Date: Tue, 6 Jun 95 16:32:41 EDT
Sender: Vanagon Mailing List <vanagon@vanagon.com>
From: dcarment@ccs.carleton.ca (David Carment)
Subject: Vanagon gauge update
On Saturday, we departed for Montreal for a 200 mile roundtrip for
Ottawa. This was the first first chance to test the effects of the
following at sustained highway speeds:
(an 82 Westfalia)
15W50 Synthetic;
Newly installed Oil temp gauge (pressure and head temp gauge previously
installed);
Oil cooler thermostat (2nd oil cooler previously installed w/out therm.);
Oil cooler fan w/ switch;
Engine flaps thermostat connected in hot weather (usually a winter only item).
Here is what I expected: cooler head temps, overall higher oil pressure
cooler oil temps ( all based on claimed benefits of synthetic).
Here is what I found:
1) trip to Montreal; 17-18C (68 F) slight tail wind; constant rain, 60-65
mph av. speed on highway:
head temp: 375F (325-350 is the norm);
oil temp: 180-195F (215 is smack in the middle of the gauge);
oil pressure: 35-40 psi;
2nd cooler fan did not come on once.
2) trip back to Ottawa; 25 C (80ish), slight head/cross wind, 65-70
highway speed).
head temp: 375F
oil temp: 190-210 F
oil pressure 30-35 psi
fan on constantly at speeds above 60 mph.
After shut down the fan run for another 10 minutes and the oil temp
climbed to 220F before it was cooled off.
What can I conclude from this:
a) synthetic is less impressive than i thought it would be - its benefits are
probably best realised at startup and in very cold weather; Synth does
tend to shed its heater quicker at cool down but the 50 Weight seems to
thin for really hot days. Perhaps mixing dino with synth will yield better
results, or maybe a single grade 40W?
b) head temps are hotter than normal and this may be due to the thermostat
for the flaps being hooked up constantly. I have since disconnected the
thermostat and "wired" the flaps fully open. This may lead to different
results;
c) oil temps look good and i think this is the result of the 2nd cooler;
when the fan switches on the oil does not go much above 200F (can't say I
like it running constantly though- it may be a function of the lousy cooler).
d) I think the oil pressure gauge is giving false readings (at least i
hope this the case.) Why? Two reasons. After coming off the highway the
gauge read 5psi at idle but no red light (set to come on at 7-10psi). The oil
temp (assuming it is
accurate does not always seem to jibe with what would be expected at the oil
pressure gauge. For example, oil temp will read 180 and oil pressure might
be 50 psi. Once temps go above 190, however oil pressure tends to fall on the
wrong side of 40psi but does not deviate much no matter how hot the oil gets.
This morning I installed a HD oil pressure relief spring. It is almost
twice the length of the normal spring. I thought this might result in
higher pressures all around. The result? 10 psi at COLD startup (normally
60 pi-70psi) and no more than 30 psi with a rev of the engine. I took it out
assuming that the spring was so strong that it was forcing the valve to
severely constrict the flow of oil.
So, what can i conclude? Be wary of the oil pressure gauge (VDO) as the
sole indicator of engine performance, Keep an
eye on the oil temps and head temp. and expect everything to get much
hotter when speeds are 60 mph or higher. Synth is good but not a panacea.
Don't expect it to solve any problems, real or perceived.
I should add by the way that the van has never driven better and would
have easily gone above 75 had it been pushed -
David C.
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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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