Problem with oil in my 350 Olds...

[84Hurst/Olds]

Ok well I changed my oil roughly 2,000 miles ago. I was going out of town today, and decided to check my oil. I was a quart and a half low. If I park on concrete, I have no oil leaks anywhere on the ground. I never see any blue smoke coming out of my tail pipes. So it doesn't make much sense to me. Its not a huge problem, but I would like for it not to lose oil.

The car is an '84 Cutlass with a '68 - '70 350 Oldsmobile engine. I had a friend of mine rebuild it for me a couple years ago. It was pretty much a stock rebuild. The block was bored .030 over, and the crank was turned 10/20. Theres a little comp cam in there, with a stock intake & exhaust manifolds. I have put about 12,000 miles on the motor since then. It seems like there has always been a slight problem with the car losing oil somewhere. If I let things go for 3,000 miles, it will only have 3 qts left in it.

I did have a problem all of a sudden about six months ago. I was stopped at a traffick light, and started smelling a lot of burning oil. The car was smoking, and I got home as quick as possible. Oil was pouring out of the dipstick, running down, and hitting the side of the motor. I ended up replacing the pcv valve twice, and put a breather on the oil cap, and valve cover. Is this a common problem with Olds motors?

I just want to know what my possible problems are.

Thanks

Mitch

[84Hurst/Olds]

If it matters.... I run Castrol 10w-30. Maybe I should run a little thicker oil? I'm not sure.

[88hurstolds]

That is not a common problem with Olds motors, did you install a high volume oil pump?
Sounds like a serious problem... What does the oil look like when you drain it? Does it smell burnt or is really thick?
Oil could be getting burned up in the engine itself due to too close of tolerances in the bearings.
It may not be overheating but getting really hot at the bearing surfaces and burning up oil.
Also check the oil drain back gullies, they could be clogged and building up pressure in the crankcase, in this case to an extreme which is unheard of... I would pull the valve covers, burnt oil probably has built up so much that its clogging the vent/oil drain back passeges.

[84Hurst/Olds]

Well the oil pump that came in my kit was a standard volume Melling. I had the valve covers off a few months back, and everything was nice and clean. I will pull them off in a few days and make sure. The guy who built it for me is a Chevy mechanic, but said he had done Olds motors before. What exactly do I look for when I take off the valve cover?

[84Hurst/Olds]

It doesn't push oil out of the dipstick anymore. That was just lasted for about two days. After I changed the pcv valve, and breather, it stopped doing that. Yesterday I drove the car on I-10 for about two hours running 80 mph. I drive the car on a daily basis.

[88hurstolds]

Chubys have different tolerences than Olds, tighter IIRC.
Ive heard stories of Chuby mechanics really screwing up Olds motors...
If theres nothing under the valve covers then my only guess is your tolerances are too tight or your lightly burning oil to where its hard to notice. The PVC was probably causing enough pressure buildup to cause some oil to burn off to where it wasnt that noticable. It probably then got caked or froze shut and then caused the oil to leak out. All speculation though...

[84Hurst/Olds]

Well I guess one of these days I will just have to tear it town and rebuild it myself so that I know what is there. Thanks for your help though.