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Theory of 4 valve poly quad cylinder heads.

General engine tech -- Drag Racing to Circle Track

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Truckedup
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Re: Theory of 4 valve poly quad cylinder heads.

Post by Truckedup »

hoffman900 wrote: Tue Sep 17, 2019 12:48 pm
Not sure where that is measured at though. You could always email Kevin Cameron. Yoshimura, Dan Crower, Honda, YEC (Yamaha), all advertise some racing camshaft numbers if that will help.
[/quote]

On two valve Ducati's ,cam timing is checked at one millimeter, .040..I suspect the new engines are the same ? Not enough biker's pay attention to Kevin Cameron,and very few car guys know who he is...

Kevin Cameron,he can be more complex than this example but he does have a way of making stuff understandable...

https://www.youtube.com/watch?v=opXmdzLIM4o
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Re: Theory of 4 valve poly quad cylinder heads.

Post by 4vpc »

Truckedup wrote: Fri Sep 20, 2019 6:52 am
hoffman900 wrote: Tue Sep 17, 2019 12:48 pm
Not sure where that is measured at though. You could always email Kevin Cameron. Yoshimura, Dan Crower, Honda, YEC (Yamaha), all advertise some racing camshaft numbers if that will help.
On two valve Ducati's ,cam timing is checked at one millimeter, .040..I suspect the new engines are the same ? Not enough biker's pay attention to Kevin Cameron,and very few car guys know who he is...

Kevin Cameron,he can be more complex than this example but he does have a way of making stuff understandable...

https://www.youtube.com/watch?v=opXmdzLIM4o
[/quote]

With respect he just comes across as another guy with an opinion in that video.
There is no S on the end of RPM.
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Re: Theory of 4 valve poly quad cylinder heads.

Post by Truckedup »

4vpc wrote: Sat Sep 21, 2019 5:02 am

With respect he just comes across as another guy with an opinion in that video.
Because it's somewhat relavent, I would be interested in your opinion on the topic ...
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4vpc
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Re: Theory of 4 valve poly quad cylinder heads.

Post by 4vpc »

Truckedup wrote: Sat Sep 21, 2019 7:52 am
4vpc wrote: Sat Sep 21, 2019 5:02 am

With respect he just comes across as another guy with an opinion in that video.
Because it's somewhat relevant, I would be interested in your opinion on the topic ...
We don't need another opinion, we need some facts :D He doesn't mention any testing he's done on the subject.
In his vid he claims that tight squish isn't used on production engines because they aren't accurate enough, that's not true at all, we're not in the 1940s any more.
DV says it's because emissions go up when squish is tight, A. Graham Bell on the other hand says that the mixture can actually get trapped between two parallel surfaces, that he's removed squish pads and seen a power increase on some engines, many turbo guys are making more power (because of lesser det' limits) by also removing squish pads.
Me? I sit on the fence observing because I don't have the funds to test. I sometimes think that if I won that big cash prize i'd buy some time, some equipment and do some testing of my own, but that's just a dream.
There is no S on the end of RPM.
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Re: Theory of 4 valve poly quad cylinder heads.

Post by Truckedup »

4vpc wrote: Sun Sep 22, 2019 6:28 pm
Truckedup wrote: Sat Sep 21, 2019 7:52 am
4vpc wrote: Sat Sep 21, 2019 5:02 am

With respect he just comes across as another guy with an opinion in that video.
Because it's somewhat relevant, I would be interested in your opinion on the topic ...
We don't need another opinion, we need some facts :D He doesn't mention any testing he's done on the subject.
In his vid he claims that tight squish isn't used on production engines because they aren't accurate enough, that's not true at all, we're not in the 1940s any more.
DV says it's because emissions go up when squish is tight, A. Graham Bell on the other hand says that the mixture can actually get trapped between two parallel surfaces, that he's removed squish pads and seen a power increase on some engines, many turbo guys are making more power (because of lesser det' limits) by also removing squish pads.
Me? I sit on the fence observing because I don't have the funds to test. I sometimes think that if I won that big cash prize i'd buy some time, some equipment and do some testing of my own, but that's just a dream.
That's stuff Cameron does on videos isfor the general motorcycle riders, not hard core tuners. He can be hard core, do some research on him..And yes, production bikes especially in the recent past do avoid tight squish even when it's not emissions related to avoid contact damage ...He did say that in the video...
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Re: Theory of 4 valve poly quad cylinder heads.

