Motor only has about 700 miles on it and runs strong. When I rev the motor high I first get a puff of black smoke which I know that its running rich. The thing is after I let off the throttle theres a puff of whiteish greyish smoke which has me stumped. The car dosent smoke any other time unless im at WOT. What could be the reason for the whiteish greyish puff after im off the throttle ?

 

What head gaskets did you use? Is the motor bored over? Did you follow proper torquing specs for the heads?

 

Dont know about tht gaskets and specs becuase I had it built by someone. The over bore was i believe .030

 

rings have not seated yet.......need to put more miles on it

 

Is there any possiblity a leaking intake gasket would cause this ?

 

While anything is possible, i have to agree with 1fastz. I've always heard to let a motor break in for 1500 miles before you run it hard, but that really depends on the rings you used, as moly rings don't need as much time to seal.

 

i've heard about rings on seating as well, a friend of mine babied his maro for 1500 miles before taking it to the track

 

I don't think so, but you can always take some carb cleaner and spray around the intake ( with the engine running) to see if the idle changes. If it does then you have found an intake leak.

 

that only works if it's a vaccum leak at the gaskets, if it's a fluid leak like coolant into the intake casing smoke that test won't tell him anything.

 

The black smoke is normal wot The puff of white can be caused by rings not fully seated mositure in the air or a leaky head gasket. I'd suggest you keep an eye on the coolant level for a few hundred more miles and see if it changes alot if not you probably dont have any issues. Just keep an eye on everything new engines can do odd things while breaking in my engine made noise like the lifters were crap for almost 2k.

 

I wonder if it could be the builder forgot valve stem seals? I've come across a few times where a builder but the little black "rubber band" seals but forgot the umbrella seals.

Also on the babying thing, don't take my suggestion. But we take a cue from the motorcycle guys and rev the dog crap outa a new motor. You get the seals and rings used to it and conditioned to it. We almost always find it grants more power, but again, don't try it on my suggestion.

As for your problem, take it back to the builder if you can. Having someone build a motor is too expensive to except crap.

 

I totally agree.When i cranked my new motor for the first time, i backed the car off the ramps, drove out of the garage, turned in the street and hammered it!!!!!It stayed together.... guess i built it right!

 

Here's the thing guys. Ever since I got this motor I have had a problem with the intake not sealing. I belive the rings have already seated because I pulled the plugs in the first couple hunded miles and the were fine just some black soot from the car running rich. Now I was told to torque these intake bolts down to 35-40 ft lbs per gm specs. Come to find out this week that weiand says to do the torqueing in steps. 10-15-25 ft lbs. This is the third time I have done this intake gasket and the leaks had finally stop externally but Im thinking the intake is over torqued and crushing the gasket causing an oil leak. There is oil on a good number of spark plugs threads not on the porclien. My coolant level is fine and has never moved but my oil gets comsumed depending on how hard I drive the car.

 

ya sounds like you got some leaks there. those guys above talking about romping on the motor right after getting it rebuild, is really not recommended, sure it might hold together, or it might not, the possiblity of breaking something is higher than not. its better to drive it normal for the first 500-1000 miles minimum to make sure you don't have coolant leaks or oil leaks. Thats how i tighten my weland intake down, so its prolly recomended, do you do your own engine work?

 

Besides having the long block built I do the rest of the work on my car.

 

then it just depends on what you want to do? taking in manifold off isn't hard as you know, the worse part is changing the oil lol.

 

Yeah I have the intake down to a science now and can change everything in under 45 minutes. Really dont even have to change the oil becuase of the way I remove the coolant from the intake and heads. But I still do it just to be safe.

 

Well thats good that your being safe. it probably takes me about the same amount of time to take mine off, a little longer to put it back on, i always seem to misplace something (bolt, vacum hose, etc)