How to structure the Oil Pump in a buick v6 can be a bit of challenge if you read various web pages. Should you use a high volume oil pump or not (the high volume oil pump is simply larger gears and a spacer to accommodate those gears)? On the 225 v6 the general answer seems to be ‘no’ unless you drill out the oil holes for the middle two main bearing holes (these are smaller than the outer ones according to what I’ve read).
The 1980 and 1981 3.8L v6 engines that I have both came with the high volume pumps. After doing research, I couldn’t get a clear answer on how good these pumps were for these later model engines. So, I turned to TA Performance to see if I could get an answer. They said using the high volume pump was fine, but recommended I use a variable pressure controller (in the pic above, you can see the old spring and nut sitting in front of the new double-nut & spring that’s already installed) and a hardened steel plate that sits underneath the gears to reduce wear (seen in the pic to the right).
I installed everything, but discovered that the gears are too tight, so they don’t spin properly (you can test this by taking out the distributor, sticking a screwdriver into the oil pump drive gear, and turning). Therefore, I’m ordering a set of shims from TA Performance to fix the problem.
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