those overhead valve engines were requiring 42 degrees.
01:00:39So, to fire at 28 degrees is a wonderful accomplishment.
01:00:46It's very close to the number that Dick O'Brien had achieved with their Battle of the Twins bike, which was 27.
01:01:07Dick O'Brien is a long-time racing manager, director guy at Harley-Davidson.
01:01:11Harley-Davidson.
01:01:12Legendary.
01:01:13Yeah, legendary.
01:01:1457 to 84.
01:01:17Yeah.
01:01:18And a man of salty speech.
01:01:20Very salty speech.
01:01:21And in his retirement, I interviewed him.
01:01:25Well, his air-quote retirement, I interviewed him when he was in Florida.
01:01:29And that was my contact with him, a phone interview.
01:01:32I called him, and I got all the punctuation that he used.
01:01:37Yes.
01:01:38F-bombs and S-bombs and all of that.
01:01:39And they were just, everybody was still, he said, I'm trying to fucking retire and this and that.
01:01:47I mean, fucking, send me the damn, man, goddamn, you know, on and on.
01:01:51And they were sending him cylinder heads.
01:01:53They were sending Dick O'Brien NASCAR cylinder heads and sprint car cylinder heads for him to do boarding and chamber work in his retirement in Florida.
01:02:04They were mailing him stuff, and he was getting it done.
01:02:06So-called retirement.
01:02:07It was wonderful to talk to him.
01:02:08Very special.
01:02:10I went, I visited him before he went south, and he described how he spent the war, World War II.
01:02:20He was with a unit whose job was to restore to flight status, captured enemy aircraft, usually shot down, or ran out of fuel and landed in the field.
01:02:32Have I ever heard a vocation?
01:02:34I want to do more.
01:02:38Dang it.
01:02:39I missed my calling.
01:02:40So what they were doing there was, as quickly as possible, restoring these aircraft to flight status so that test pilots could ascertain their strong and weak points so that allied pilots could understand what they were up against before they were up against it.
01:03:00And he said, and he said, and he said, and he said, nobody wore a shirt if it was hot, nobody buttoned a button.
01:03:08He said, nobody polished anything.
01:03:10He said, then the war ended, and we got a new CO, and he said, we were unsold, surely.
01:03:20Well, there were a lot of guys at Pratt & Whitney who tried to enlist, but they weren't allowed to because material command said, these are essential people in essential occupations.
01:03:33If you're developing superior versions of the R-2800 radial, you're doing better than if you're stopping bullets out in a muddy field.
01:03:46And so it was with these men readying captured enemy aircraft for flight test.
01:03:53And so he said, all the best guys left, and the ones who didn't want anything but a paycheck stayed where they were.
01:04:03But he said, it was fun while it lasted.
01:04:09He described one engine that was remarkably free of valve flow.
01:04:21And he said, we looked at that thing all different ways.
01:04:26And he said, finally, we crack tested the rocker arms, and one of them had a little crack coming.
01:04:36And he said, I'm thinking the extra flexibility of that just happened to fit with something that was going on in the valve train,
01:04:47because he said it was very different, that one.
01:04:51It's interesting the way that, you know, vibrations and all the hertz can stack for or against you.
01:05:02Yeah.
01:05:03Crank vibrations, having crank tampers, or changing an aircraft from a wood prop.
01:05:09To a metal.
01:05:10To a metal one.
01:05:11Yeah.
01:05:11You know, the Stinson uses a 165 horsepower engine, six cylinder, and on a wood prop, you can kind of fly it however you want.
01:05:22But with a metal prop, there's a band of RPM, like 2,800 to 3.
01:05:26I don't know what the specifics are, but it says, don't run here.
01:05:29No fly zone.
01:05:31Don't run here.
01:05:32Yeah.
01:05:32You can pass through it to go up to peak power, and you can run below it, but don't run at there.
01:05:38What?
01:05:38I rode several test bikes home, and there was a section of road that was under construction.
01:05:49The road wasn't under construction.
01:05:50There were houses under construction, and they had cut trenches, and they cut these trenches at a gap, right?
01:05:56There's a series of these trenches, and every motorcycle I rode over those bumps lost it.
01:06:07Not one could cope, because there was something about the cycle of those impressions on the suspension.
01:06:14The frequency of the suspension, yeah.
01:06:17Yeah.
01:06:17It made everything horrible for that brief moment.
01:06:21For the two and a half seconds, I was going grrr.
01:06:24The bike just, it was gone.
01:06:26The suspension was like, ah, I don't know what to do.
01:06:29And the bike would go, grrr, and then it was back.
