If you could do anything to a cyl head?

[ccb]

I have a ? If you were able to locate the int and ex valve in any location in relationship to the cyl bore where would you put it? Would you rotate the valves 20 degs,or 25 degs,or more? Plus what effect dose this have with power and flow #s. Can the head make more power with less flow? And what are some other things you would do if you could?

I know there are a lot of other factors that make a power difference, but I'm just trying to get some different ideas on this. Their are smart people here I thought this would be good thread.

Pro stock you can do anything you want, so where would you start? The field of work I'm in, you don't get to mess with valve location, it is set by rules by the governing body. I think it's cool as hell that you can do anything that you want to in pro stock, but has to be a can of worms sometimes too. This ? is not just for pro stock but any class of racing that you don't have many rules.

[Unkl Ian]

Since we are talking clean sheet of paper,one thing I want to try
is adding a second spark plug.

[beth]

It would be 4 valve, with about 6 degree valve angle, slight pentroof, small centrally located spark plug. 4 squish areas along with a 360 degree squish band. Intake ports as physically high as valve material and length would allow. 2 intake and 2 exhaust ports per cylinder and about 5 years to perfect it.

[Justin Jones]

It would be 4 valve, with about 6 degree valve angle, slight pentroof, small centrally located spark plug. 4 squish areas along with a 360 degree squish band. Intake ports as physically high as valve material and length would allow. 2 intake and 2 exhaust ports per cylinder and about 5 years to perfect it.

My thoughts exactly.

[#84Dave]

If I personally had right at $337K I didn't know what to do with, I'd build a 5-valve/500"/quad-cam Pro Stock. SAE papers abound that show 3 intakes and 2 exhausts afford the greatest valve area possible inside a pent-roof chamber. With 1.8:1 finger-followers, 105#/120# seat pressures on titanium intake/exhaust valves, the valve train would be 'quiet' until just short of 12,000. Take the 'Stock' out of 'Pro', have fun racing and welcome to the 21st century.

Dave

[Justin Jones]

If I personally had right at $337K I didn't know what to do with, I'd build a 5-valve/500"/quad-cam Pro Stock. SAE papers abound that show 3 intakes and 2 exhausts afford the greatest valve area possible inside a pent-roof chamber. With 1.8:1 finger-followers, 105#/120# seat pressures on titanium intake/exhaust valves, the valve train would be 'quiet' until just short of 12,000. Take the 'Stock' out of 'Pro', have fun racing and welcome to the 21st century.

Dave

5 valve is losing it's popularity, It might flow gobs of air but you can't make a 5 valve chamber burn very good like a 4 valve. VW switched back to 4 valve on their FSI engines and Yamaha is going back to 4 valve with their new bikes like the new R6 I think...

[#84Dave]

Five valves on a 4.6" bore would work very well. With two 10mm plugs next to the outside intakes and exhausts. 40% valve area versus bore area is doable on a large bore with decent spacing between valves for reliability. The age of electronics, FI and turbo's makes 4-valve power just fine on small engines with reduced cost in heads. But normally aspirated and carbs, valve area and rpm is still a wonderful thing.

Dave

[SchmidtMotorWorks]

I have lost track of motorcycle heads, have any of them gone to finger followers?

[SchmidtMotorWorks]

Speaking of followers does anyone have any idea what the performance difference is between a finger follower and a bucket follower on a four valve head?

[SWR]

5 valve is losing it's popularity, It might flow gobs of air but you can't make a 5 valve chamber burn very good like a 4 valve....

Something that engines like the YZF750SP from Yamaha will tell you just from looking at the race spec ignition box' specs... from 7000 rpm on,you're running 50+ degrees of ignition. Still doesn't knock though...

[BCjohnny]

If I could do anything to a head I would make rotary valves (especially the Aspin) at least as reliable as the rest of the engine.

Then we could chuck away all those bl**dy poppet valves..........

John.

[Ape]

I have lost track of motorcycle heads, have any of them gone to finger followers?

Yup all or most of the MOTO Gp bikes do have them in order to run wilder cams without running out of space..
tiny lil levers made out of titanium and coated black, from a well known supplier in the geneve area.

Cheereoh

[SchmidtMotorWorks]

If I could do anything to a head I would make rotary valves

I spent a lot of time looking into rotary valves, problems is none of them seal, and as far as I know they all flow worse than poppet valves when considered over the full duration of the opening.

I made the mistake of posting that I would help someone develop a good rotary valve head in a forum about 7 years ago. I still get replies from people that have rotary valve dreams. Everyone of them has been unsealable, uncoolable, expensive to make, would flow worse than poppets.

[Windsor377]

If I could do anything to a cylinder head?...hmmm...I would throw it away.

My perfect little world will have overcome all the obstacles for a constant speed turbine powered by powered pure hydrogen and oxegen derived from an on board water source, that in turn powers a very light weight electric "generator", that in turns powers an electric motor/brake at each wheel.

Of course, everything is very light weight with very efficient energy transfer rates, tied together by some sort of computerized managment system.

...and, of course the exhaust by products are all rclaimed on board, back into water....

[SchmidtMotorWorks]

powered by pure hydrogen and oxegen derived from an on board water source

Sounds good but what power source will seperate the water in to H and O?

Nuke Power? In that case you could do without the conversion and just steam the water like powerplants do.