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LoopDLoop2

I'm New Here
Well I am getting a little bored again and have thought of building a set of Billet heads for a io360. The heads will use the stock style cylinders and will the stock style valve train. Port locations for now will stay in the stock location. Any thoughts or interest. Started this project a few years back and got sidetracked with live. Tell me what you all think.
 
This was discussed a few years back and it was mentioned that cooling billet heads would be an issue... don't know. Give it a shot. :)
 
Well this would be a grand opportunity to liquid cool the heads! The barrel attachment might take a little bit of development, air or liquid, but it is an interesting project.

Cooler heads would improve valve cooling, allow some higher compression, and higher operating cylinder pressures to allow turbocharging. One could replace some 360 and 540 with higher blow pressures on something like a 320.

Good luck and keep us posted!!
 
What is the motivating goal?
At 2700 RPM (or a bit more) the improvements to volumetric efficiency can't be great. Perhaps a more efficient combustion chamber or relocated spark plugs?
 
Yes it ahs been a long winter!!! As far as the attachment to the cylinder. It would be the same for now. Maybe a bolted flange later. Improvements would be a correct chamber. That is where most detonation problems with air cooled engines can be improved on. Valve would be canted for better valve to cylinder wall clearance. A correct short turn radius for better port velocity. I see places like Lycon and Sky Dynamics building some powerful stuff but it could be much better with a little technology. Water cooled out for now. Still wanting simple and light. Cooling will be no problem. Colling fins on my model are more that adequate. There is a bunch of room in cam timing that would help that problem with a correct chamber. So if I put the first set on a Pitts will I be banned for life? :)
 
Billet Cylinder Heads

LoopDLoop2 said:
Maybe a bolted flange later. Improvements would be a correct chamber. That is where most detonation problems with air cooled engines can be improved on. :)
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1. A bolted flange requires a gasket and is just another possible leak path. I'd stay with the shrunken/screwed attachment.
2. Exactly what is wrong with the existing combustion chamber shape? You are limited to 2 valves per cylinder (every air cooled engine that I know about has only 2 valves). So this limits you to a wedge or (semi)hemispherical shape. You also have two spark plugs per cylinder, therefore two flame fronts. Regarding detonation, you're probably aware that a 6" bore is about the limit for control of the flame front, end quenching etc. What are you going to change that will improve the current cruise BSFC of about 0.38?
 
terrye said:
1. A bolted flange requires a gasket and is just another possible leak path. I'd stay with the shrunken/screwed attachment.
2. Exactly what is wrong with the existing combustion chamber shape? You are limited to 2 valves per cylinder (every air cooled engine that I know about has only 2 valves). So this limits you to a wedge or (semi)hemispherical shape. You also have two spark plugs per cylinder, therefore two flame fronts. Regarding detonation, you're probably aware that a 6" bore is about the limit for control of the flame front, end quenching etc. What are you going to change that will improve the current cruise BSFC of about 0.38?
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The biggest problem is these "heads" were designed in the 40's and really no changes have been made since. The shrunken/screwed method would be best but I still believe that a bolted flange will work also. Cylinder pressure is what will cause failure and a improper tune will accelerate it. I am looking for a "simple" solution. The bore size on these engines are rather large for the valve size and there is some room there for improvement. The STR on both the In and Ex ports is sad as far as being conducive to port velocity. That is where the major improvement will be seen. The chamber changes will improve the knock threshold and allow proper timing for a complete burn. There is plenty of power to be had in a two valve head. The only thing is to remember engine speed. It is very low for the power being made. Port velocity is king. Everything else will fall in line.
 
It all sounds very interesting and would love to see what new design changes you come up with and the performance benefits.

Looks like you have a new project....

With the performance gains you project and if you are cost competitive and reliable you could very well be in the cylinder business one day soon.

Good Luck

Glenn Wilkinson
 
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