so the other day im driveing my car (89 305 tpi) and i look down at the oil presure gauge and its reading zero this is after i heard a clunk and a grinding noise, so i pull over check the oil see if its topped up, its fine, hop back in hopeing it would resolve itself, drive home, pop the oil cap off and some smoke comes out,i feel around in the head by the pushrods and everything in there is bone dry, i fire the car up yesterday to move it a bit and the oil presure is reading normal so i leave the car running and open the oil cap again and there is no oil comeing up the pushrods.... isnt it supposed to come up the pushrods to lubricate the rockers and so on ? if so any ideas of what is or isnt toast in the motor?

 

Possibly failed oil pump, thats what I would guess. I would NOT run it again, because if the pump is gone, then your motor is toast.

 

its likely youve ALREADY done some damage, but pull the filter off and replace it with a WIX or PURALATOR filter ,change oil as a first test, if you don,t get oil, pull the oil pan and inspect the lower end,, bearings,rods, pickup, clearances,etc.replace the oil pump and pick-up, while your there and install it so theres 1/2" between the pick-up and oil pan floor, if you don,t the engines going to be JUNK shortly

 

What does this mean?

Your factory gauge should show very high OP at startup, then should go down to maybe 20-25 psi idling hot. Should be 50 psi or so hot, when above 2000 RPM.

If it doesn't do that, but rather goes to zero when hot, replace the sending unit first.

If it's still zero after that, don't start the motor up any more; because all you'll be doing, is shedding more metal into the oil frpm whatever is torn up inside, and making it harder to clean up and/or repair, and ruining more parts.

I'm guessing there's actually some history behind this that we haven't heard yet... like, exactly what kind of "driveing" was going on that this happened during.

Oil pumps don't "fail". That is VERY VERY rare; so rare it's not worth considering. It would be BEYOND STUPID to pull the pan and change it out because you think it "failed", without checking the bearings. It definitely is possible for the pickup to fall off however. On the other hand, running an engine with low or no oil pressure DESTROYS it, and VERY QUICKLY at that; so if in fact it has been run that way, then no matter whether the lack of pressure came before or after the bearing damage, there will be bearing damage. That's IF it actually has low/no oil pressure. Start there: figure out what your oil pressure REALLY is.

 

I just remember story on here about eight or so months back about a guy who's pump crapped on him (this was after some sketchy mechanic work though), and he had no oil pressure, but thought it would be alright to start it up and repark it, from what I remember. He got back to us telling us that he had spun a bearing and now had a rod knock, because the car was running for all of ten seconds.

 

BELIEVE IT. Don't argue about it.

If something happened to ONE oil pump because ofthen THE OIL PUMP DID NOT FAIL. Rather, the oil pump WAS DESTROYED by external forces. Specifically, it suffered from mechanical failure: where the mechanic failed to do something right.

A perfectly running motor, that's been running perfectly for thousands and thousands of miles, doesn't fit into the oil pump "mechanical failure" mode.

Likewise, a motor that spinds rod bearings because of being without OP for only 10 seconds, wouldn't have lasted long anyway. Sounds to me like the bearing was a vicitm of "mechanical failure" as well.

I have experienced exactly ONE - count it - oil pump failure, in my entire career of this hobby. And that ONE, wasn't even strictly the oil pump, but rather, something else, which killed the pump. That something else was the stupid plastic retainer sleeve that holds the drive rod to the pump. And that motor lasted for about 2 miles of driving, probably 5-6 minutes I'd guess; and the motor was completely unharmed.