01:06:32It was fascinating.
01:06:34I should have measured that, and then calculated my speed, and made that part of it.
01:06:39You spoke of vibration in regard to Commando and 850.
01:06:46Doug Heal took over from Joe Craig, development of the Manx.
01:06:52And they continued toward shorter strokes, and I think he got as far as 93 by 70 something.
01:07:03And he said, comparatively, it was a very smooth engine.
01:07:08Because, of course, as you shorten the stroke, you are reducing piston velocity and primary shaking force.
01:07:24Yeah, the very late Manxes were the so-called short stroke ones.
01:07:28They had to depart from the five-piece crankshaft because they found that they couldn't, the crank pin would intrude on the main shaft.
01:07:41So, on one side, the crank pin was made integral with the flywheel, and so they only had the one press fit.
01:07:52But in 1961, when Mike Hale would won the last TT to be won by a Manx Norton-powered bike, his bike had a one-piece crankshaft, machined from solid.
01:08:08And it had a Jaguar plane bearing connecting rod, the reason being that starting in the late 50s sometime, crank pins would just break.
01:08:21And you couldn't say, oh, well, the crank pin's good for 15 hours.
01:08:27It would happen at random.
01:08:31So, they decided, let's just forget this rolling element bearing business and modernize.
01:08:40So, they made the one-piece crank with a hefty crank pin with nice, smooth fillets where it joined the cheeks.
01:08:50And those were reliable at higher revolutions.
01:08:54In 1961, that was the last time a Manx won the Isle of Man.
01:09:00And it happened because the throttle sticking on the MV, which had led.
01:09:07Well, we'll take it, right?
01:09:09Win and win.
01:09:10Yep, for sure.
01:09:10Got to get there.
01:09:11100% doesn't make the grid, and then how do you get to the finish line?
01:09:16Yep.
01:09:17I think the pressed-together crank is just a funny piece of history because RD350, XS650, roller bearings, GS, Suzuki GS1000s, roller bearings and stuff.
01:09:33It's just crazy that it went on that long.
01:09:35But it was, you know, it was working fine.
01:09:37I mean, I think for me, the hilarity for the 350, the RD350 was when we did my RD350 engine in your shop.
01:09:46And we had kind of a miscommunication about, well, we were thinking of the same thing, except the picture of what we were thinking was completely different.
01:09:57And I said, oh, mid-range motor.
01:09:59And you said, oh, yeah, mid-range motor.
01:10:01And your idea of mid-range as a race tuner on a 350 two-stroke twin was different than mine as a street guy who had ridden this bike for many thousands of miles on the street.
01:10:12And so you went over into the corner, and you were all porting away, doing your thing.
01:10:16And I was over cleaning the case halves and wiping off old three-bond, which you, thank God you told me it would wipe off with lacquer thinner.
01:10:26Yep.
01:10:26Because I was over there trying to scrape it.
01:10:27And you're like, you know, anyway, I'm doing all of that, and you're grinding away.
01:10:32And I said, yeah, so torque.
01:10:33And you're like, yeah, torque.
01:10:35And then I say, so, like, what are we looking at?
01:10:37You know, like three to seven, three to six, because the red line, I think, is nine on those factory, factory red line on the RD350 is 9,000.
01:10:45And I said, ah, three to seven.
01:10:47And you looked at me and said, three?
01:10:49Yeah.
01:10:52And you're like, no, it's going to make torque from, I think you said seven to 11.
01:10:56Seven to something, yeah.
01:10:59Yeah.
01:10:59Or seven, whatever you said.
01:11:01But it was over the factory red line.
01:11:03And just casually, you say, yeah, you're going to have to do something about the, you know, the charging ignition and all that.
01:11:09Because it walks off the crank at higher RPM.
01:11:14Yeah.
01:11:14That's a press together.
01:11:15The ignition side flywheel walks off the crank pin, yeah.
01:11:18Yeah.
01:11:19And that's pressed together.
01:11:20Like, it can work really fine up to a point until it doesn't.
01:11:23And either the pin, you know, the pin's under a tremendous amount of stress.
01:11:27The flywheel's under the press.
01:11:28And the flywheel, the crank pin, this will be the crank pin joining the two flywheels.
01:11:33And the flywheels are doing this.
01:11:36Yeah.
01:11:37And that means that there's continuous slight motion in the press fit.
01:11:44That's why when you press it apart, the parts have a reddish color.
01:11:48Yeah, red fretting.
01:11:49Yeah.
01:11:50That's iron oxide, a.k.a. rust.
01:11:54If you go up to some of the vintage aircraft that I hang around with, the props are held on with a spline, a very large spline, square edge spline.
