Piston Ring Gap Questions/feedback
#27
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Re: PISTON RING GAP QUESTIONS
I did not set them yet as I am still waiting to bring my block to the machine shop to get bored and honed. Having a baby definitely limits my time.
#32
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Re: PISTON RING GAP QUESTIONS
Wish you luck, Is that a TAD on the tight side? I guess that's what your trying to figure out because it's not a track only race car. Hope you get some professional answers.
#33
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Re: PISTON RING GAP QUESTIONS
84.5 and supertech recommend .0045 for street performance (bore in inches x .0045 = top ring gap), came to .015 for the top ring, and .018-.019 for the second ring, and i allow .001 between all of them. I had one that was .014 and one that was .016. For the most part supertech's rings are usually perfect right out of the box as long as your machine work is good.
#34
Re: PISTON RING GAP QUESTIONS
84.5 and supertech recommend .0045 for street performance, came to .015 for the top ring, and .018-.019 for the second ring, and i allow .001 between all of them. I had one that was .014 and one that was .016. For the most part supertech's rings are usually perfect right out of the box as long as your machine work is good.
Im thinking going with
Top ring .019"-.02
Second ring .024"
Now is that to loose and give me any problems? As I said I don't really have a choice on going any tighter on the second compression ring.
#36
DO IT ON ALL FOURS
#40
Honda-Tech Member
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Re: PISTON RING GAP QUESTIONS
x factor
street performance .0045
moderate turbo/nitrous .0050
drag/overal track .0055
turbo/nos race only .0065
the calculation is bore in inches x factory = top ring gap
the second ring calculation is first ring gap x 1.25 = second ring gap
so...
with the measurements your showing on you rrings your gonna be setup between drag/oval track and race only ratings for the ring gap, remember these gaps are meant to account for the heat build up as the rings expand, race cars run constant WOT so the heat build up is much higher. On a street driven car that would just be way too loose.
With the measurement you posted 3.21 for bore size your gaps should be...
.016 for the top ring and
.020 for the second ring
and thats for moderate turbo/nitrous setup
thats what i would run, no way i would run the top ring gap at .020 for me personally, you would bleed off too much compression on a street car
#45
Moderator in Chief
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Re: PISTON RING GAP QUESTIONS
Spawne, His target goal is 400-500hp. I dont think thats a moderate turbo category in my opinion. I would recommend multipliers of .006 top / .0065 middle x bore.
That works out to be .019" top and .021" second ring gaps.
However your second rings unfiled are larger than your intended target gap. This is very common. I’ve seen this in multiple ring sets from CP and Wiseco too. The second ring isn’t very important as long as it's gap is larger than the top ring to prevent ring flutter. Just make the second rings all the lowest common denominator, .024". Or just leave em as is. You can try and get new rings, postpone your build another week but the new ring set will probably be the same.
That works out to be .019" top and .021" second ring gaps.
However your second rings unfiled are larger than your intended target gap. This is very common. I’ve seen this in multiple ring sets from CP and Wiseco too. The second ring isn’t very important as long as it's gap is larger than the top ring to prevent ring flutter. Just make the second rings all the lowest common denominator, .024". Or just leave em as is. You can try and get new rings, postpone your build another week but the new ring set will probably be the same.
#48
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Re: PISTON RING GAP QUESTIONS
Moderate turbo, the ring gaps are determined strictly by heat generated as the piston expands, the differences in gap are accounted for how long the periods are for prolonged WOT. You just wont see that on a street car. Short bursts of WOT wont generate the kind of expansion that those wider ring gaps require.