Rebuilt engine smokin' up a storm

Raindem

Veteran Member
Jun 3, 2012
173
Sonoita, AZ
I'll be taking off the intake in a bit. Just wanted to post the compression numbers on the re-test. Squirted some 10w40 into the cylinder for the wet test.

Cyl Dry/Wet
#1 120/130
#2 125/135
#3 130/140
#4 130/140
#5 125/135
#6 130/150
#7 135/145
#8 135/145

So is a 10 psi bump normal for a late 70's SBC? If yes, then I'll continue tearing into the top end. If not then we're back to rings.

Correction - I forgot to block open the throttle on the above test. Re-did the test (dry only) and values went up 5-15 PSI. Dry compression is now 135-155 for all cylinders.
 
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Raindem

Veteran Member
Jun 3, 2012
173
Sonoita, AZ
Just finished pulling the intake and the gasket looks good. No visible breaks or evidence of oil being pulled in through the intake runners. I tried to look into the top of the valves but I couldn't see them very well. There is a little moisture in some but I can't tell if it's oil or gas from all the cranking.

I can tell this thing is going to fight me to very end. Tomorrow I'll start on the heads.

On second thought, I think I'll just pull the engine at this point.
 
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Raindem

Veteran Member
Jun 3, 2012
173
Sonoita, AZ
I haven't looked at the exhaust runners yet. There's a lot of black soot at the tailpipe but I assumed that was from running rich.

I hear ya about just pulling the heads, but I work by myself and have trouble lifting heavy objects out of the engine bay. In fact I had to use the hoist to get the intake off. So in the end it'll save my back doing it this way. Besides, I also have a leaking RMS that I can take care of while it's out.
 

BUSHY 409

Veteran Member
Nov 25, 2006
349
Acworth GA.
I going to say rings do to any # of things crome rings , not honed right , wronge ring set , did you clean the ring leads ,up side down rings ,did you scuff the bores with 400 grit >> it is not going to fix itself i would poll it and tare it down before you hurt something like a braking ring wicken the bore up wrong thickness rings turning sideways in ring leads OR JUST THINK OF ALL THEM LITTLE SPRINGEY THINKS FROM THE SEALS GETTING ALL GROUND UP & MAKING 1000'S OF PASSIS THRO THE MILL IN THE OIL ...
 

Raindem

Veteran Member
Jun 3, 2012
173
Sonoita, AZ
BUSHY 409 said:
I going to say rings do to any # of things crome rings , not honed right , wronge ring set , did you clean the ring leads ,up side down rings ,did you scuff the bores with 400 grit >> it is not going to fix itself i would poll it and tare it down before you hurt something like a braking ring wicken the bore up wrong thickness rings turning sideways in ring leads OR JUST THINK OF ALL THEM LITTLE SPRINGEY THINKS FROM THE SEALS GETTING ALL GROUND UP & MAKING 1000'S OF PASSIS THRO THE MILL IN THE OIL ...

I'm still leaning towards valve guides as the most direct cause of the smoking. There's certainly something going on with the rings also, to account for the low compression, but I don't know if they're contributing to the smoke. In any case, yes, it's going to get torn down and rebuilt.
 

Raindem

Veteran Member
Jun 3, 2012
173
Sonoita, AZ
global warmer said:
take the intake manifold off and check your gaskets. I believe you are pulling oil into the cylinders at that gasket

I already did that. Gasket looked good and no evidence of oil in the runners. I really would have liked it to be the intake but my car is quickly falling into the "worst case scenario" category.
 




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