New motor, light blue smoke

[Richard T.]

Re: New motor, light blue smoke

I had my 327 motor rebuilt and did the 20 to 30 minute break in to set the cam and a lot of smoke came out. The smoke went away but no power from the motor. I had to pull the timing cover to check the gear; it was off 12 degrees. Runs great now after I reset the gear. Your compression is good. Check your plugs after a brief run for oil. Before dropping the body run your engine a lot to make sure your are good to go. Check your exhaust tips for black deposits which means to rich. If plugs are wet with oil you probably have a valve seal problem; you can replace these without pulling the heads. I would be surprised if the rings are the problem. Good luck.

[Rich P.]

Re: New motor, light blue smoke

Jeff,

I don't want to over simplify things but with everything being either new or rebuilt it's easy to miss little things. I had a similar problem many years ago with a fresh restoration when the PCV system was not working properly.

Rich

[Jeff B.]

Re: New motor, light blue smoke

As always so much good information and differing opinions. I tend to agree that the molly rings should set almost immediately. I'm suspect of the valve seals but the engine builder used both the o-ring and an umbrella seal in combination so it's unlikely. In retrospect I would have used the PC type at least on the intake side. There is a local performance shop that can put the car on a chassis type engine dyno without the body on it, strap it down to the proper ride height and put a load on it. They also will do a leak down and check into the valve seals/guides. Basically all that can be done without a teardown. It seems like good insurance, I'm taking it there on Monday. Thanks everyone!

[Joseph K.]

Re: New motor, light blue smoke

When I rebuilt my 350/350 I had the same experience with oil burning. For the first 10 to 15 minutes the smoke was really bad. It took about 30 minutes of running it on the road before the smoke disappeared. I recommend running it a little longer before pulling the motor out. There is a very old school method of seating the rings. I only mention it since it worked well when we were kids but I cringe thinking that we did it. When the rings would not seat we but a little Bonn amy in the palm of our hand and allow the air by the carburetor to suck it in slowly. It generally worked like a charm. Not recommended in your case. Hope it clears up for you.

Joe

[Timothy B.]

Re: New motor, light blue smoke

Jeff, Let us know what the experence with the dyno is like and if they suggest any motor work. Can you tell if the smoke smells like rich gas or oil? I think slightly rich gas can have white looking smoke after it mixes with the H20 by product of combustion.

The unbrella seal may need to be used if the shop installed brass valve guides where the insert is threaded in then reamed but I am no expert in this type of work. Find out what shop did the head work and go visit them and ask before you tear anything apart.

One more thing, make sure the shop that runs the engine puts the ignition timing back to 10-12* at low idle RPM. Sometimes timing is cranked up to get a reading and left there.