Dougs951S

Has anyone ever rebuilt an oil pump? I've got a good low mileage one from my 951 motor that grenaded, and a spare pump with more than double the miles on it. I'd like to use the lower mileage unit but i'm concerned it's full of metal contamination or may be internally damaged. Has anyone taken one apart and rebuilt or cleaned it?

V2Rocket

There's only 2 parts in the pump...so easy enough to clean.
But they don't really wear out. Its the best-lubricated part in the whole engine

Dougs951S

blue loctite on the fasteners in addition to the flange sealant on the insert?

Dougs951S

Also is the black front seal available anywhere?

thanks for the pic

SloMo228

The one tagged "Main Oil Pump Seal" in the image above? Those are readily available, normally they're called the front main seal or front crankshaft seal.

tempest411

Definitely use an impact driver to get those two screws out.

Dougs951S

Thought it looked like the same diameter as the front main. Its stuck to the pump on the unit that came from the 951 and without looking at my spare I assumed it was a seperat seal from the front main.

Van

Make sure you buy a new drive gear. Rubbing against the seal over time wears a groove in it. There's also an oring (not pictured) that you'll want to replace.

For the oil pump it's self, Loctite 574 isn't "blue", but rather it's an orange anaerobic oil sealant.

The gears in the oil pump are different thicknesses for different versions... Make sure you don't mix and match the thicknesses - that won't work.

Dougs951S

Van, I'm actually using loctite 518 in place of the 574 (on the pump, as well as the balance shaft covers and the crank girdle), its sanctioned by the FAA as an acceptable replacement and if it's good enough for aircraft, it aught to be good enough for my Porsche.

when I mentioned blue loctite, I was referring to the fasteners on the back of the pump, asking if they need to be reinstalled with thread locker.

Can you explain a bit more about the pumps for my own education? I'll only be taking one unit apart so no danger of mixing parts, but I'm curious; is that a year related thing? Any performance difference between different "versions" of the pump?

I'm planning on putting an 85.5 NA pump on my 951, but I might use the 951 pump if I rebuild it. Any danger in having a mismatch between the year of the pump and the year of the block or will pretty much any combo work?

KevinGross

The 518 should be fine. If you can catch your fingernail on a groove worn by the radial oil seal, as Van suggests replace it.

Van

I don't know the cut-over year - if it was for 85.5, or for the '86 turbo, or the '87 turbo... But the later pumps have a thicker gear set (by 2mm) so the volume in between teeth is larger, making them higher displacement - which is a good thing. That might have been a change for the turbo... or it might have been a mid-run change to try and reduce the #2 rod bearing oil starvation problem...

So, I'd use the later pump - assuming the gear teeth aren't scored up.

I once, accidentally, put the early (narrower) gear set in a late (deeper) housing, and for the life of me, couldn't figure out why a new engine couldn't make oil pressure (just cranking it over - not starting it). Tried priming them pump 10 ways to Sunday - no oil pressure. Decided to take the pump off, opened it up, and instantly realized my problem! Hard to make suction when there's a 2mm air gap between the moving parts!

Voith

Just did mine so few pictures in this thread won't harm.

michaelmount123

Quick tip:
Lube the oil pump gears with white grease and it will pull oil pressure quickly on initial start-up.
MM

Voith

Thanks. I've actually read your comment about this in another thread but since I don't have any white grease I used EP 0 grease.

Voith

Less is more when it comes to 574. I've actually glued the outer pump rotor to pump insert and spent two hours getting it all apart and clean today. PITA.

Anyway take #2: