What keeps the pump gears from resting on the oil pump cover after installation?

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1970 VW Bus- converted to a 110hp w/a PG. Now with electronic ignition!
Kansas City, Mo

Nothing. But it is the "oil pump" and thus the gears are well lubricated.

Nothing. An engine with a 100,000 miles will probably have a slight wear pattern on the cover.

Most people “sand” the cover flat and reuse it.



Edited 1 time(s). Last edit at 10/29/2020 07:08PM by RobertC.

Too thin of a gasket for no clearance wouldn't be good.

Jim Brandberg
Isanti, MN
CorvairRepair.com

Its the hydrodynamic film that lifts the gears off of the bottom... the movement of the gears wedges the oil between the gear and the pump cover, just like it does between the gears and the aluminum case, and of course, between the gears themselves. The reason theres so much visible wear on these surfaces relative to the rest of the engine is because it is the only part of the oiling system that is exposed to all the junk in the oil before it goes to the filter... kinda like pumping lapping compund.

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Kevin Nash
Friday Harbor Washington
63 Spyder, Daily driver, EFI read about my project here: [corvaircenter.com]
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engine less 62 Spyder
Canadian 64 Monza Parts car

Before "sanding" the cover to remove any wear do a plastigauge!!

Someone posted once the milled surface perpendicular to the guide and drive shafts is NOT always exactly perpendicular. I found this to be true. On engines with minor wear on one side of the oil pump gear cover plate the wear actually made the both gears have the same distance to the plate.

I discovered this when I did a plastigauge to check the gasket. One gear was too tight and the other was too loose. I turned the plate 180 degrees (wear pattern moved to other gear) and BOTH gears then had the SAME plastigauge tolerance.

Note the wear was very minor, not what you'd find with excess wear caused by a lack of oil changes!

Thanks everyone.

Was just curious as I had the gasket kit from Clark’s and as it turns out, the thickest gasket is the only one within specs.

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1970 VW Bus- converted to a 110hp w/a PG. Now with electronic ignition!
Kansas City, Mo

So, were you really asking what keep the gears from BINDING (not "resting") on the cover? I was assuming the clearance was already properly set and you wanted to know what kept gravity from causing the gears to touch the cover.

Nope- question was “what keeps them from resting on the cover”

Question occurred to me while changing the gasket

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1970 VW Bus- converted to a 110hp w/a PG. Now with electronic ignition!
Kansas City, Mo