Question : just-rebuilt 3.1 has insane oil consumption, smoke

[alex159569]

OK I'm getting seriously frustrated by this engine. 98 Grand Prix, bought with a knocking engine due to previous owner running with extremely low oil. pulled the engine, had the cylinders bored, installed brand new pistons/rings and all gaskets and valve seals. put engine in car, notice that it seems to be burning oil, though at idle none seemed to be leaking from the engine. drove for 2400 miles, engine ate a quart of oil every 100 miles (!), but only smoked when given gas around 3-4k rpms. also oil would turn completely black after driving for around 20 miles. measured compression on all cylinders, had 160psi. noticed that plastic LIM gasket was cracked, replaced with fel pro all metal one. same problem. took off intake again and noticed the fel pro gasket broke off (after only 100 miles of driving), then i found out the torque specs i was using were incorrect, I did 24 ft lbs on the LIM. got a 3rd LIM gasket, torqued to spec, engine still smokes. what in the world could be the problem? thanks for reading!

[Rootie524]

warped manifolds?

[alex159569]

warped manifolds?

you mean my intake manifold could be warped? what could have caused that? i might add that when i bought the car i drove it home despite the knock and didn't notice any smoking or anything unusual at all.

[Rootie524]

it's a possibility. but since it wasn't smoking on the way home, then probably not.

how much did you have it bored or do you mean honed? and if you had it bored..this might be really obvious..and sorry for asking, not trying to say your dumb but i have to check all possibilities..did you get pistons to match the bore.

and new head gasket and heads torqued to spec? resurfaced at all?

normally burning oil is either a valve seal or piston ring.

[alex159569]

it's a possibility. but since it wasn't smoking on the way home, then probably not.

how much did you have it bored or do you mean honed? and if you had it bored..this might be really obvious..and sorry for asking, not trying to say your dumb but i have to check all possibilities..did you get pistons to match the bore.

and new head gasket and heads torqued to spec? resurfaced at all?

normally burning oil is either a valve seal or piston ring.

i believe it was bored .020, and i bought pistons from the same shop that did the work for me so i'm sure they got it right. like i said, 160psi in all cylinders which i doubt would be possible with undersize pistons. also the car drives and sounds perfect, never any loss of power or strange noises. besides the oil consumption/smoke it drives like new. now one thing i didn't do was check the heads at all, nothing done to them whatsoever. torqued carefully according to the spec sheet i had, i can look up how much it was exactly but it was some ft lbs + 90 degrees on second pass. valve seals were replaced when engine was taken apart so it was quite foolproof, they all went on easy. and even if one valve was bad, would it be reasonable to have such ridiculous oil consumption? thanks.

[Rootie524]

did you have the block magnafluxed? sounds like a crack somewhere whether in the block on in the heads. like you said valve seals shouldnt yield that much oil consumption..

im no pro though..hopefully someone else can chime in. im just saying the things i would check for if it were me.

[60dgrzbelow0]

What if any "Engine Break-In Procedures" did you follow after the re-build? Can you see a dramatic fluctuation in your Oil Pressure from idle to higher RPM? If the block is cracked, there may be oil infusing into the water jacket column and making it looking "muddy". This can also happen vice-versa... resulting in anti-freeze getting into the engine oil and wreaking havoc on bearing surfaces soon after. In that case.. the engine oil gets turned into gooey "chocolate milk". The oil channels and galleries should not be getting compromised by either loose or ill fitting manifolds. When the engine is cold... open the radiator cap and have a look at the color and condition of the anti-freeze. If you pull the dipstick and can smell gasoline in the engine oil and it has gotten darker than it should be since your last, recent oil change... then fuel vapors and unburned hydrocarbons are getting past the piston rings and contaminating the oil with carbon and unburned gasoline fumes. Cracked rings, holes in the piston heads... or cracked engine cylinders are "The Usual Suspects" here...

[86FieroSEv6]

Say, who assembled it? Were ring gap orientation guidelines followed?