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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 sender hole. 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 -œ& low 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, Wisconsin, USA ******************************* ------------------------------------------------------------------- Unsubscribe? mailto:type3-request@vwtype3.org, Subject: unsubscribe