Thread: Top cylinder bore ridges

I got a sr20det with low compression in cylinder 3.

The top cylinder bores have slight ridges, but those ridges are only on the edge of the bore, (sorry I did not took pictures of the ridges)

Anyway, where the head gasket sits and seals is smooth So my question is would those ridges be the reason for low compression?

1) Will I need to re-bore the block? or re-ring and call it a day.

2) What are your past experiences with similar issues?

(the engine was only compression tested and I have not fire it up, just torqued the cylinder head and comp tested)
3) Will the New head gasket be good still to re-use?

bump

What did you do to the motor?

Did you do a semi rebuild?

Did you buy it like this and want to know what to do?

A leakdown tester is the best tool. you can see if the rings are leaking or leaking from the intake or exhaust valves.

Its been my daily driver and weekend warrior for over two years.

Been runinig good until recently, it been boosted up to 15-16psi from a T28 at the track several passes.

So I guess its time its up, I already know its not the valves because I tested it with a good det head.

And the same cylinder is only pumping 60psi.

The ridge is just the difference in cylinder bore from wear. Depending how sever it is, yes it'll need to be bored to get the cylinders true again. Although the cylinders should all wear evenly. So if you have low compression in just one cylinder I'd suspect another cause. Either valves or gasket issue?