rebuilt motor still smoking after 300 miles

[firebird_1995]

An engine I re-ringed is still burning oil after 300 miles. I've heard they can burn oil up to 1000 miles but I've never had still (noticeably) burning oil after a few miles. This one has me stumpped. I honed the cylinders and the heads only had 30k miles and 5 years on them after being reworked. Anyone ever had experience like this?

[RamAir95TA]

You say "still burning" as if it's okay for a new engine to burn oil...it is NOT.

We did not build the motor for you so we can only suggest possible causes for burning oil (assuming you're getting blue smoke out of the exhaust).

What kind of oil did you use for break-in? Valve seals replaced? Check your ring gap PROPERLY? Thread sealant on the rocker studs?

[firebird_1995]

Ring gap was checked and good. Rocker arm studs were thread sealed. Valve stem seals were replaced when the heads were rebuilt 5 years / 30k miles ago. 25 miles of 5w30. 200 miles of 20w50. Currently running sae 30. Im going to pull the plugs and see which cylinder it's coming from and do a leakdown test. I guess the valve stem seals could be dry rotted from sitting. The heads sat for 4 years prior to the re-ring. I appreciate all input.

[Low N Slow]

How did you seat the rings? Babying a fresh build without putting a load on it can cause the rings not to seat and could possibly cause oil burning.

[RamAir95TA]

Ring gap was checked and good. Rocker arm studs were thread sealed. Valve stem seals were replaced when the heads were rebuilt 5 years / 30k miles ago. 25 miles of 5w30. 200 miles of 20w50. Currently running sae 30. Im going to pull the plugs and see which cylinder it's coming from and do a leakdown test. I guess the valve stem seals could be dry rotted from sitting. The heads sat for 4 years prior to the re-ring. I appreciate all input.

I'd check on those valve seals. 4 years is a LONG time for something as important as valve seals to be sitting dry. Honestly I'm not sure why you didn't replace them prior to putting them on. Whether that's your problem or not I'd replace them anyway.

[firebird_1995]

honestly, im not sure why i didnt replace them either. i will plan on replacing them during the leakdown test. thanks for the input. i promise to never rebuild an engine again.

[95ImpySS]

Heh, Rebuilding engines are fine. Must do extensive measuring and prep work. IMO cleaning and measuring, boring, honing etc should be left to the machine shop. Unless you have the tools and guides to perform the tasks. There is a possibility that the bores could be worn out in different places. Cracked piston, internal vacuum leak, or excessive oil in the PCV system.

Did you check ring gap at the top, middle and bottom of each cyl?

What was your gap?

Is the car running properly? If your running rich, you can and will wash out fresh rings very quickly.

Your sig says you have home ported heads. Did you happen to break into the rocker stud holes on the intake ports? What sealant did you use on the rocker studs?

[firebird_1995]

I believe the question asked in my op wasnt worded very well. Im not at all an "expert" on rebuilding engines but I have done it several times over the years with good results. This particular build (stock lt1, not the one in my sig) has been the exception. The reason it was burning oil turned out to be the intake manifold gasket. Runs like a dream now. Thanks for the reply.

Btw, i never ment for the title to read "help!" It does that for some reason when I post from the android app.

[95ImpySS]

Glad you got it going right!!!