Ring end gap
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Ring end gap

  1. #1
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    Default Ring end gap

    454 .060 over, bore is 4.311. SRP pistons, flat top.
    JE is not specific in their literature for marine use. The only category I thought came close is circle track/drag race that comes out to .0237, top and .0245 second. What is current thinking, less, or add more to both, open second only .003-.005 more?
    This a mild build, V-drive Ski/hotrod.

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  3. #2
    Foxwell Motorsports
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    Quote Originally Posted by badbehavior View Post
    454 .060 over, bore is 4.311. Srp pistons, flat top.
    Je is not specific in their literature for marine use. The only category i thought came close is circle track/drag race that comes out to .0237, top and .0245 second. What is current thinking, less, or add more to both, open second only .003-.005 more?
    This a mild build, v-drive ski/hotrod.
    .025/.028
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    FAst Reply!!!! SEnd the consulting bill, and thanks.
    BB

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    Quote Originally Posted by steelcomp View Post
    .025/.028
    isn't it funny how the technology has changed on the ring gaps- I remember when I built mt jetboat motor, the spec sheet stated somthing
    like .016/.018 for supercharger use( this was prob. 16yrs ago) for the speed-
    pro file fit moly rings, and just earlier this year, I happened to look at the sheet again in a new set of the same rings, while assembling another
    blower motor- and the recomended gaps were much larger for the second
    ring! had read up on this a couple of years ago, but never thought much
    about it- I generally set my ring gaps on the wider side anyway, but it
    was somthing to think about! (ps, steel-you were right there with that!-
    I was gonna say .026/.028) least that is what I set the last motor at)

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    Default ring gap

    Last motor i built it was a year ago using je rings and they still said 16,18 i would go with what the ring sheet says i dont remember but you will have so much gap per cubic inch

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    Quote Originally Posted by matt wheeler View Post
    Last motor i built it was a year ago using je rings and they still said 16,18 i would go with what the ring sheet says i dont remember but you will have so much gap per cubic inch
    More like gap per bore dia. in inches (based on the bore circumference and known ring growth per degrees of heat)
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    Senior Member wagspe208's Avatar
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    Let's throw a monkey wrench in the works just for giggles.
    At what RPM is it beneficial to make the 2nd ring gap bigger to prevent unseating of the top ring? Is this the case for every engine and every rpm? What about gas ported pistons? And what is the deal with gapless rings? Like Childs and Albert or Total Seal? And does compression ratio have anything to do with second ring gap bigger?
    (ok, start doing this now)
    Wags
    Last edited by wagspe208; 04-24-2010 at 09:40 PM.

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    Quote Originally Posted by wagspe208 View Post
    Let's throw a monkey wrench in the works just for giggles.
    At what RPM is it beneficial to make the 2nd ring gap bigger to prevent unseating of the top ring? Is this the case for every engine and every rpm? What about gas ported pistons? And what is the deal with galess rings? Like Childs and Albert or Total Seal?
    (ok, start doing this now)
    Wags
    You need.....a hobby.

  10. #9
    Senior Member wagspe208's Avatar
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    Quote Originally Posted by Fiat48 View Post
    You need.....a hobby.
    LOL.
    Sorry. I just had to ask.
    Wags

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    Senior Member fc-Pilot's Avatar
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    Quote Originally Posted by wagspe208 View Post
    Let's throw a monkey wrench in the works just for giggles.
    At what RPM is it beneficial to make the 2nd ring gap bigger to prevent unseating of the top ring? Is this the case for every engine and every rpm? What about gas ported pistons? And what is the deal with gapless rings? Like Childs and Albert or Total Seal? And does compression ratio have anything to do with second ring gap bigger?
    (ok, start doing this now)
    Wags
    Wags you kill me. But at the same time you bring up some good points to ponder. Since I am a nobody I am sure my thoughts don't count, and I don't have much experience with all of those combinations anyway so I don't really have any real data to back anything up.

    I also have to compliment you on your thread jacking skills.

    Paul

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    Senior Member wagspe208's Avatar
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    Quote Originally Posted by fc-Pilot View Post
    Wags you kill me. But at the same time you bring up some good points to ponder. Since I am a nobody I am sure my thoughts don't count, and I don't have much experience with all of those combinations anyway so I don't really have any real data to back anything up.