01:12:06And you can see red fretting.
01:12:10And what's interesting about that is if you look at, you know, one of these big splines, there'll be red fretting in an area over here, but not over here.
01:12:19And I'm thinking, like, well, this is the engine having a vibration that causes something that seems to be located in that area, but not somewhere else.
01:12:28Propeller's doing something.
01:12:30Yeah.
01:12:30Or they, you know, they didn't, I don't know, lubricate it.
01:12:33Up here at the local FBO, there was a little motor glider outfit that was just about to try to launch their stock on the stock exchange.
01:12:46And they had this weird vibration.
01:12:51They're using plastic propellers.
01:12:55And they weren't getting anywhere.
01:12:57And they brought in a French guy who was a vibration specialist.
01:13:02And he said, put a three blade on it and you'll be fine.
01:13:07And they did.
01:13:08And it just settled right down.
01:13:09So, when the, when the R2600 was put into, entered the war, it was, of course, always with metal propellers.
01:13:21And the prop mounts on mounting cones and is driven by the spline.
01:13:30And so, when they would take the prop off for service, they would look at these mounting cones and they're covered with threading or welding and seizing.
01:13:43Because the crankshaft is not rotating smoothly.
01:13:47It's kind of going da-da, da-da, da-da, da-da, da-da.
01:13:49And the prop blades are, are waving around out there.
01:13:55And chunks of prop blade could develop a crack somewhere where the bending moment was considerable.
01:14:05And a piece would ultimately fly off.
01:14:08There was a, that case of a constellation in 1948 on a flight to Miami.
01:14:13A piece of prop came through the fuselage and killed somebody.
01:14:17Um, that's another case of the, of the no-fly zone.
01:14:23There were certain RPM, engine RPM, that were not to be used.
01:14:28You can pass through it, but do it quickly.
01:14:31And in pre-war submarines, before they decided to solve the problem with diesel electric drive,
01:14:39they had, they broke a lot of crankshafts.
01:14:42The crankshafts, of course, were a mile long.
01:14:44And, uh, they could put, uh, the MIT tarsiometer on there and measure, um,
01:14:55it would draw out all the, all the peaks and valleys.
01:14:58And they would say, okay, this is a forbidden zone and this and this.
01:15:02And it was driving, uh, engineers, uh, crazy.
01:15:08So they decided, we'll run the engine at constant speed, the safest possible zone where the crankshaft is just lying there rotating.
01:15:19And we'll, uh, vary the propeller speed by driving it through electric motor.
01:15:26And that worked very well, diesel, electric.
01:15:31Same thing with locomotives.
01:15:34Locomotive engine, um, and a submarine engine were very close for a long time in, in their design.
01:15:42Somebody out there is doing a pickup truck.
01:15:44I think they've got a prototype for basically a diesel electric so that you can have a very efficient, uh, generation of power.
01:15:50And then the power, uh, comes out through electric motors.
01:15:53Yeah.
01:15:55Well, electric motor has a torque characteristic that all of our, uh, cleverest engineers have devoted themselves to making IC engines act like an electric motor.
01:16:07And, um, I'm not, I'm not pushing for electric motors.
01:16:12I'm just pointing out that they have an excellent torque characteristic, provided that you have a convenient source of electric power to run them.
01:16:23Yeah.
01:16:25So looking for the most convenient source for that.
01:16:29Well, that's Norton Commando, folks.
01:16:34Anyway, we are not Norton Commando.
01:16:35That's Norton.
01:16:36And, uh, we'll, uh, we'll wrap it up here, but, uh, hope you enjoyed the tour.
01:16:42We've got a lot of topics into the broad, you know, Norton, uh, topic, a lot of combustion chamber and bow angles, all the stuff that matters.
01:16:52It's all we've ever been trying to do is broaden the torque curve, make the running as near perfect as it possibly can be.
01:17:00Such satisfaction where the cycle to cycle variation is nil or close to it.
01:17:06That means smoothness.
01:17:07It just means every combustion event is the same, which is sort of something we've always been striving for.
01:17:13And to some degree we've achieved.
01:17:15It's what I try to do with all my old junk.
01:17:17You know, how do we, how do we walk out to our 1972 Yamaha XS 650?
01:17:23Turn on the fuel taps, hit the choke, and kick it one time to start.
01:17:29Dumb, dumb, dumb, dumb.
01:17:30Yes.
01:17:31Yeah.
01:17:31You know, you try to achieve all that.
01:17:33It's, uh, good times.
01:17:35Thank you for listening.
01:17:36We will catch you on the next one.
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