Date: Mon, 15 May 1995 13:48:50 -0700
Sender: Vanagon Mailing List <vanagon@vanagon.com>
From: wabbott@townshend.Corp.Megatest.COM (William Abbott)
Subject: Overheating
Don't forget that curing symptoms can often be as important
as 'causes'- the treatment for Cholera is to replace the fluid lost
until the bodie's normal processes dispose of the disease organism.
All you have to do is give the sick person enough water, with
a little salt and a little sugar. THEN you worry about good sewage
and drinking water systems.
Bleeding is the same- first you STOP the bleeding, then you sew
up the hole. Its certainly important to ask WHY an engine overheats,
but its most important to be able to do something (add cooling, reduce
load, whatever) too!
In the discussion of overheating, no one's mentioned octane,
advance and horsepower, although compression ratio has been mentioned.
1: Remember that our aircooled beauties are really OIL COOLED!
Yes, folks, there is an *oil cooler* even in the 1100cc 25hp beetles
that were built in 1946. The question is not Oil Cooler Or Not? but
how stock to run it. Engine horsepower doubled, and then some, in
the 60 years of active development, and the factory fiddled with
oil cooling with every increase in output.
VW's factory stock set-up for type IVs is dramaticly
different from the early type 1/2. Type IV and 'dog-house' type I/II
have an oil cooler which gets its own air-stream, like a 5th cylinder,
rather than pre-heating the air going ole' #3.
2: Low octane gasoline, lean mixture, and too much advance
all create more HEAT. I've seen VW heads that MELTED THROUGH. Water
cooled cars don't have that problem. Its also true that an aftermarket
oil cooler isn't going to save your head. If you are running lean, a
high compression ratio, cheap gas or too-far-advanced spark, you may
melt your engine. Compression ratio is the product of the parts
an engine is built out of, the rest are adjustable.
Besides the above, VW engines have a thermostat regulated
flap system that modulates the flow of cooling air: If that breaks,
it can dramaticly reduce your cooling, which is why some people
remove it entirely. Without it, in cold places at least, your engine
is going to warm-up poorly in cold weather.
For my single-cab, I'm putting in a pure-stock 1600, single
port, with dog-house cooler. I'll instrument it as soon as I can
afford to, and watch the temp in different conditions. I'm going
to run Super Shell 92 octane in it. Should it run with engine oil
temp over 230c for long periods, I'll definately consider an aftermarket
cooler, which like Martha's will have a fan associated with it.
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cheers! |#######\ = \/ = /#######|
Bill Abbott |########\ =\/\/= /########|
'70 single cab |#########\ -__- /#########|
'93 Corrado |##########\ /##########|
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