underhood smoke & exhaust question(s)

[67CudaBob]

I have had some time recently to mess around under with my car. I am pretty much a rookie under the hood, but willing to be a decent student.

273 with recent LD4B and Edelbrock 1406. Internals of motor unknown, other than rebuilt 20 years ago with not much detail on paperwork other than going 30 over on cylinders. Previous owner was an older lady, so I doubt anything performance was installed internally. (I had the intake and carb installed this spring)

I noticed 2 things after I set my timing today. (these may have been there before, I really am not sure)

1. When the car is cold, and I rev the engine - there is a poof of oil smoke that come up from the passenger side of the carb. I cannot determine if it is the valve cover or from the intake or something else. As soon as the car warms up, I cannot reproduce the smoke. (makes me think gasket swelling and closing a gap maybe?).

2. As car kept running, now warm, I noticed out my dual exhaust that there was grey smoke/exhaust coming heavy and steady from the passenger tailpipe, but very little smoke/exhaust from the driver side tailpipe.

Are these two things likely related or am I dealing with 2 different issues?

And - would a timing adjustment have brought either of these things on? Timing was 5* ad idle (vac plugged), and roughly 24* a higher rpm (no tach available). Now it is set at 15* idle, and it seems to top out around 28* at higher rpm.

 

[TrailBeast]

It would probably help if you could pinpoint that puff of whatever.
Valve cover vent?
Carb base?
Other?

Changing the timing may have brought on a scenario where it now lean pops back under cold acceleration or something, but if it's within a range it should be that wouldn't cause what you describe.

More likely a puff from the block because of some problem on that passenger side where you see the smoke coming from, and grey or black smoke is too much fuel and blue smoke is oil burning.

Plugs tight? or have you pulled them and seen what they look like?
It could puff from a loose one when cold.

 

[67CudaBob]

Will try it again here within the hour. Puff is definitely on the topside though, halfway down the head, not underside by plugs. I will take a pic of location and try to post. There is some discoloration on the newly painted manifold - maybe that is an indicator . I will also pay more attention to the color of the smoke as well and update.

 

[67CudaBob]

View attachment engine smoke.jpg

Had engine cool and started over. Smoke under hood is definitely blue and smells of oil. The location (I don't speak tech, so bare with me) appears to roll out from under the head (where the crossover is - but I believe they closed off the crossover on the intake when they installed it). Basically the exact middle of the picture posted.

Out the exhaust, passenger side has definite blue hue where the driver side is just plain gray exhaust.

thinking an intake gasket leak at the sealed off crossover and some oil getting in the exhaust on that side? Sound right in theory?

 

[TrailBeast]

View attachment 1714853679

Had engine cool and started over. Smoke under hood is definitely blue and smells of oil. The location (I don't speak tech, so bare with me) appears to roll out from under the head (where the crossover is - but I believe they closed off the crossover on the intake when they installed it). Basically the exact middle of the picture posted.

Out the exhaust, passenger side has definite blue hue where the driver side is just plain gray exhaust.

thinking an intake gasket leak at the sealed off crossover and some oil getting in the exhaust on that side? Sound right in theory?

The oil in the exhaust is probably not coming from that crossover leaking (possible I guess, but doubtful)
That oil on the intake by the bolt is oil coming up through the bolt threads then between the washer and intake.
Most people talk about using sealant on the bolt threads but I found that sealing the bolt threads and around the bottom of the head where the shank and head come together really solves it.
You will be cleaning up a little sealer around the washer to intake afterwards, but they don't ever seep again.

I'd be pulling plugs to see what they look like on that side of the engine. (black, oily, whatever)
If they all looked good and close to the same, then I would suspect maybe the crossover but usually they only smoke from there after running for a few. (gets hotter'n hell there when running) and any oil seepage is burned off within a couple of min after starting the engine. (Not like you said "Right when you start it")

Also I had a smallblock that had leaking valve covers once that after a min or two of running you would have swore it was burning a ton of oil. (big cloud of blue smoke)
It was because the oil from the covers was seeping between the block and the exhaust manifold while sitting and then burning and blowing out the tailpipe when the manifold got hot enough.

It freaked the guy out that wanted to buy it, but I told him if I was wrong I would give him his money back.
He put new V cover gaskets on it and it completely cleared up after 10 min of running.
That happens pretty easy on those engines that have metal to metal manifolds with no gasket.

 

[AJ/FormS]

I'd agree with;Burned through gasket at the EGR passage, and whatever TB says.

 

[67CudaBob]

View attachment pass side plugs.jpg

from right to left is front to back of motor. Note the black oil/sludge on the bodies of the 3 left most plugs. Outside of the oil on the bodies above the threads, they all look similar in condition compared to each other, and compared to the driver side ones I pulled (none of the driver side ones had oil above the threads, but all were tightened what I would consider normal for a plug.

Odd thing about the 4 of these on the pass side is that they were all not more than finger tight. The driver side ones took a little oomph to break loose.

Would an under torqued plug cause oil to leak out onto the body of the plug?

I am thinking tomorrow I will replace all the plugs - clean up around the plug holes - clean up around the intake crossover - seal the intake bolts and see if I can further narrow down what I am dealing with.

I really appreciate the help all.

 

[krazykuda]

Maybe the last person to put in the plugs forgot to tighten the pass side ones, just hand tight....

 

[TrailBeast]

View attachment 1714853695

from right to left is front to back of motor. Note the black oil/sludge on the bodies of the 3 left most plugs. Outside of the oil on the bodies above the threads, they all look similar in condition compared to each other, and compared to the driver side ones I pulled (none of the driver side ones had oil above the threads, but all were tightened what I would consider normal for a plug.

Odd thing about the 4 of these on the pass side is that they were all not more than finger tight. The driver side ones took a little oomph to break loose.

Would an under torqued plug cause oil to leak out onto the body of the plug? Yep.
Do your valve covers leak down onto them also, or just the plugs loose?

I am thinking tomorrow I will replace all the plugs - clean up around the plug holes - clean up around the intake crossover - seal the intake bolts and see if I can further narrow down what I am dealing with.

Be careful when cleaning around the plug holes so you don't knock crap into the cylinders.
I like to spray brake clean, or some sort of solvent around the plugs while they are in and then blow off the junk.
This way nothing goes in the cylinder.

I really appreciate the help all.

I have a good tip for cleaning up that kind of stuff for you.
Using an old carpet cleaner with a 1/2 or so hose adapted to the suction hose works really well for sucking up the soapy stuff from cleaning in area's like those so the cleaning solution and grease doesn't go all over the rest of the motor.
They always break somehow, but never usually the vacuum part and holding tank.
I even use it to suck up low volatility solvents like engine degreaser.

I don't think I would be very confident about sucking up anything more volatile than that with it though due to possible explosion caused by the sparks from the brushes in the electric motor.
Deisel, Kerosene, degreaser, yes.

Gas, alcohol, paint thinner, lacquer thinner, no way.