Post by 4vpc »

Truckedup wrote: Mon Sep 23, 2019 6:24 am
4vpc wrote: Sun Sep 22, 2019 6:28 pm
Truckedup wrote: Sat Sep 21, 2019 7:52 am

Because it's somewhat relevant, I would be interested in your opinion on the topic ...
We don't need another opinion, we need some facts :D He doesn't mention any testing he's done on the subject.
In his vid he claims that tight squish isn't used on production engines because they aren't accurate enough, that's not true at all, we're not in the 1940s any more.
DV says it's because emissions go up when squish is tight, A. Graham Bell on the other hand says that the mixture can actually get trapped between two parallel surfaces, that he's removed squish pads and seen a power increase on some engines, many turbo guys are making more power (because of lesser det' limits) by also removing squish pads.
Me? I sit on the fence observing because I don't have the funds to test. I sometimes think that if I won that big cash prize i'd buy some time, some equipment and do some testing of my own, but that's just a dream.
That's stuff Cameron does on videos isfor the general motorcycle riders, not hard core tuners. He can be hard core, do some research on him..And yes, production bikes especially in the recent past do avoid tight squish even when it's not emissions related to avoid contact damage ...He did say that in the video...
Sorry, but both you and he are wrong if you think that excessive squish clearances are down to sloppy machining, not in this day and age.
There is no S on the end of RPM.
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Re: Theory of 4 valve poly quad cylinder heads.

Post by williamsmotowerx »

Production GSXR Suzuki's had a service bulletin and special tool to check squish in early 90's.

If it was .028" you were good. If it was .026" you had to put a new head gasket on.

So yes, there was some tight squish stock
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Re: Theory of 4 valve poly quad cylinder heads.

Post by ozyfordman »

A bit off the original topic but the subject of tapered quench pads would apply to PQ and normal valve layouts. Any rules of thumb for this or is it always on a case by case basis. Those of us who don’t have the resources to test are asking for the goodwill of those that have. That’s why I love this forum. Was hoping DV would comment but understand he has had his hands full with REC.
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Re: Theory of 4 valve poly quad cylinder heads.

Post by hoffman900 »

Here is one of the fastest privateer Yamaha R1 Superbike teams engines for sale. The Yamaha is down a little compared to the Suzuki, BMW, Kawasaki, and Ducati in straight line scoot, but they have killer chassis on them. This engine is down a few mph on the factory Yamahas. Check out that torque curve!
2F1CA7DA-D1E1-443B-BC78-5767EBBD1A99.jpeg
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-Bob
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Re: Theory of 4 valve poly quad cylinder heads.

Post by Yoshiboldor »

ozyfordman wrote: Mon Sep 09, 2019 7:56 am I have been asked to develop a race cylinder head for a 450 cc Yamaha single motocross bike. The bike will be used for beach racing over a 500 and 750 metre course over 4 laps around barrels st either end of the beach. The rider is competitive in motocross and enduros.The class is very competitive with a good deal of rule interpretation and very little scrutineering. I would like to explore the poly quad concept and better understand the benefits of this valve layout. A quick search here was unsuccessful. Not asking for a handout but would like to hear the benefits and the theories on how the benefits are achieved. I believe DV has been instrumental in the development of this technology and it is mentioned in one of his books.Is this technology making it into mainstream 4 valve performance mods, or is it still in the top secret department. Any feedback would be appreciated on this topic. I have access to an S&G machine and a flow bench. I have to admit to only working on 2 valve stuff to this point but have an experienced mentor on 4 valve motor cycle race engines. Any thoughts that you care to share will help as I am not clear on the theory.
Did you every polyquad this engine and if so what were the results??
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Re: Theory of 4 valve poly quad cylinder heads.

Post by ozyfordman »

No, went the conventional route. It ran well but didn’t win it’s class.
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