Earlier Joel had posted the compression ratios for Vanagon air-cooled and
water-cooled engines. I remarked that the air-cooled ones seemed somewhat
low. They DO seem low compared to what Chilton's reports for all VW
engines from 1965 on: ie the early  A type 36hp engine and the 25 hp engine
had comp.
pressures of 85-114; but after 1965 the pressures range from 107-142 (H
series) to 121-142 (G series) and 135-164 (R series). Since the
manual only goes up to AD
and AE series engines (all 1600cc's), I don't know if pressures gradually
decline as
engines get bigger in size...One possibility is that the lower pressures
allow the use of  cheaper low octane fuel and this may have been a goal of
the later engine design. Didn't some after market rebuilders use dished
piston heads to acheive lower pressures....? Anyway when we took the Westy
in to a mechanic to have the engine checked out before we bought it, he
suggested a rebuild because two of the pistons were at 90 psi....DC

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David Carment
School of International Affairs
Carleton University
Ottawa, Ontario
K1S 5B6
voice - (613) 788-2600-6662
fax - (613) 788-2889
Email address: dcarment@ccs.carleton.ca
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