adam

My car burns oil at a rough rate of 1qt a 1000-2000 miles (very rough estimate.)

I know one source is oil leakage down the valve stems. Another is leaking
past the rings. Another is sucking oil from the lifter valley in the intake.

I'm curious as to which leaks more, valve stems or past the rings?
Is it worth the time/effort to put on new valve stem seals given a motor
of unknown age (since rebuild?)

TedH

I'm assuming that with my low-mileage engine (20K) with new heads that my problem is intake gaskets that I failed to properly dope up with sealant. I installed them dry and suspect I am now paying for that. I will be installing Fel-Pro 1204 gaskets with just enough gasket 'glue' on both sides to ensure a good seal. Also going with a set of 3/8" head 12-point ARP intake bolts for good measure. Will also be laying a small bead of sealant at front and rear of the intake instead of using the chincy rubber gaskets that rip and fall apart after 4-5k miles.

vette_c5c6

So whitch is it 1-qt@1,000 or 1-qt@2,000 I would not worry if its 1-qt@2,000

WESCH

Hi

This oil consumption is not unnormal for a older engine.
As long as it doesn't produce blue exhaust fumes, nothing to worry about.
Valve stem seals are easy to check.
Pull the ignitor plugs after an overnight in the garage, if they have streaks of fresh oil on them, the seal stem seals are bad.
For the piston rings, you could do a compression test. If all cylinders show +- 20 % same pressure rise, the rings should be OK.
Sometimes, using a thicker oil can reduce the consumption.
I also heard that switching to synthetic oil ( Mobil 1 ) will reduce the consumption , even that this is a thinner oil ??

My 68 BB got overhauled ( new guts + .030 oversize ) about 8.000 Miles ago and is also using this amount of oil. I did replace the cracked valve stem seals and this reduced the consumption by some, still high.
Don't worry too much , at least you don't need to recycle the oil so much. :lol:

Good luck. Gunther

UKPaul

Another possibility (& I don't know if it applies so much to the SBC) is excessive crankcase pressure. This can be caused by worn rings/bores (which will burn oil anyway) or a problem with the breather system. If the PCV system is allowing oil vapour/droplets to escape then it'll show all the symtoms of a worn engine/seals.
:cheers:

mayberg

When changing spark plug wires I noticed that my valve cover bolts were loose. I don't yet have enough miles (too hot in OK) to see if that has impacted my oil consumption.

adam

THanks Guys;

I have a set of heads with some good valve seals and was wondering if
its worth the time to swap these seals for the ones on the car.

I'll have to monitor my oil consumption more closely.
UKPaul, thanks for the tip - I'll check that. I already have checked
my valve covers and replaced one broken gasket.

71coupe

Wesch - I've read the switching to a synthetic oil will lessen the chance of pre-ignition/detonation on a oil burning engine.

I think the root cause of burning oil is not changing it enough (dino or syn)
Acids form in oil over time which will corode almost anything (rings, valve stems, dipsticks, oil fill caps, etc). This starts a chain of events that causes the begining of the end. :sad:

Along with the acids that form from fuel and moisture, you also have airborne particles constantly getting in the oil. I think it's cheap insurance to change the oil often - dino or syn.

isosceles

Buy new ones(orings) and get the umbrella seals too. For the Felpro umbrella seals and the orings, I paid less than $20 at Autozone.
It's not hard to do, even easier if you have a compressor (I don't), and you will no longer get that annoying blue flume at startup.

fst_c3

I thought it was my heads causing the smokeing problems, they were in bad shape when we pulled them. I got new GM high performance heads and a cam,timeing chain, and put it together.Still smoked just as bad. Took it all apart and had a broken piston. But she is all better now.