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Old January 9th 09, 12:56 AM posted to rec.aviation.homebuilt
Peter Dohm
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Posts: 1,754
Default what every boy needs - yeah seriously


"cavelamb" wrote in message
...
wrote:
what else???

Stealth Pilot


As VeeDubber has pointed out the heads are the limiting factor for HP.
The VW has other problems but workarounds for them have been found,
even if they are inelegant ones.

I've looked at and sawed up more VW heads, and sketched out more ways
to improve them, than a sane person would be willing to admit to in
public. If one insists on dual plugs and a true improvement (other
than just more cooling capacity) then I haven't been able to come up
with a solution - unless one also moves the camshaft and spaces the
lobes out to match the bore spacing. This requires a new crankcase as
well.

Doing this opens up MANY options using inexpensive off the shelf
parts. I'm thinking a split head, like Scat makes, but following the
layout of a Porsche 356 might be a good starting point?

Oil-cooled VW heads are an option I have not heard anyone talk about
for aircraft use. I've not done any math related to this option but
it seems to be a viable one. Anyone actually tried the methods used
by Porsche tuners on a VW?
========================
Leon McAtee



Fin area of the heads is only the first in a long line of limitations.

To my thinking, the next is the cylinder hold down studs (that don't
go all the way across).

The next would be valve seats (hydraulic lifters won't help there).

Valve size would have to be enlarges to let the engine breathe.

Six or eight places later comes the thrust bearings. At some output
level one would have to take power off the fat end and install larger
thrust bearings.

In the end, it makes a wonderful 40 horsepower motor.


The cylinder hold down studs have always been my first concern as well.

In the end, I completely agree that it is a great, inexpensive 40 horsepower
alternative for a single place aircraft.

Peter