Drainage

72, 454 Bb burning tons of oil. By tons I mean 4 quarts in less then 1000 miles. She has close to 93k miles and I'm just wondering what I need to need to replace to fix the issue. Theres slight leakage from the rear main seal but it's not constant and its only a few drops over night and not every night. Any ideas?

Thanks!

MelWff

At 4 quarts per 1000 miles I would expect your spark plugs to be oil fouled, have you checked the plugs?
Have you placed the car on a lift with a running engine to confirm you have no oil leaks?
Have you done a compression test to determine if you have bad rings or just bad valve stem oil seals?

jb78L-82

Well it does not sound like you are leaking oil from the oil spots you describe. Have you looked under the car after running it to see if there is any oil coating under the car? I doubt it since 4 quarts per 1,000 miles if leaking would be all over the car and the road.

Next would be burning oil and at that rate you should be seeing pretty heavy blue smoke out the exhaust at all times or at least a coating on the rear bumper, if it is burning oil through the exhaust.

If it is burning oil, it would be either through poor ring seal on the pistons or through the valves and/or valve stem seals, most likely. If you are burning 4 qts per 1,000 miles, the motor would need a complete rebuild.

HeadsU.P.

Lets not prematurely start pulling engines. Could be stem seals & rings are fine. Could be the bottom of the intake manifold gasket. A lot of oil can be sucked in from the lifter valley. Hard to say at this point. Lots of miles on it.

Pulling / reading one sparkplug should tell a story. Put some cardboard under the engine for another story.

ajrothm

calwldlife

yup.
amazing the plugs haven't fouled.
original poster.
any work done lately?

Big2Bird

What kind/weight of oil?

Pzark

derekderek

do the intake valve seals and wiggle the valves to see how loose. exhaust don't suck oil. almost better to run no seal so they get oiled. a sign of valve seals shot. go down the road at speed and lift up on the gas. does it smoke then? the vacuum is pulling the oil in the intake guides.

Rescue Rogers

i had the same issue when I changed my heads. 1 quart about every week/ fill up. I wasnt leaving a big blue cloud every where either. It turns out I didnt have any valve seals on the heads i just bought. The PO didnt bother to replace them as he just used them on his track engine. The major oil consumption just about stopped except for the small pan leaks.

HeadsU.P.

You are forgetting that at certain timing events both valves are open, such as the intake stroke. The piston is going down creating a negative atmospheric pressure or vacuum. Both valves are slightly open. The oil vapors or mist in the valve cover area could follow the intake valve stem into the cyl or follow the exhaust stem. The oil doesn't care.

If the valvestem seal was not needed on the exhaust, you can bet it would not be added.

derekderek

During overlap there is an exhaust reversion pulse trying to fill cylinder from exhaust side. Because exhaust is under pressure. This is what headers are designed to help eliminate. Exhaust valve guides are always looser than intakes. Cuz they are not as well oiled. A lot of people do not run exhaust stem seals at all.

Drainage

I didn't expect to get this much feedback so thank you all. Firstly theres a slight coating of oil on some hoses beneath the engine. It really on leaks oil that I can visibly see on the drip pan and that's just a couple drops. I'm using 10-40 and my oil pressure is constantly around 70 unless it starts running low. Theres a slight bit of blue exhaust when warming it up but I cant tell when driving. There appears to be no film on the bumper. I had the oil changed, distributor and plugs and wires updated about 800 miles ago. It doesn't have a skip yet but it had in the past and it was always the hardest plug to get out.

Pzark

derekderek

that sounds like rings. with bad valve seals you will see a nice puff when lifting up at highway speed. another possibility is PCV. unhook it and cap off the vacuum source. and see if it is any better. ALSO look at the amount of blowby when PCV is not hooked up. high blowby doesn't necessarily mean rings are using oil, but the blowby can be pushing valve splash oil into the intake. high perf boats don't use PCV. some use a puke can the blowby is vented through to catch the oil instead of blowing it all over the engine compartment. orig engine, never rebuilt? tired engine will be a combo of everything, so valve seals will still reduce consumption enough to justify the afternoon and 50 bucks in seals and lever style ring compressor. straight 40 or 50 oil will help a little too.

scrappy76

That is a lot of oil. I would think if you were burning that much, you would be fouling plugs and leaving a smoke screen whenever you drove it. If so, its going to be valve seals or oil rings. Also as already said, check your plugs and you pvc valve. If your rear seal is shot, your not going to leave huge puddles when off and parked, but it will be dripping pretty good when running and driving look at tranny and underside of it for oil all over the place too.

jackson

gkull

You are burning only one quart per tank of gas. The first thing to do is a leakdown test. Forget compression testing it's something that the uniformed use

well any recently my vette had visible blue smoke on start up and under acceleration. Leakdown testing showed that my rings and valves were in perfect health. My guides and pc seals needed replacing at 20,000 miles or less.

90k miles probably has ring ware and worn cylinders. If you are up in the teens on leakdown testing percentage plan on boring the block. 454 motors had marginal balancing, heavy parts, and the long stroke. I have rebuilt ones with less miles than yours.

Big2Bird

If the car does not look like a destroyer laying a smoke screen, look at the valve cover gaskets. A friend was using oil like you. When driving, the oil built up at the back of the heads, and leaked out while driving. When stopped, it just left a few drops. Took him awhile to figure it out.

jb78L-82

I can't wait to hear the outcome of this one. I would be shocked if it is an intake gasket sucking oil...Doubtful....or just about any of the other theories about oil combustion...the plugs would be so fouled the engine would barely run if at all or would billow blue smoke.. Any engine consuming 4 qts of oil every 1,000 miles is either going to show external leaks that are massive OR smoke like a chimney from internal combustion of the oil OR oil coverage externally all around the engine and under the car. Something is very weird here..........