CTT with new short block - still burning oil
 

Long story short:
My '07 CTT 957 (Euro model) with 77,500 miles today, started burning oil around 74,000 miles.
Changed coils and plugs
Changed air-oil separator
Issue persisted and then got worse (rough idle, CEL, ...)
Bore scope revealed scoring in cylinders 5 and 8
New short block was installed (new block from Porsche with pistons, camshaft etc)

Since then I have done 800 granny miles (never in sport mode, plenty of time to warm the engine and the oil, hardly ever use the turbo's in acceleration, etc.).

I noticed a fair amount of smoke under acceleration during these 800 miles, at least until the engine was thoroughly warmed up.
Yesterday, the 'check oil level' came on after 800 miles, which means I have burned approx 1.5 qt of oil in 800 miles.
That seems like an awful lot for a new engine.
What should I be looking at when I take it back to the shop on Monday?

The rings don't seat proper when you break in like that. What type of oil is in it? If synthetic that's too slippery for break in. Problem is it's under warranty so it's really not your problem.

All the keyboard mechanics are going to flame me for saying this. I would change to a conventional plain Jane oil and drive the piss out of it. If your lucky the rings might seat. When it stops smoking and burning oil switch back to synthetic. If you take it back to the dealer make sure it has the factory fill and keep your mouth shut.

DO NOT OVERHEAT IT!

Wouldnt the dealership that installed the engine do the initial break in? That usually is running it for a set time at increasing RPM over 20 minutes or so, ending at a couple minutes around 4000 or 4500, all to get the rings to seat.

Re: Wouldn't the dealership that installed the engine do the initial break in?

NO! The engine would have to be cycled under load with a dyno. Dealers don't normally have this equipment.

What J'sWorld recommended is the best way IMO.

Be prepared for a runaround. My wife's new MB CLK350 burned 1qt. every 500 mi. MB said this was normal for a high performance engine. She sold it after 1 yr of this nonsense.

Thank you for the feedback. In any case after 1300km (out of a recommended break-in of 1500), I should be able to drive the piss out of it. The question is: will that do anything to seat the rings at this stage? (forgive me if that sounds stupid. I am mechanically challenged :) )

I agree. Drain the oil that's in it, and keep it so if the rings don't break in and seat right, you can put it back before returning to the dealer. Then get some break in oil. I like Joe Gibbs Racing BR30 or BR40, depending on which weight you want to use, which are their Break-In oils. Run it as Jayme says and see if the smoke and oil consumption change. After a few hundred miles, it should be better.

Yup. Put some break in oil in it and drive it like you stole it. DE is a short trip away from anywhere in NL so you can break it in without the hassle of keeping the speed limit

FWIW, I broke mine in on Walmart Supertech 5w30 with a zddp additive. Mines built really loose and I don't burn any.

^^^This

I'm curious, what does the factory do about ring seating on new engines when it is factory filled with synthetic?

I would guess they run the break in at the factory with a conventional break in oil, then drain and replace that with the factory fill synthetic that is in the car when the buyer takes delivery

I've been to the factory for a tour. They fill it with the oil that is in it when you buy it. They do run it on a Dyno to check systems for about 5~10 min but don't really do any other kind of engine break-in. After the systems check if all is Ok it is pulled out of the factory to the big lot. A random vehicle used to be run on a small outside course with man-made bumps and seams to check for squeaks. This was 10yrs ago, Lupo may know more since he's a lot closer.