SlowPokeEg

D16z6
75.5mm Vitara + FJ bottom end
Stock head
Precision 5431 Turbo

Motor was completely rebuilt. Head was gone over, and longblock was assembled by local engine shop.

Ended up getting WAY behind schedule to finish it and didn't get it running until the night BEFORE the tune. It idled great and didn't leak, so we packed it up and trailered it to get tuned.

Tuner broke in the motor on the dyno, stating that keeping the car at 1500rpm or so for a certain amount of time will break in the rings. Also had 5w30 break-in oil in it. Car idled a little high (and somewhat surging) and he had to clock the dizzy way over which did not make sense!?!

Car did very poorly, only putting down 272/217 on 20psi. I was pretty heartbroken. It did puff a few clouds of smoke while tuning, but I figured it was still being broken in.

Well, after a tune, and 300 miles of pretty conservative driving (a few rips here and there), the car is now smoking like a freight train.

We thought it was either: Valve seals, Headgasket, Turbo, or rings.

Did a compression test tonight....
#1 - 145, 140
#2 - 155, 155
#3 - 190, 190
#4 - 185, 180

Added oil to 1 and 2......
#1 - 225, 200
#2 - 210, 200, 185

Obviously the oil is seeping past the rings since the numbers decrease each test


Are my rings garbage? Should I just change the oil and keep breaking the motor in and try again?

On a side note, my catch can is bone dry, which does NOT make sense if I'm getting that much blow-by. Also, when I pulled my plugs, they were maybe a little darker than they should, and smoke/vapor was fuming out of spark plug #2 if that helps diagnose it at all.

Thanks HT! I'm going to cry now.

SlowPokeEg

RLY?

wmac

sounds like your rings didn't seat.
i always heard you should vary the rpm during break in, w/lots of compression braking.
that's worked a couple of times for me.

SlowPokeEg

Well he kept it at 1500 for a while, then went right into the tuning session.

If they havn't seated by now, will they ever?

didurgf

blackeg

you might be past the point of being able to seat the rings still...a hone and new rings could be in order. interesting that they are the 2 adjacent cylinders that are bad... are you mixing oil and coolant by any chance?

SlowPokeEg

https://honda-tech.com/forums/forced-induction-16/bad-weekend-z6-2980677/


No, there was no mixing of fluids. Oil looked fine when I did an oil change after 300 miles of break in. Also, there was never any overheating of the engine, even though when I opened the hood it felt extremely warm.