HELP!, Low oil presure

[DOREYV8]

I took my 400se on a track day last month, and the oil pump gear broke. I have replaced this and run the engine, everything is ok but when the oil gets hot the oil presure drops down to around 5psi at idle. it never used to get this low before. ANY IDEAS.
THANKS STEVE

[jchase]

I would plastigauge the big end clearances if I were you, and check the bearing inserts for signs of scrubbing, your lack of lubricant may have damaged the bearings. Do you notice a subtle clunking noise at idle ? I presume that the EXACT same type of oil was replaced in the engine after the oil pump replacement? if not, it is probably a viscosity problem with the oil, you might consider choosing a thicker weight for the hot viscosity number - ie change from 10W30 to 10W40.

A friend's mini had super low oil presure, and it turned out to be totally shot mains and big ends, the oil was full of silver and gold glitter! The engine was totally ruined, top and bottom. The symptoms started with low oil pressure light when hot at idle, which she ignored, then finally the light just stayed on, even when the engine was cold.

Hope this helps.

-Jim

[19560]

What did you replace Steve? Did you face the cover plate?

[DOREYV8]

I only replaced the two gears. What do you mean by faced the cover plate?

[19560]

DOREYV8 said:

I only replaced the two gears. What do you mean by faced the cover plate?

The gears tend to wear away at the cover plate. If you only replaced the gears then the worn plate could be letting oil seep by. To face the cover plate is to have an extremely light skim to just remove the shadow left by the old gears. It's amazing what thin gaps oil can pass through.

[350matt]

Apparently you can get a shim to avoid having to skim the plate - anybody know of a supplier?

Matt