Why is this happening? i noticed its a greyish blackish smoke what could be causing this new motor with less than 10k miles and 15 50 mobil1 in it

 

Maybe it's runnin a little on the rich side, or you have no or bad catalytic converters.

 

or maybe a leaking fuel injector?

 

anyone else guys? i will be gettin a new tune this week it seems to be runnin rich as hell tho

 

why are you running 15/50 motor oil?

 

cus its a built motor? is it not good to be runnin that or what should i go back to 5w20?

 

Firstyour 15 50 is the wrong oil and not sure where you got the advice from but 5w 20 is the recommended for an LS1.

Second, if it only smokes on startup, it's usually and indication of bad valve guide seals or rocker bolts not sealed on ported heads. Need more info on the engine.

 

^^^^care to point out what page in your owners manual says 5w20???i just got mine out and its 5w30 or 10w30. thats the only two recommended.

 

motor doesnt matter honestly can u not run 15 50?!?!?!?!?!

Valve guides are 10k miles old as well.

 

50 is a little thick for an LS1. the tolerences are pretty tight in modern motors. 15W50 is also very thick on startup. however i dont think this is causing your smoking issues. before i had my car tuned, it would sit and blow rich smoke for 10 minutes after i started it. kinda like a grayish blue depending on how the light hit it.

if your dead set on M1, i would go with M1 0W40.
but if your willing to change, i would go with Castrol Syntec 5W30.

 

one more time....

 

cus i was havin low oil pressure issues. and yes i think my car is running a bit rich actually i know it is. so i will have it re tuned and get back with yall for the mean time ill change back to 5 30.

 

What are your bearing clearances? Just because its an LS1 dont mean you have to run a certain brand or wintergrade of oil. Most builders will recomend an oil with higher levels of zinc to help with break in. I run an 0-40 when its cold outside and a 15-40 summer time. Ive got 37,000 on my rebuilt and 150,000 on the clock total. You got a higher volume pump with a stiffer spring more than likely so that wouldnt be any problem. A thicker oil will will soak up a little of power, but will help quiten a noisy valvetrain. You can also get into a situation of running to thin of an oil for the street.

 

Oops, my mistake Not 15 50 though - of that I was sure.

Running rich will dilute the oil on the cylinder walls and cause it to burn but if it's only smoking on start up I would think seals or rocker bolts like I said.

 

i would not run 5w30 in a built motor unless you know the clearance specs.
its going to be a worn valve seal, or rocker bolts leaking. youve got a built motor, so im going to guess ported heads....
prolly nothing serious.