Re: Oil Cooler: Type 3 Engine

["Dan Hoopes" <dan@ewed.net>]

With all this talk about pressures, it makes me wonder what exactly the
pressure should be.  I have a pressure sender screwed in to where the old
pressure sensor is on the oil cooler that goes to a VDO gauge.  What is the
optimum pressure for: running at about 3500 rpm and for idle?
I also have an oild temp sender bolted into by sump plate.  What is a good
running temp.  At what temp should i pull over and let it cool?
Thanks

Dan Hoopes
dan@ewed.net
'67 Square (Stanley)
'73 Thing (Nameless)
'64 Bug (Mutley X Baron)

----- Original Message -----
From: Jim Adney <jadney@vwtype3.org>
To: <type3@vwtype3.org>
Sent: Monday, June 28, 1999 4:19 PM
Subject: Re: Oil Cooler: Type 3 Engine


> On 28 Jun 99, at 10:02, Per Lindgren wrote:
>
> > Well, I cant be totally sure, but the catalogue from the shop said it
was 12 mm
> > oil galleys in the case, I am not sure if that applies to the oil cooler
holes.
> > I do not want to disassemble the case to find out ;-)
>
> I guess I never heard anyone describe a case by the dia of the galley
> holes, so, yes, they could be 12 mm, with 10mm oil cooler holes.
> Actually, IIRC, the 2 oil cooler hole bores are slightly different
> sizes so I'm not really sure what measures 10mm, This is just what
> "everyone" describes them as. I believe the holes in the actual
> cooler are 10mm.
>
> > The original cooler for the car is 311 117 012 B, on the T1 oil cooler
in the
> > car, the number is not visible. As far as I can remember, it was totally
> > identical, except for the pressure sender6(ó
> Okay, that's right, you don't actually have the type 3 cooler. The
> type 1 cooler of this shape was only made in the 10mm version.
>
> > The initial problem I had that lead me to replace the cooler was low oil
> > pressure at idle, with a totally rebuilt engine. I had a new case, new
camshaft,
> > new oil pump, new relief valves and springs, and new bearings. Even a
new oil
> > strainer. All other parts were measured and within specs. I tried to
replace the
> > crank, new bearings (again), several pressure senders, pressure meter,
different
> > oil cooler, you name it, I tried it. The only thing I didn't try to
replace was
> > the oil pump (from Brazil), but as the car is undergoing a very slow
resto, it
> > has not been done yet. The oil is 20w-50 Castrol GTX. Any ideas, anyone?
>
> Two thoughts:
>
> 1) Did you realize that our pressures are always "low" compared to
> what most engines measure? In other words, did you only start to
> investigate this carefully AFTER the rebuild?
>
> Part of that is just due to where the pressure is measured: after the
> cooler for us, before the filter for them (I think). Part is due to
> the fact that we just do with less pressure. This is consistent with
> the fact that the only pressure the engine needs at this point is
> that necessary to get the oil to the bearings. The actual pressure
> necessary for lubrication is generated hydrodynamically within the
> bearing by the motion of the journal within the bearing--this
> pressure is NOT dependent on input pressure, although it IS increased
> by FLOW in and decreased by wide clearances that increase flow OUT.
>
> 2) In many cases, using higher viscosity oils to boost measured oil
> pressure just serves to reduce flow to the bearings and to maximize
> the amount of power that is used by the oil pump. Both of these
> things are counterproductive.
>
> I went through a long period of being fooled by both of the above
> problems.
>
> Jim
> -
> *******************************
> Jim Adney, jadney@vwtype3.org
> Madison, Wis“~£ZUSA
> *******************************
>
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