Date:         Sun, 14 May 1995 12:19:57 -0700
Sender:       Vanagon Mailing List <vanagon@vanagon.com>
From:         eugp@uclink3.berkeley.edu (Eugene C. Palmer)
Subject:      Re: Add-on Oil Coolers

>Christopher Bridge writes:
>> 
>> Another Chris writes:
>>
>> >I have found that an external cooler won't help overheating, just delay
>> >reaching overheated, by virtue of there being more oil to heat.
>> >I have also found that an oilcooler on a new strong well running engine is 
>> >a waist, takes motor longer to warm up, leaks. hoses in the way.
>> >Most of the stuff in the mags are there because they sell, they don't give 
>> >a ship about your engine.
>> 
>> I couldn't agree more.  I especially like what the author of the "high 
>> performance" section of Muirs book says on the subject.  He says something 
>> like: " build it right the first time, and you will not have to cover up 
>> your mistakes with coolers and .....".      
>
>Well that all sounds good, but how come my engine overheats all the time?
>I rebuilt it with all new parts, took my time, put in a Melling oil pump,
>and it will overheat if I go up a steep grade, or just try to maintain 65
>on a long strech of highway in warm weather.  I don't know what else to do,
>except assume that the engine cooling system was "underengineered".  Also,
>my camper is several hundred pounds heavier (and 24" taller) than those VW
>engineers designed the motor to handle.  For now, I have to keep a close
>watch on the pressure and temp and back off when it starts to run hot, but
>I am determined to put in an external cooler eventually in hopes of solving
>the problem.  I hear there's a puke-eggnog parts van up in the Bay area
>somewhere, anyone know where to find it?  =)
>
>-David

Volks, 

Build to 6.7-6.9:1 compression ratio for the air-cooled engine.  Engines I
have built at this ratio run cool, strong and have so far lasted.  They hold
their valve settings for easily the 3000 mile tune-up interval, and barely
need adjusting then.  Stepping up to even 7.1 or 7.3, which is about what
stock was, raises oil temps to the point where they pass 210 degrees working
hard on the road.

If you are considering re-using an old case, look closely at the bearing
saddles, _any_ indication of 'pounding out', or metal compression where the
case retains the bearing means oil will leak, perhaps at a pronounced spray,
through this area.  Oil temps will be higher and pressures will be lower,
rod and main journals will wear sooner.  Less oil will be available to the
valve train.  The metal in this area has been severely fatigued and line
boring it will not restore the metal itself.  The AS21 case now being made
is stronger than the AS41 case most of our engines began with.  Get a new
case.  I have no type 4 experience, but presume the same general rules apply.  

The most deadly combination for a 'rebuilt' engine is for the bearings to be
sloppy (anything less than solidly crushed)in their saddles, the oil pump to
be sloppy in the case, and the compression to be stock, or high for stock
(big bore pistons or flycut heads).  No amount of coolers, pumps, new heads,
etc. will save that engine from overheating and early failure.

Using a 30 mm oil pump and/or thicker oil will improve a bad situation, but
is not addressing the issue directly.  I did this on a rebuild with worn
bearing saddles and the engine still runs well, and cool, but it must be
watched closely.  A couple people have mentioned oil lights coming on at
seemingly intermittent, or unusual times.  Don't dismiss the oil light, it
is not likely to malfunction unless the wiring itself is funky.  If the oil
light is on, there is no or almost no oil running in the bearings.  The cast
iron melling pump might not expand at the same rate as the case and could
leak from the all important case to pump area.  This is where the pump
develops it's suction to the sump and, if compromised, will certainly cause
low oil pressure and volume. 

The 1967 microbus was rated one ton, presumably this means you can drive it
with a one ton load.  I think buses built after that are also one ton.  When
I drove the 6.7 CR bus on the freeways and up hills with over 2500 pounds in
it, it didn't overheat.

>For under $30 I eliminated all hose clamped lines, and replaced them with
>High pressure hydraulic line using AN-8 (used on A/C) fittings and swedged
on >ends.

Sounds great, an excellent alternative to Bergs brittle stainless steel.  

I can hear some people saying "Oh no, a Bergie"  I have no great allegiance
to Gene Berg, but I take what I can use and what I have experienced myself.
I have to agree with what someone said awhile back that "Bergs hurt me more
by what he hasn't said, then by what he's remembered to say"  Sometimes it's
inevitable that information be left out, unfortunately, that information is
occasionally crucial.  Homebrew VW's have their pitfalls.  On the other
hand, his catalog is still my VW bible, and his crankshaft is in my engine.

Eug,
'71