Ring end gap question

[95 gsx]

Im having a motor built and I specified that I wanted 0.005 per inch of bore on the rings. I stopped by the machine shop today to get an update and the machinist said he gapped the rings to 0.028 (first and second ring). I know the second ring is supposed to be gapped larger than the first but the first ring is already 0.010 more than what I wanted. Am I going to be seeing a lot of blowby with gaps this big? Should I just get another set of rings and gap them myself?

 

[Purevil]

Each piston manufacturer has different ring gap recommendations. Generally its something like 0.005" per inch of bore. This would give you 0.017". The second ring is usually just a couple thousanths different than the first. If you search around online most dsm's have gaps anywhere between 0.015"-0.030".

I'm sure your machinist knows what he is doing, if in doubt, ask him about the gap.

 

[95 gsx]

Well, thanks for the input. I just thought from what I read in the merged ring end gap thread that .028 was a little big. Ill run the motor and see what happens...

 

[99gst_racer]

Unless you plan to run a GT42r at 40 PSI, an .028 top is way too big. You will have more blow-by with lower cylinder pressures. If you're going to be less than 500HP, you would want something like a .017-.021 top and about .002-.005 larger on the seconds.

IMO, he screwed up and should -bare minimum- replace your top set for you.

 

[95 gsx]

Hmmm, I dont plan to be anywhere near 500 hp. I had a suspicion that the gaps were too big. Im going to buy another set of rings and start over.

 

[Talonracn50]

isnt that the spark plug gap? .028?