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Piston Ring question #103686
08/12/08 09:41 AM
08/12/08 09:41 AM
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texas
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Warrant_Officer Offline OP
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I have a question, I was checking the rings on my stroker kit, and found that the top rings are tight..should I file them to specs?? the specs on the paper listed are .005..does this sound right?? is this common?? it is a 340 bored 60 over. thanks again moparts..

Re: Piston Ring question [Re: Warrant_Officer] #103687
08/12/08 10:13 AM
08/12/08 10:13 AM
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Lincoln Nebraska
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RapidRobert Offline
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that is correct.they are 5 thou over so that you can file fit them to get your ring gap where it should be. .016" would be a ballpark figure for your top rings & KB hypereutectic pistons have different gap requirements. I would use a ring gap filing wheel & only grind on ONE end of the ring & slight deburring when you have the gap where you want it.


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Re: Piston Ring question [Re: RapidRobert] #103688
08/12/08 10:17 AM
08/12/08 10:17 AM
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So then..Im on the right track..I have been placing them in a respective cylinder mesuring them, and then filing them down on one side to the right gap, measuring them in the cylinder, it states that .005 is the min..does this sound right??
thanks again..

Re: Piston Ring question [Re: Warrant_Officer] #103689
08/12/08 10:29 AM
08/12/08 10:29 AM
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RapidRobert Offline
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You're good so far and the .005 listed figure is the amt of oversize(circumference) these file fit rings are which means you have to squeeze it tighter to get it to fit into the cyl which reduces the end gap then you file one end to get the gap to where you want it which is a seperate math figure.(.004 gap per inch of bore for top rings is a ballpark figure) which would be ~.016 for you. and .003 gap per inch of bore on 2nd ring. BUT ring gaps are dependant on piston type,ring type, eng intended usage. What do you have.


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Re: Piston Ring question [Re: Warrant_Officer] #103690
08/12/08 10:31 AM
08/12/08 10:31 AM
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chicagoland,usa
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buildanother Offline
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.004 per inch of bore diameter is a decent rule of thumb, which should put you around .016". Different types of rings vary.

Re: Piston Ring question [Re: Warrant_Officer] #103691
08/12/08 10:32 AM
08/12/08 10:32 AM
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GomangoCuda Offline
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Quote:

So then..Im on the right track..I have been placing them in a respective cylinder mesuring them, and then filing them down on one side to the right gap, measuring them in the cylinder, it states that .005 is the min..does this sound right??
thanks again..



NO. What exactly do the instructions say? You may be misunderstanding them. .005 ring end gap can't be correct. This is a recipe for disaster. I think RapidRobert is probably correct in saying that the .005 is saying the rings are .005 oversize to allow for file fitting. The correct end gap will be at least .016.

Last edited by GomangoCuda; 08/12/08 10:39 AM.

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Re: Piston Ring question [Re: GomangoCuda] #103692
08/12/08 10:42 AM
08/12/08 10:42 AM
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Crap..Im running home during lunch to get check my paperwork..I wasnt sure about this..thats why I had to ask the questions and get opinions from you guys.. I know that my top ring was too tight so I figured they were too big...but I remember there were a specific type of ring, and there was a side measurement and a back end measurement...my middle ring fit perfect...but not my top ring..go figure?..thanks again..

Re: Piston Ring question [Re: Warrant_Officer] #103693
08/12/08 11:51 AM
08/12/08 11:51 AM
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There is a big difference between engine assembling, (knowing where the parts go and sticking them there) and engine building. (knowing how each part works and making sure they do it at least as good as the factory designed them). Please be careful, get the book by Szylagi (IIRC correct) and read it first. You will cost money, and maybe really disappoint yourself if you make a mistake from ignorance. Just trying to save you efforts later. Also, there are right and wrong ways to file a set of rings. Again, you should get teh book and make sure you're doing it right.


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Re: Piston Ring question [Re: GomangoCuda] #103694
08/15/08 02:08 PM
08/15/08 02:08 PM
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So if the top ring is 0.16, then what is the average second ring gap on a standard 4 inch bore? 0.20?
thanks moparts..

Re: Piston Ring question [Re: Warrant_Officer] #103695
08/15/08 03:04 PM
08/15/08 03:04 PM
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RapidRobert Offline
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AL what you are trying to do is when the eng heats up you want the gap to end up being as close to(but definitely not at) zero as possible as zero gap leaks less compression. the 2nd ring doesn't get as hot because it is farther from the fire so it needs to be closer to zero to start with because it doesn't expand outward (which reduces the gap)as much so it's gap is .012".


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