4.0 Oil Pressure

[FUNKYTEE5]

Though there is no question I would prefer a cast iron pump, aluminum pumps are fairly common for OEM applications. I'm sure it's because of lower machining time, and longer tool life when machining. The way a oil pump is built the majority of wear should be between the steel cover plate and the steel gears. There should be plenty of clearance between the aluminum housing and the pump gears. Unless you pick up a fairly large chunk of crap (which should be screened out by the pick up screen) aluminum should be fine and shouldn't wear any faster than an Iron pump.

B-loose

I agree! But my pump that I replaced was chewed up pretty good. That wear could have been a result of the previous owner's habits? I keep my oil clean The drive gear was eating into the housing due to the shaft bore being sloppy. The specs for gear side clearance that I found were something around .004" mine was like .008" and not consistent. The drive gear shaft also had .0015-.002 ridge in it. Maybe it's just a reject oil pump? But i've heard accounts where people have had them go downhill around 150k. Heck that's alot of miles regardless. The great thing is that i've still got super oil pressure, tight rings, no piston slap, and it's still a great runner with that many miles on it!

Funkytee

 

[Bloose]

If the shafts wobble in the bore your gonna have problems. That's why an iron pump is superior. But for the OEM's 150K is pretty good.

B-loose

 

[Mike@Accurate]

While on the topic of wobbly shafts & such. I'd have a look at the distributor drive gear. I have seen bad gears take out oil pumps. Sometimes you can see the distributor wobble when the engine is running. The oil pump shaft (screwdriver slot) can't take the mis-alignment and one (or both) ears break off. Usually this resulted from a new cam and old gear, like a new ring gear on an old pinion, and the gear wiped out. The teeth ride up on the cam gear and eventually busts the pump. Pump wobble could have the reverse effect. It all goes around together, MIKE