leaky oil pump

strato1 · #1 (**permalink**) 07-17-2008, 02:14 PM

I got my '55 truck on the road finally and have been putting a few miles on my '62 292 Y bock motor completely rebuilt and running fine but not broken in. When i left the shop a coupe days ago i noticed the oil pump looked a little wet. no biggie. The other day in traffic it was smoking pretty bad (this is a new pump but put on about a year ago) so the pump body was leaking couldn't tell if it was from the block to pump or pump to pump cover gaskets or both. I tightened them up in a parking lot and the pump cover bolts each took about a 1/4 turn.
Driving home the thing looked like it was on fire or running some type of smoke screen. I nearly pumped the thing dry and oil is splashed up on the firewall, and all down the underside. Is this just a bad gasket or something more sinister? Oil pressure at idle was 25-30 and highway speeds at 40 to an occaisional 60 psi but no more than 60.

I drilled the valley cover and put in a pcv valve where the road draft tube used to reside, and am using the stock oil breather. Do you suppose I'm just pushing too much pressure in the crank case?

Also the valves were getting pretty noisy, but they have not been re-lashed since innitial build. I was wanting to get some mies on it and then re-set. and I suspect that I may have the timing a little too off becuase you can occaisionally hear it firing in the headers like it is hitting late.

46yblock · #2 (**permalink**) 07-17-2008, 05:23 PM

First try and pinpoint where the oil is coming from. Sometimes the spin on oil filter adaptors leak, either from a bad or improperly installed gasket, or the pressed metal adapter itself gets sprung and doesnt put enough tension on the gasket for a seal. I have had that happen twice, and wish someone would machine out a billet aluminum adaptor that was sturdier.

Valve cover gaskets can leak and if at rear of head can make it look like the oil pump is the culprit, as the oil flows down in that vicinity.

If your oil pump is a gerorotor type, there could be one of three problems. Leaking pump to block gasket, twisted cover to pump body gasket, or a casting defect. On the casting issue, my first Y startup resulted in a pouring of oil from the pump. It was coming from between the cover and body. Farted around for a week trying to get it sealed and finally noticed a casting defect. There should be a thin amount of material between the groove that the gasket sits in, and the cover bolt hole. At one of the bolt holes the casting was such so that the hole extended into the groove, and the gasket would basically blow at that point.

As for crankcase pressure, it doesnt sound like there is oil blowing out the filler neck. With motor running there shouldnt be anything visible coming from the filler.

strato1 · #3 (**permalink**) 07-18-2008, 08:21 AM

Thanks for the quick response. I guess what I need to do is degrease the truck and pressure wash it and then drive it a bit and look at the spin on filter adapter.
When I built the truck I broke in the cam but never put any miles on it. Then it sat for a long while- nearly 8 months maybe more. Got back to it got it running, and had a leaky rear main seal (my fault I forgot to put those two pins in). Put a new filter on it at that time. Got it on the road just to test it, jut going up and down the street by my shop, no more than a mile total over several months, but I would crank it at least once a week and let it run and would back it in and out of the shop.
This is the first time I actually got it on the road, and I drove it several miles over several days. On about day 3 or 4 is when this started. I'm out of town and was visiting some friends. On the way back to my hotel it drained 4 quarts out and zeroed the oil pressure gauge but I immediately shut it down, went back the next day put 4 qts in it (dipstick read nothing) and it cranked up and I loaded it on the trailer where it sits until I head home . I hope I didn't damage the motor. Didn't sound bad on the last start up.

So do you suppose the oil filter adapter could have worked its way bad? I did notice the pump was a little wet before i left the shop. also there is now a lot of oil on the trailer, but it could be just dripping off the truck itself. The suspension is wet, the transmission, it really bathed the thing in oil.

Also the oil is way high on the firewall, so it very well could be the valve cover gaskets. If that is the case then top end oiling is definitely not an issue!! At one point before getting it on the road I did pull the valve covers off just to check the top end and just put them back on without new gaskets. But usually a bad valve cover gasket is a long time slow leak, Ive never seen a severe case.