I've had the block out of the car for over a month while getting some headwork done and just noticed this today. There are several vertical grooves in the cylinders, towards the very top. You can barely see them, but if you run your fingernail across it will snag on it. Any idea what would cause this? Looks like I'll have to bump up to 85mm pistons.

 

I wouldnt boost on 85mm sleeves. Perhaps improper ring installation caused it?

 

Explain why you would not boost on 85mm sleeves? It seems to almost be the de facto 'dream build' here on HT (9:1 84.5mm sleeved GE block , me included)

 

1 grove per cylinder?

 

sam 85mm sleeves hold. jasons been doing it at 25 psi on a t61 in his crx for all season, 10.2s street car 10.2s.

brian as for the grooves, its likely that a ring may have broken or that a piston is damaged. If the ring gaps were done incorrectly or the installation was incorrect they can shatter.

remember sam?


[Modified by FFgeoff, 1:49 AM 10/1/2002]

 

I haven't had a chance to look over everything yet, but they seemed to be on all of the cylinders. I'll go over everything tomorrow and post what I find.

 

Marks in your cylinders probably from the rings. If you file the gap, you must debur them before installing them on the piston. Also could be from an overlapping oil ring but prob from the upper rings. Either bore it and install new pistons and rings or leave it alone as it has probably deburred itself using the cylinder wall.

 

vertical ones could have come from the ring compressor