Oil leak Source?

[Rob M.]

Okay, I have oil dripping (small amount) off the bottom of the fuel pump and on to the A-arm. Very annoying. What would be the most logical source of the leak? I believe the valve covers are seeping a little, but don't believe that to be the source. Suggestions?

FWIW - The motor is believed to have never been out of the car, at least according to the judges at the regional. It's a 327/300 no power steering or brakes.

Thanks

[Michael G.]

Re: Oil leak Source?

Rob,

Engines I've dealt with in the past was a common issue for the plate which mounts to the block (fuel pump mounts to plate) to be leaking. As the fuel pump mounts to this plate could be seeping oil as well.

Michael G.

[Rob M.]

Re: Oil leak Source?

Thanks Michael.

I did change the fuel pump (rebuilt original) about a month ago. The plate that it mounts to could be the problem. I will have to clean it up and then really look at it. I didn't think to change or check the mounting plate when we changed the pump.

Thanks,
Rob

[John H.]

Re: Oil leak Source?

Rob -

If the topmost of the two 3/8"-16 tapped holes on the front of the block right around the corner from the fuel pump doesn't have a bolt in it, you'll have an oil leak from the fuel pump pushrod passage, and the first thing it'll hit is the fuel pump.

[Rob M.]

Re: Oil leak Source?

John,

Thanks for the post! That is certainly not something I would have even have known or thought about checking.

Again, thanks!

[Stuart F.]

Re: Oil leak Source?

Those tapped bolt holes are there, as I'm sure only us old timers know, to mount the front engine mounting brackets on 55 thru 57 Chevy's. The one John is referring to into the pump rod chamber, can be used with a special spring loaded bolt to secure the pump rod from falling down while changing out the pump. I have such a bolt that I bought for that purpose (center is drilled out and spring inserted), but I have found few Chevy V8 applications where I could use it. Seems Chevy found lots of other things to bolt to those hole over the years, such as various accessory brackets.

A number of engine applications I have seen do not have a bolt in that tapped hole and did not leak oil from it. If that is your source of oil leakage, I suspect the pump rod is worn excessively allowing more oil than is needed to lubricate the rod accumulating in the chamber - or something related to that such as excessive oil pressure, etc.

Stu Fox

[Clem Z.]

Re: Oil leak Source?

if the oil is coming out the hole on the top side of the pump the crankcase oil return hole in the block could be restricted and the oil is not returning to the crankcase fast enough

[Stuart F.]

Re: Oil leak Source?

Rob;

I think what I stated/described and Clem's clarification pretty well tells you what you need to know. Thanks to Clem for clarifying why oil should not be coming out of that tapped hole - even w/o a bolt in it.

Stu Fox

[Jim T.]

Re: Oil leak Source?

My original owner 1970 Corvette's engine was destroyed on the first day of ownership (oiling problem) within minutes leaving the dealership after delivery.

The dealer installed CE engine did not have the short bolt installed in the replaced short block.

I did not discover this fact until June 6, 1988 when I replaced the original fuel pump that had given me 18 years and 128,905 miles of service.

I had never noticed any oil leaking or seeping from the bolt hole. I did install a bolt, a short one. Used a long bolt to retain the fuel pump rod up to install the new fuel pump.

[Rob M.]

Re: Oil leak Source?

All,

Thanks for the lesson and I'll have to check it out. My uncle thinks it's coming from the front main. We'll see. Old engine with so many possibilities. If it were perfect, I wouldn't be learning anything.

Rob