dpfarrell

That could be but I am pretty sure that I replaced the valve seals correctly. Do you think that it could be the oil rings let oil get by them when its cold, and then when it they warm up and expand they stop letting oil by them?

Thanks for all the input.
Greatly appreciated.

DansYellow66

Beats me - but interestingly I was watching an episode of Bitching Rides the other day and they had a roadster blowing oil smoke pretty good and tried replacing valve oil seals without luck. They tore down the motor and found one cylinder where the expander/spacer for the oil ring was overlapped at the ends rather than butted up. That fixed the issue. But before they fixed it, it just kept blowing smoke - it didn't clear up as the motor warmed up. Your issue just seems to fit with some sort of a valve problem. I would bet on GTOguy's response or something similar.

Frankie the Fink

If you hold your hand behind the exhaust when the engine is smoking is it a blue smoke which leaves a greasy residue on your palm or a moist, watery residue from whitish smoke. I'm not convinced the symptoms are correct yet.

The things that happen as an engine warms up are the choke opening, exhaust PS manifold heat riser opens (if there is one), engine clearances expand and idle drops.

If there is oil sitting on the heads from the engine sitting it'll get sucked down into the cylinders.....could be a crappy valve seal repair job. I wouldn't rule out a head gasket issue. It all depends on identifying what's coming out the *** end of the car. 99% certain leaves 1% in doubt..

65tripleblack

Is it BOTH banks that are smoking?

Usually bad valve seals cause smoke immediately on startup.................not 1 full minute after. Pooled oil gets sucked into the chambers, smokes until it's burned off. This fact leaves me wondering if it's not something else, like differential expansion between aluminum heads and iron block causing leakage until both reach same temperature and equalize.

Try running the engine until the smoke starts, then shut it off, pull plugs, do leakdown again and listen for air at tailpipe (leaky exhaust valve), carburetor (leaky intake valve), and oil filler (leaky rings and/or head gasket) for each cylinder.

Powershift

IF it is oil and not unburned gas, and the carb is not the issue, then this is about the only thing left. Not certain how best to solve it.........perhaps doing what is suggested above and also pulling the intake manifold to check for clues in the old gaskets and in the intake runners. Could be a hairline crack somewhere that opens ups when cool and closes off after engine is up to temperature.

Since it is intermittent and not continuous, I would probably live with it until things get worse..........if they ever do.

Larry

GTOguy

Doing a leakdown test and listening to where the blowby is coming out may help. You'll need to do all cylinders. I'm convinced you are using oil by your description of the smoke and your apparent knowledge! My gut tells me it's valve guides/seals, though. A bad oil control ring would burn oil all the time.

6T7L71CPE

From my personal experience attempting to control oil burning in my BBC,
if the guides are bad enough, new seals won't fix the problem. Apparently the white teflon seals don't have a large range of flexibility. Mine has the Viton with teflon seal.

68hemi

It has been my experience that if it is guides or seals It will smoke on start up then clear up. If you let it idle for a while and then hit the accelerator with no load on the engine it will puff smoke again. Also if you are cruising at a steady speed for a while and then accelerate hard it will smoke again. What is happening is that the oil slipping by is building up with a small amount being burned at cruise that you don't see. When you hit it harder it burns the build up quicker so you can see it.

Frankie the Fink

I think it will smoke on deceleration when engine vacuum spikes. If it smokes under load, consistently, it's rings most often.

GTOguy

You think right. High manifold vacuum (deceleration) will suck oil past the valve guides. Easy to spot when following a car coasting down a grade or exiting the freeway. I think the OP has worn guides/seals, and that's what I would check before the next step, which is pulling the engine down.

Robert61

What kind of seals did you put on? Those white Teflon seals are worthless and will definitely cause problems.

Frankie the Fink

Yeah -- can't reconcile the 1 minute lapse before the smoke on a cold start though.

DansYellow66

I still wonder if that couldn't be due to most of the oil leaking past the guides is on the exhaust valves. If the valve seats are in good shape, except for the open valve or two the oil will sit on top the valve and blow into the exhaust manifold upon starting. Give the manifold a minute or so to get blistering hot and the oil starts to burn off.

Seems I remember that BBs are hard on exhaust valve seals and guides.

Yes? No?

hope2

Throw something out here; Cylinder head oil drain hole(s) restricted, causing oil to puddle and drain into cylinder(s) normally via valve seal, possibly crack.

hope2

Far fetch; intake manifold sucking oil out of valley on startup.

Frankie the Fink

Except its not on startup

cv67

w/gto guy a refresh on the heads if seals doesnt get it should set you right

dpfarrell

Thanks for all of the discussion. Yes it does blow smoke out of both banks.

If I can eliminate the issue is with the rings then I will not have to pull the engine.If it is an issue with the heads,gaskets,or intake, that will make my job easier.
As I recall from doing a leak down, the noise is coming from the PVC or air breather holes in the valve covers.
I will run some of the tests discussed earlier and get back to you.
Again thanks for all the help.

survivor66

Hope it's not bad oil rings as I first suggested. They expand as engine warms like everything else, and could be gunked up and worn, preventing them from sealing properly when cold. That would result in leak down sounds through the crankcase.

Robert61

What seals did you use?