mpro71vette

I have side pipes and on the left side I have black stuff coming out. Is this oil or soot? It doesn't feel like oil? It is a 1971 and has a new engine, 383.

mikem350

Yes its soot, maybe oil vapor, and water vapor. Should go away when everything heats up!

mpro71vette

What a relief, Thanks!

bj1k

It's normal for a new engine to show those symptoms while it is being broke in . It will even go through more oil while breaking in. Should start going away after 500 miles . If it doesn't then it is time to be concerned.

mpro71vette

OH Great, I already went 500 miles, what does that mean now?

bj1k

I said start going away . Give it some time and clean out the exhaust to see if it is fresh . 500 miles is only the initial break-in . Might take a couple thousand . How did you break in the first 500 miles . Hard or easy ? If you raced it right away then there is nothing that you can do to undo the damage. How many miles are on the new engine ? Was it new or rebuilt ? If rebuilt was it a reputable company ? It's really hard to say without knowing the history. Might be as simple as the carb burning too rich, who knows ?

mpro71vette

AH Ok, its a rebuilt engine from blueprint engines. I broke it in easy. It is only happening on my left side. I have about a thousand miles on her.

bj1k

OK then if it is just the left side it wouldn't be carb. Most likely going to be ( if it doesn't stop ) something wasn't done right on the left bank. Could have just torn the valve seals on the left head when installing them , happens sometimes. I had an engine that supposedly was rebuilt by a professional builder and it was getting some oil out of the right side exhaust and when I removed the head you could see tears in some of the valve seals. One was torn in half . New seals fixed it and that is not a big job. Hopefully it is not a problem with the rings or bore but not likely.

mpro71vette

Thanks, I'll bring it to the corvette shop and have them check it out.

rick1025

If it does it on acceleration it is probably rings that have not seated in. If on deceleration,valve seals.

bj1k

As a general rule that is true but if there is no smoke in the rare cases like my engine which had no noticeable smoke but a lot of raw oil in the exhaust tip and my wife said that she always smelled a strong oil smell. It filed the plugs so fast that it didn't have time to burn at a noticeable rate. I replaced the valve seals with the stock seals and also added the umbrella seals . That took care of the problem.

Antz81

I have the same problem with mine. Both side did it when I first got it, but after sorting out a few problems it's only the left side now. Goes away once the engine has warmed up. Always figured it was just soot from the exhaust mixed with some moisture.
Should I be looking more into this?

mpro71vette

Mine seems like its just soot, I only notice it in the garage. I do not smell any oil.

Kevin68

If it is water and soot that doesn't go away when it heats up, I would be thinking head gasket. Might try to re-torque the head on that side.