Ok im having a issue. my engine in my duster is a 360 is producing alot of engine smoke. it has about 150 miles on the rebuild. it also has the keith black pistons with file to fit rings. the machine shop was saying that the engine will smoke until the rings are sealed good. i could understand a little smoke but when i drive down the road it will cause a smoke screen. any opinions. thanks

Dumb question: is there too much oil in it? Did that once- smoked out the whole block!

Slightly smarter question: does it smoke on acceleration or deceleration? At idle? Does it clear up some cruising?

Are the plugs all oil fouled? The smoke is coming out of the tail pipes, not dripping and smoking on the headers, right?

Have you done a compression test to see if the cyls are sealing up well?

And finally the smartest quesion- what color is the smoke?

no it is perfect on oil checked that. it smokes really bad on acceleration and some while idling as well.when cruising it is a faint light smoke coming from it. plugs are a little dirty but not too bad. it is coming from tailpipes. it is a blue smoke so i know it is oil burning and i havent done a compression test. i have been told it will smoke until the piston rings seal but it has about 150 miles and seems like to much smoke to me. any more help would be great i dont know alot about this stuff and im trying to learn as get some help at the same time thank you

Definitely perform a compression and leak down test on it. It is possible it could be valve stem seal related or intake to head not sealing very well, but I'd check the compression and leak down first, then go from there! Good luck and let us know what you find out.

ok i will perform them tests this weekend and let everyone know what is going on thanks

No, it should not smoke. I have KB pistons in my 360 and it never smoked. What condition are the valve guides in? also, is the intake sealing good, not sucking oil into the intake?

If all eight of the plugs look exactly the same, I'd be leaning away from the issue being with the intake manifold gasket and valve seals.

First and foremost, as mentioned, perform a leak down and compression test.

What I would be thinking about now is did the machine shop set the gap correctly for the top piston ring. Are those pistons hypereutectic? If so, they require a different gap than cast and forged pistons.

yes they are hypereutectic pistons. i recieved the car like this so im not sure what machine shop did it. also i just put a different intake on it and it still smokes so im guessing it isnt from the intake. it also smokes alot out of the oil breather when idling if that changes anything. i havent done the compression check on it yet thats will get done this weekend. i appreciate all the help and will continue to update all info i can. thanks

What kind of intake gaskets did you use? I had trouble with mine until I got some composite Felpro ones.

http://www.summitracing.com/parts/FPP-1243/

Just for the heck of it, check if the PCV valve is functioning properly. Is it open and pulling manifold vacuum?

OK i just pulled my plugs again after a little ride in it and the front 2 plugs on boths sides are covered in oil and the back 2 on both sides are a little oily but not soaked. what direction am i looking towards.

ok thank you everyone i will be doing the compression check this weekend and ill let everyone know the results and hope i get this figured out.

ok i just did a compression check and this is the results.
cylinder 1: 150
cylinder 2: 150
cylinder 3: 120
cylinder 4: 155
cylinder 5: 110
cylinder 6: 135
cylinder 7: 110
cylinder 8: 135

not very good results here. the smoke has gotten less but still smokes. im guessing rings not sealed up right?

Do the old car lot trick of dumping a handful of Bon-Ami cleanser down through the carb while it's running. I know it sounds funny but I've seen it seal rings that wouldn't seal. lol

I'm bringing this one back from the dead to ask about my 360 smoking issue.

Build is 360
KB107 pistons
340 rods
596 heads
Comp XE268
Performer Intake
Eddy AVS carb

I built the motor. Rings were properly sized and staggered.

The motor has at least 2k since the rebuild and runs super! After cruising awhile, it'll smoke heavily upon hard acceleration. Once it's "blown out", it won't smoke for a bit. Then after some more cruising, it'll smoke again on hard acceleration...etc, etc...

It also seems to use a quart of oil every few hundred miles or so and the oil seems to stay pretty dark, even after an oil change.

I've replaced the intake gasket once with no change.

I bought the heads "already done" and to be honest, never even looked at the valve seals.

Thoughts? Valve Seals? Rings?

Thanks. Good read. But there's a lot of contradictory info here. What about cam break in? What about tuning? These things have to be considered before just firing up a new motor and beating it around the block to break in the rings.

Either way, when I fired this up for the first time, I broke in the cam per Comps instructions. Then, I have to admit, the first several trips around the neighborhood were quite "spirited".

The one thing that does stand out to me though, is the honing job. Perhaps my machinist had it too rough...

Will a compression test tell me if it is indeed the ring seal? What should I expect to get for compression?

Oh, and I've checked all the plugs. They all look pretty clean. No carbon or oil build up at all...

Thanks again for the help!

Bumping this back up for discussion as it's time to tackle this issue before cruising season. Anyone have any feedback on my previous post regarding what to expect from a leakdown/compression test?