Piston ring eaten by cylinder wall and ring gap

[markus_74]

Hello,

Sorry I can not send the post to merge with my old post so I alway make ne thread, I don't know why but the website prevent me to reply or quote to my thread before

I just open my m20 engine and I just check it with feeler gauge. My problem before is I lost compression at cylinder 4,5 and 6. I assumed that I have made mistake while reboring.

Yesterday I have finally open the head off and check the gasket is still good.

But after got inspection on each cylinder with used piston ring. I got data.

Cylinder 1 have 0.3 mm
Cylinder 2 have 0.3 mm
Cylinder 3 have 0.3 mm
Cylinder 4 have 0.6mm
Cylinder 5 have 0.6 mm
Cylinder 6 have 0.4 mm

I'm wonder why this can be happened? The ring number 4, 5 and 6 has eaten by cylinder wall, may be my theory was the bad honing pattern or too rough so it is rub the piston ring? Or may be the bore not round? Or the bore not straight 90 degree? I don't know may be friends here has any idea?

And now after I clean the block I try to measure the cylinder bore with new mahle piston ring.

I got at

cylinder 1 is 0.2mm
Cylinder 2 is 0.2 mm
Cylinder 3 is 0.2 mm
Cylinder 4 is 0.25mm
Cylinder 5 is 0.25mm
Cylinder 6 is 0.2 mm

Should I files all the gap so all will have same uniform gap to 0.3mm?

Or different between 0.2 and 0.25 is not too big so I will leave it as it is?

Thank you
Markus

[reggid]

someone with god like powers should merge this thread with the one in technical help...