Put together a 396 for a buddy last winter and fired it last spring and now he commented that it smokes. It runs great and pulls hard and he says it is the best motor hes ever had in the car but it does smoke some. Here is the weird thing it doesnt do it all the time. Sometimes at idle it will sometimes it wont... after running down the highway sometimes it will.. sometimes it wont. but when it does its not just little wisps of smoke it is a cloud. And whenever i have seen it, the smoke is real faint blue but mostly white. He had the carb all messed up and I reset carb but it still smokes a little. Did a leakdown test and got anywhere from 44%-6% leakage, but we are not sure we were able to get the fitting screwed in tight due to clearance problems so i dont want to rely on these numbers. Most of the plugs looked alright except for the front 1 or 2 on ea side were completely black, others were good. The one that looked the worst is the one cylinder we got 6% leakage on. The block was fresh bored/honed, sealed power rings and keith black pistons, heads were gone through with new guides and seals and surfaced.
What am i missing or what do i need to look for. Any body else have this problem. the thing only has maybe 1500-1700 miles. I would think the rings should be seated by now.
What about oil? Has anyone had trouble with rings seating on CAstrol oil? I remember someone telling me once that Chevy had trouble in the early 80's??? witht their pickups smoking and it was a GM bulletin that said to switch to Trop ARtic oil and the smoking would stop then you could switch to whatever oil you want. I assumed this dealt with rings seating better with Trop ARtic.

I guess if we have to we can tear it down and go through it but would be nice to fix it now if we can.

I don't have any help for you, but I'll be interested to see what others have to say. A buddy of mine has had similar problems with his 454.

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Chris Avery
'69 Nova, 355, 9.3:1, Keith Black 12 cc D-cup hypereutectic pistons, 180 cc Dart Iron Eagles w/64 cc chambers, Comp XE-262, Crane Energizer 1.6 ratio roller rockers, Performer RPM, Holley 650 DP, TH350 w/B&M shift kit, B&M 2400 RPM Torkmaster converter, 4.10 10-bolt posi. Best 1/4: 13.098@103.41, 1.949 60'

anybody???

Is the car using oil or antifreeze?
Anything hitting the driveway?
Maybe head gasket, or rings.
If it's using antifreeze I would take the heads off and check it out.
That's all I've got...

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'86 firebird pro street
452 bbc 13.5-1,781 heads,
roller cam,48" Moser 12 bolt,4.56 spool,400t w/brake

Does the smoke have a sweet smell to it? The way you describe it,it seems like water getting into the cylinders. Put some air in the radiator for a pressure/leak test and see if it holds or goes down.

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1969 SS 396 Camaro/Th 400/355s.(454 now)
Not a Chevelle but the BBC guys are here!

Our 454 was doing that occasionaly smoking it runs good and pulls good but it was smoking we rebuilt the carb adjusted timing and it quit smokign maybe timing?? or water is getting in the cylinder. but i wouldnt expect that on a rebuilt

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1969 Chevelle 454
Factory a/c
4speed
2.53 non posi 10 bolt =(

Visit my site:
"http://24.145.153.235/car.html"

I sure wouldn't tear it down, if it was a hard part it it would smoke at a given criteria every time, sounds like wiring or pos. carb. related..

I would dbl check the pcv to intake. Sometimes while decelerating and vacuum is high and depending on valve covers the pcv can pick up oil straight to the intake. I had this problem once. The rocker lined up with the valve cover vent opening and shot oil directly into the pcv and to the intake or base of the carb. Smoked lots, but not always. That was the funny thing. Changed valve covers which relocated the pcv and added a second breather to the underside of the air filter and the problem was gone. Just an opinion.
Good Luck

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Bu By U
81 408 SBC Malibu Wagon
700R4
3.73 Posi

Thanks for the input guys.

The exhaust doesnt have a sweet smell to it so i dont suspect water. More gassy than anything with a hint of blue. I have come to the conclusion that it must be rings. I readjusted carb and checked timing (16 initial 36 total)and seemed to help a little but still puffs a little bit. The PCV is a good thing to keep in mind but right now he's just got breathers on it. I cant help but think the rings should be seated now but i guess there is a chance they are not. The smoking isnt as bad as it was a month ago so maybe it just needs a little more time. Never had this problem before, never had a fresh motor smoke at all and i use the same shop and same rings so i dont think its a problem with bore finish. Still wonder about oil. I have never used Castrol.. maybe its slowing down the seating process a little.

Thanks again and if you have anything more to add... i appreciate it.

How about the ring gaps, did you leave the appropriate gap (although this would lead to blowby out of the breathers). You really should try the pcv valve for a street engine before teardown, it will eliminate some pressure in the crankcase that could cause oil consumption past the rings. The rings should be seated (if cast iron or moly) by now. Are you sure you didn't install a ring upside down. That happens sometimes. What kind of valve stem seals did you use PC seems to be the best.
Just my two cents

Ring gaps are correct except for opening up the top ring per KB specs. Maybe i opening it a little far though. Not a lot of blowby out the breathers though.
Pretty sure none of the rings are in wrong i triple check that, once when i put them on, once when i get done with them all, and one last time before they go in the block.... i am human though.

Cant remember on valve seals.... whatever the shop put on them... I think umbrellas but not sure i would have to look at receipt again.

Here is the Service Tips Page at Hastings (http://www.hastingsinc.com/service_tips.htm). A lot of info on burning oil problems. My 355 started smoking a lot. It turned out the thrust bearing failed allowing way too much crank end play (this was due to the torque converter pushing the crank forward). This caused the rings to spin much faster than they should have and wore them out. Check this crank end play (http://www.hastingsinc.com/Service%20Tips/factors_influencing_oil_control.htm). The info is at the bottom of the page.

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Pat Kelley
66 El Camino, daily driver
67 El Camino, STRIP/street (12.08, 113mph, 7.500@92.14 1/8 mile) 355 powered
Pat's Page (Dynamic Compression Ratio Calculator, car specs, Spark plug reading info) (http://cochise.uia.net/pkelley2/)

[This message has been edited by Pat Kelley (edited 11-11-2002).]