TeRC_FK Posted November 21, 2012 Report Share Posted November 21, 2012 I'm rebuilding my top end for the first time. I've got a Wiseco piston kit that states the minimum ring gap. What should be the maximum gap? Quote Link to comment Share on other sites More sharing options...
dirtydownunder Posted November 21, 2012 Report Share Posted November 21, 2012 i dont know what the max is on wiseco piston rings, some factory service manuals have max ring gap for stock piston rings but i dont think wiseco do. you just make them as close to minimum as possible, maybe around .002" more if ya gonna rev the absolute fuck out of it (more if boost/n2o is used). sometimes the rings you get are bigger, so you just have to run them or keep buying rings untill you have to file some down. on my 68mm bore, over 4 or 5 sets of rings, all were .003-.004" over minimum. wanted to run .013" but .016" was the tightest. Quote Link to comment Share on other sites More sharing options...
TeRC_FK Posted November 21, 2012 Author Report Share Posted November 21, 2012 Well Wiseco states that the minimum gap is .004 per inch of bore. So my gap should be around .01. Problem is that I gaped the rings to the smaller cylinder and now it's twice that. Quote Link to comment Share on other sites More sharing options...
okbeast Posted November 21, 2012 Report Share Posted November 21, 2012 You should be able to buy new rings. Contact whoever you got the pistons from, or one of the site sponsors. Quote Link to comment Share on other sites More sharing options...
TeRC_FK Posted November 21, 2012 Author Report Share Posted November 21, 2012 I called Wiseco and all they said was to get it pretty close. That's a bullshit answer. The gap is now twice the minimum it should be. I'm wondering if I have to buy new rings or if I could run it that way. The instructions say to increase the gap even more for modded engines but doesn't say how much. Quote Link to comment Share on other sites More sharing options...
Surfrjag Posted November 21, 2012 Report Share Posted November 21, 2012 whats your piston wall clearance if your rings are that far off? Quote Link to comment Share on other sites More sharing options...
Tedder Posted November 21, 2012 Report Share Posted November 21, 2012 Good question Surfrjag. Assuming all is good there... I've raced 1/4 mile asphalt for years and know from ET slips exactly what my bike will do. I also install new pistons and rings at the beginning of each new season. With freshly nikasiled cylinders I prefer to start on the tight side (.012) on my 68mm cubs but have been as high as .016 and not seen an ET difference or felt any performance was lost. Turbo and nitrous guys run larger gaps like DDU said.. Don't waste your money on buying more rings just because your a little wider than you'd like. Quote Link to comment Share on other sites More sharing options...
TeRC_FK Posted November 22, 2012 Author Report Share Posted November 22, 2012 Piston and rings are brand new and the cyclinder was bored to the piston. Piston clearance is not a problem. The reason the one set is so far off is because I wasn't paying attention and gapped them for the smaller cyclinder. When I tried to assemble everything, I realized what I did and I ended up now with a gap twice as large. I'm at about .02 now. Quote Link to comment Share on other sites More sharing options...
dirtydownunder Posted November 22, 2012 Report Share Posted November 22, 2012 Too large, get new rings. Quote Link to comment Share on other sites More sharing options...
Surfrjag Posted November 22, 2012 Report Share Posted November 22, 2012 Are both the rings that far off? If its only 1 i would put it on the bottom and run it. I doubt you will see any performance difference at all. Quote Link to comment Share on other sites More sharing options...
dirtydownunder Posted November 22, 2012 Report Share Posted November 22, 2012 no difference felt, but it wont last as long and its not balanced haha. youre building a motor, you wanna give it the best chance. you should buy the rings as punishment for making a mistake Quote Link to comment Share on other sites More sharing options...
TeRC_FK Posted November 22, 2012 Author Report Share Posted November 22, 2012 Alright. I'll just replace them. There only $30 shipped, a lot cheaper than another topend. Quote Link to comment Share on other sites More sharing options...
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