Thread: Ring gap for boost?

Is the ring gap checked with the rings seperated from the piston (loose on the piston) before putting them into the cylinder?? Checked right out of the box basically?

no. you put them down into the cylinder bore, use the top of the pistons to push them down into the bore until you at least get the skirt of the piston in the bore and then check them. This makes sure the ring is sitting flush and not at any angle in the bore. Then take a feeler gauge set and check what the gap from end to end is. File as necessary. Again if your machine work is good and your p2w clearance is good your rings right out of the box at least the ones from CP from my experience are almost always dead on the money.

Its always good to double check though as it doesnt take long. You only file the top and secondary/scraper rings. The oil control rings are preset.

I agree here. But JE, Wiseco, CP, all use Hypereutectic levels of silicon in their forgings. Arias and Ross have low silicon alloys for their pistons.

But keep in mind, having hypereutectic levels of silicon (~12%+) doesn't mean they will expand as little as the factory cast hypereutectics. The alloy will still expand more and will need more clearance.

Look up the pistons you have and compare them against the specs I listed. You will find them dead on. I promise.

theres a specefic spot for each rings ring gap. i dont know where they actually are as ive never gapped aft pistons or any pistons my self for that matter. but to the original op be aware of this.

im sure coheed knows what im talking about and can let you know.

stratton.

You mean the orientation of the gap?

yes.

stratton.

edited first post...I found it! Thanks for all your help guys!

I wouldn't worry about where the ring gaps are placed in relation to each other. The rings rotate in the bore around the pistons anyway.

but measuring the gaps needs to happen at several spots in the bore. A lot of guys recommend measuring at the top of the bore about .5" from the top where the ring sits at TDC and doing the gap-fitting there. It makes sense though, that is where the piston rings get hottest. Just as long as the machine work doesn't have a lot of taper in the bore. The smallest variance in taper will cause the ring gap to increase in relation to pi. so .001" in taper would mean you would possibly need to alter the gap by .0031". This is why it is so important to fit rings for the bore they are going to be used in.

rings will rotate only so much and then find their home. the rotation is caused by newly honed cylinders. i line them up with the spec from the fsm( stock and aftermarket) i agree with the .017 and .019. i have used those same gaps in the past.

are those specs, .017 top ring and .019 bottom ring, based on an 86mm bore?