A pocket in the piston would help with regard to the location of the squish band but that means another custom part. I'm thinking that with a good chamber designed for fast burn, even with a flat piston, 10/1 may be realistic for a VW aircraft engine. We know a LOT more about this than when the VW chamber was designed.If you were to fix everything, you would close up the open chamber some and add a pocket to the piston, for equal compression, matching the head for better detonation control on low octane fuel.
I wonder if a combination of casting and efficient "MCM" (manual controlled machining" ) is the right mix for this type of relatively small batch production. Cast the basic shape of the head with all rough ports and the rough combustion chamber, use carbide saw kerfs to make a large number of generous fins, and drill as required to finish air passages "under" ports and other places where they can't be sawn. With some smart jigs it could probably be fast work not requiring expensive machines or highly-skilled labor. Machining is required in many other parts of the head anyway, this would be an extension of that.I imagine CNC might be a bit expensive unless it was your own machine.
I like that termefficient "MCM" (manual controlled machining"
All I promised was Vaporware. Delivered! See post #65. and 4 cyl version below:We've been yammering on about this for two weeks already. Where are these long-promised new heads? What is the hold up?
Well, I can't argue with that. Pretty neat. Is your cylinder head wider (from edge of top fins to edge of bottom fins) than we see on most aftermarket heads? You've got lots more fins, and they look deeper than usual. Regarding the rocker arm shaft--one per cylinder or one per side (exiting between the two valve covers)? More seals = more leaks. I do think that a unitary cover (front and back cylinder) will probably be more popular.All I promised was Vaporware. Delivered! See post #65. and 4 cyl version below:
Yes, just Napkin Grade at this point. Don't let the pretty? pictures fool you.Well, I can't argue with that. Pretty neat. Is your cylinder head wider (from edge of top fins to edge of bottom fins) than we see on most aftermarket heads? You've got lots more fins, and they look deeper than usual. Regarding the rocker arm shaft--one per cylinder or one per side (exiting between the two valve covers)? More seals = more leaks. I do think that a unitary cover (front and back cylinder) will probably be more popular.
There'd be a greater market for the 1/2 VW if . . .I'm also trying to consider if there is a need for 1/2 and 4 cylinder versions. If this ever got to the real hardware stage I think there might be more of a market for 1/2 VW heads? There would be a better profit margin/cylinder.
No one can say what makes another person's banana dance--a mystery.Why isn't my banana dancing in post #89 :dis:
This for me that would be going backwards down the road. I started out with that idea - a new version of the Mosler - and it kind of mushroomed into a full re-think of the 2 cylinder VW based engine. But I decided there wasn't enough of a market. Then about a year later along came the O-100 project. There is too much overlap on that project for me to reconsider my old project....you just went ahead and casted/fabricated an optimized 1/2 VW >case< while you are going down this road. << >> by eliminating stuff we don't need in the present case, I'll bet you could save enough weight
Do have access? - no. Will have? - probably not unless I farmed this part of the work out., do you or will you have access to a moderate size VMC with at least a CAT40 spindle?
FW - You have enough evidence now.....I don't know if this is 'on topic' or if I'm just ranting but... we've been trouble shooting a compression problem on a friends VW and I was shocked by what I saw. I won't mention AeroVee's name but these are the absolutely ugliest head and cylinder castings I've ever seen!
?? Why would water/glycol be needed? Oil alone will do the job in this case, just pump a lot of it through the heads using a high volume/ low pressure stage added to the existing pump. A second system, separate radiator, etc is a lot of weight.No need to invent something that's been successfully done by others. Copy the Rotax 912 head design and attach a small water pump on the pulley or flywheel end and go flying. A combined oil/water cooling is a proven method. Thousands of rotax engines plus hundreds of thousands of BMW heads. They never need adjusted, no dicking with valves or re-torquing them. Original VW was designed to produce 32 hp. When you start talking about 80-120 hp the heat will need to be ported away with liquid coolant and oil. You can leave the rest of the motor as it is.