    I also have to compliment you on your thread jacking skills.

    Paul
    LOL Paul...
    I honestly do believe these are valid questions.Especially larger 2nd ring gaps for low rpm, low compression engines. Then, does engine hone and ring material matter. How about ring width. If using a 1.5mm ring on a 6500 rpm engine what then.
    I think the bitching is actually a sad thing.
    Personally I'm close to steel's numbers. A few tighter probably.
    Just finished one for a big heavy Baja. SRP pistons and rings. I also built the engine this one is replacing. It had no signs of ring butting.
    Hell, it only turns 4800 rpm or so. It broke a hyd. lifter. (owner supplied cam and lifters, and springs) (to much camshaft I said but what do I know?) The owner is a guy that cannot leave anything alone. He felt he needs to adjust the hyd lifters every year. They make noise upon start up (duh) he tightens them down some more. Guess what finally happened?
    Wags

  13. #12
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    (IMHO) this all depends on 'cylinder bore taper', and very little more. How much 'travel' do GAPLESS RINGS have in the same bore as 'normal rings', ? For example: .003" taper will SWALLOW a ring end gap of .012" . (.003" X 3.14 = 9.42"of gap claimed) So I still question what kind of quality machine work was done on your block prior to setting up you ring end gaps ? I have not even addressed the temps and materials growth factors yet. I set end gaps at mimimums for high temps (don't use gapless) and work with shops that produce very little tolerance in cylinder bore tapers. YES ! Blowbye may be a problem for some, but overall conditions lean towards 'less drag and more piston speeds' when drag racing boats. "So it uses a little oil on every pass', oil is cheaper than shortblocks".

  14. #13
    Distinguished Member David 519's Avatar
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    Quote Originally Posted by Fiat48 View Post
    You need.....a hobby.
    Pretty sure he has one, at least around here.....

    Quote Originally Posted by GFINISHLINE View Post
    (IMHO) this all depends on 'cylinder bore taper', and very little more. How much 'travel' do GAPLESS RINGS have in the same bore as 'normal rings', ? For example: .003" taper will SWALLOW a ring end gap of .012" . (.003" X 3.14 = 9.42"of gap claimed) So I still question what kind of quality machine work was done on your block prior to setting up you ring end gaps ? I have not even addressed the temps and materials growth factors yet. I set end gaps at mimimums for high temps (don't use gapless) and work with shops that produce very little tolerance in cylinder bore tapers. YES ! Blowbye may be a problem for some, but overall conditions lean towards 'less drag and more piston speeds' when drag racing boats. "So it uses a little oil on every pass', oil is cheaper than shortblocks".
    .003" taper!!?? Who would put something like that together?? If $$'s that tight, don't even bother to take it apart. I'd guess anyone paying attention to ring end gaps is also looking critically at bore roundness, taper and finish. If not, end gaps don't mean chit....
    We're trying our first set of gapless rings in a blown alcohol bracket engine. I've never run them before, but was persuaded to give them a try, mostly for alcohol dilution in the oil. So far, seems they are not much different than a standard ring for dilution, but a LOT more $$. We'll see as the motor gets some more passes on it.
    Quote Originally Posted by gn7 View Post
    ....... David 519 is 100% correct........

    Quote Originally Posted by fuelinmyveins82 View Post
    .....I think people forget that racing is supposed to fun. Losing shouldn't be discouraging it should motivate you work on your pile to make it faster.....

  15. #14
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    I just offered a point about 'relative measurements' and how ring end gaps may be effected. IMHO this guy was asking about a "PLAY BOAT" and so I would also NEVER USE zero gap rings in a boat that might get header water backed up in the exhaust, possably back to the valves and cylinders. What you may do in a RACE BOAT (IMHO) may not live two seconds in a PLAY BOAT, that has water (too much) run thru the exhaust headers/system. I have read on piston instruction sheets to multiply the diameter by a factor and that number would be the 'ring end gap'. I don't often use that method, since I know what the sizes of the cylinder bores are before I start. But then again, some people need a place to start. IMHO, measuring 1" below the deck and 1" above the bottom of the full cylinder bore, will give an accurate measure of the cylinder taper in a given hole. IMHO, how those measurements CHANGE under heat and loading is why we must have 'ring end gaps'. "I like them tight, without the use of zero gap rings', just my opinion".

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