Originally Posted by
Cobra4B
What makes you say the cylinders are "egg shaped from the factory"? Oil consumption on LS1s is predominately due to the PCV system pulling oil from the valve covers. This is why the LS6 moved the vent to the valley cover under the manifold. The other issue was the lower tension oil control ring in the 2001 motors. For 2002 they modified the ring package and solved the issue. My car was re-ringed and uses maybe 1/2 quart between 5000 mile changes. It used to eat a quart every 1000 miles.
I've never heard anything at all about new motors having bad cylinder bores, or even them wearing oval over time. The only time that seemed to be an issue was in the early stroker kits. The excesive piston/rod angle was causing side loading at the bottom of the stroke and would wear out rings and ovate the bore.
That said... since you've got it this far torn down and the motor was so nasty inside might as well do it right and do it once.
EDIT: I've done lots of sustained high RPM driving with my LS6 and my father and have been around lots of HPDE LSX people. Very few have oil consumption issues once the PCV system is addressed and a catch can added.
Some people w/ aftermarket heads seem to have issues as the oil gets hung up in the heads with extended high RPM used and side G-forces, but drilling the lifter trays really helps that.... but again it's the rarity.
Smoking on decel is typically the PCV system gulping oil into the intake manifold.
The engine that was in my car from the factory smoked it's ass off on de-accel at the track. It wasn't uncommon for it to use a quart at a track rental. Didn't use it in normal driving. It has the LS6 valley cover and PCV catch can mod too. The engine I rebuilt that is in the car now had egg shaped bores before it was machined. It too was a factory block. It is a known fact that GM did not use a torque plate on the LS1's when they were building them. When I dropped off my LS6 intake with the OP I discussed this with him and he even mentioned see vettes that smoked on de-accel at track events that he was at.
I agree that the low tension oil rings were an issue also but not the main culprit. My car has Mahle rings in it now, forged pistons and was torque plate honed and uses ZERO oil, even at the drag strip under de-accel after a pass.
Bottom line, if you have it ripped this far apart, spend a little extra money and get some good machine work done. It makes a difference.
EDIT: With the engine apart the way it is now he can check for ovaling of the cylinder. All he needs is an inside micrometer and take measurements parallel to the crank and perpindicular to it in a given cylinder. Take them in three vertical locations in the bore. The measurements should be the same if there is no egging.
Waiting for Big Bake to chime in here....