On Jan 29, 2:29 am, "oilsardine" wrote:
compared to the '85 HP aircraft cylinder head' the VW head doesn't look so
bad after all...
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Looks can be deceiving.

The maximum output of the carburetted 1600cc VW engine was the 1971
model which could produce about 57bhp... for about ONE MINUTE.
Maximum SUSTAINED output (ie, CHT of 450F) was about 44bhp under
Standard Day conditions. At that level of output you could expect the
exhaust valves to drop out of spec after about 200 hours. NOMINAL
output of the 1600VW was about 15bhp, which allowed the exhaust valves
to survive for up to 1000 hours (although 600 t0 750 was more the
norm). After-market 'hot-rod' heads do even worse since they have
less fin area. Volkswagen dealers commonly swapped-out worn heads
without bothering to inform the owner, other than to list their
replacement in the 'OTHER SERVICE - AS REQUIRED' block on the work-
order.

To understand why the VW head does so poorly simply compare it to the
early 1500cc (85hp) Porsche heads. Then compare those to the Corvair.

-R.S.Hoover

PS -- Here in the States many VW owners insist their vehicle NEVER
required anything other than normal maintenance when in fact,
examination of its service records usually shows periodic replacement
of heads, carb, distributor, clutch and oil pump with rebuilt units,
all for a nominal charge, when the vehicle was brought in for service.