my motor (on my sig) is pissing me off. we just finished rebuilding it, but there's smoke coming out of the exhaust...sometimes a little, sometimes, a lot. at first, i thought the heads might have been cracked, but there would be oil/coolant in the exhaust.

the motor has about 1.5 miles on it, so i KNOW that it hasnt been been broken in yet, but still...is it common for a new motor to have smoke in the exhaust until it has more miles on it???
i'm well aware that seals have to be set in, but would that cause smoke? oh, the smoke is blue-ish.


can anyone shed light on this?


anyone experience something like this?

thanks,

shokor

 

valve seals above the valve retainer shim!!!!!

if you used your old ones then they might be worn or ripped when you took them off, if ou went to autozone and got a cheap set....maybe they are too tight against the valve and travel with it as it moves up and down, thus ..possible letting oil get in ...thus burning in the exhaust!!!!!


other than that...rings???


good luck

 

What color smoke?

Your fuel curve could be off, causing unburned fuel to get into your exhaust, causing smoke.

 

he said it was blue, so i thought it was oil!!!

anybody else?

 

all the seals and gaskets were bought from GM. i spent about $450 on seals and gaskets.

--shokor--

 

it's blue...unburned fuel is black smoke, i believe.

 

How long did you run it?Maybe assembly lube burning off.It is normal for a new engine to burn SOME oil.Run it fairly hard to seat the rings,if it still does it bad I would guess valve seals.Either that or possibly an oil ring installed upside down.

 

It's the valve seals, give it some time to break in. I just did my 70 Chevelle, and it did the same thing on the start up and about first 1000 miles of driving. Once i got to do a oil change the smoke started to go away.

Vinny

 

thanks A LOT, guys!! this puts my mind at ease for a while...unless it turns out to be something more than just a seal setting in. but, i'll take your advice, and put some good miles on it, hopefully, that'll knock some sense into it.

--shokor--

 

Valve seals don't "break in". That's like saying you have to break in your header gaskets The smoke is most likely your rings. It takes a few miles to seat the rings. I ran my motor at reasonable load and rpm, varying rpm/load a lot the first 200 miles. After that, the smoke was getting better and better as the rings were seating. I ran a couple of times WOT NA, then sprayed it with a 50, then a 100 shot of nitrous a few times. Now with less than 500 miles on the motor, it's almost completely clean.

Now that I have my suspension almost done, I'm doing to step up to the 150 pills and hope for traction

Give it a couple 100 miles before you hit WOT (but don't baby it), then report back how much it's smoking.

 

I would not be worried yet. The rings are not seated yet. Depending on the shape of old the motor when it was removed (blown up, smoking, blown head gasket, using oil, etc, ) there could be some of that stuff still in the exhaust and needing to burn out.

NightTarin66

 

that's what i was thinking, but what doesnt add up is why is doesnt smoke the same amount all the time...sometimes there's very little smoke, and other times, there's A LOT of smoke.

--shokor--

 

Since it is a new motor is the oil pressue good or stay good as it warms up?

Is it consuming oil or water? have the levels of each changed?

I would check the plugs and see if any look diff. from the others. Look for 1 rusty colored or cleaner plug or maybe even 2 side by side (maybe head gasket) or one covered in crusty oil residue (leaky guide seals, intake gasket sucking oil, etc.)

It might not hurt to do a compression check as you pull the plugs.

Hope this helps.

I haven't seen the amount of smoke or the changes in the amount of smoke but hopefully there are some ideas for ya here.

GOOD LUCK.

NightTrain66

 

YES!!! alright, we found out what the problem was. the stock gaskets, which i bought from GM, were inadequate for the ported heads. the gaskets were allowing oil leak into the intake, hence the smoke.

well, this is a future reference for anyone building a motor with ported heads and trying to use stock gaskets.

i appreciate the help all you guys gave me. thanks a lot.


--shokor--

 

ugh!! ok, the car is STILL smoking...we doubled the intake gaskets and siliconed the hell out of em. it's still smoking...now, i'm getting scared.

maybe the heads are warped, or the port job wasnt done right...or the valve seals arent good...or maybe it's the valve guides.

but, i bought some fel-pro intake gaskets...hopefully, the oil is leaking into the intake due to a bad intake seal...if not, then i'm screwed...because we'll have to take the motor out and take the heads apart.

any idea on how much valve guides and valve seals cost?

--shokor--