One more oil pump question: gasket or not Options

[bkrantz]

I have a Shadek pump adapted for Type 4 (which I know some people don't like). The first time I installed the pump cover I did not use a gasket, just case-sealant. For the second time around, should I use a gasket under the cover?

[Superhawk996]

As above - I’m a believer in gaskets for something that has high pressure oil behind it.

I know there are those in the VW community that say no gasket. My understanding is that tribal knowledge largely came from people having used aftermarket gaskets that were way too thick which caused low oil pressure due to too much bypass due to the thick gaskets.

The correct gasket is about 0.003” thick. If you lap the oil pump case so that you have no end play on the gears - you’ll gain 0.003” of end play and proper bypass with a gasket installed.

If you already have .003” end play of the gears without a gasket, adding a 0.003” gasket will double the end play. Even at 0.006” end play it won’t be terrible for oil pressure but isn’t optimal. The problem occurs with some of the aftermarket (or home made) gaskets that are more like 0.010” thick which leads to way too much oil bypass.

Hope that helps make a educated decision on which is right for you.