Ring end gap ?????
Thread Starter
Team Owner
Joined: Apr 1999
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From: Reno Nevada
2024 C3 of the Year Finalist- Modified
Ring end gap ?????
I was just doing some JE rings. Normally I just do a .030+ a few. These boxes of JE's ask for .040 top and .050 second ring end gap. Chromoly face 1/16 and d- iron 1/16th second.
This is for a motown 427 small block 4.125 X 4.00
Nothing but problems with Bill Michell Products.
This is for a motown 427 small block 4.125 X 4.00
Nothing but problems with Bill Michell Products.
Racer
Joined: Sep 2001
Posts: 354
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From: Prineville Oregon
Re: Ring end gap ????? (gkull)
George,
Are you stepping-up or is this for someone else? Different pistons have different thermal expansion rates. Try running a set of hypereutectic pistons...you can drive a Mac-truck between the top end-gap settings. :lol:
Deen
Are you stepping-up or is this for someone else? Different pistons have different thermal expansion rates. Try running a set of hypereutectic pistons...you can drive a Mac-truck between the top end-gap settings. :lol:
Deen
Drifting
Joined: Jul 2002
Posts: 1,820
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From: Puyallup WA
Re: Ring end gap ????? (gkull)
George, I am looking at the "Ring Installation Guidelines" that came with my JE pistons/rings. For "High Perf.Street-Stip" it shows a minimum gap of .0045" * bore for the top ring and .0050" * bore for the second ring.
On your 4.125" bore block this would amount to a minimum of .019" end gap for the top ring and a .021" for the second ring.
Steve
On your 4.125" bore block this would amount to a minimum of .019" end gap for the top ring and a .021" for the second ring.
Steve
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From: Corsicana, Tx
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Re: Ring end gap ????? (gkull)
That sure seems huge. I'm looking at my instruction sheet for my last JE/SRP rings and they show the alrgest possible combination being .0065 per inch for Chrome Moly ones even in blown or nitrous race deals. And everyone places them a little conservative and say even that is too loose. That only comes up around .027-.028 for the top and the second one at around .022-.024.
Are these some whiz bang high tech things? Sounds like they really subscribe to the large second gap theory!
JIM
Are these some whiz bang high tech things? Sounds like they really subscribe to the large second gap theory!
JIM
Race Director
Joined: Sep 2000
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From: The Top of Utah
Re: Ring end gap ????? (gkull)
End gaps of .040-.050 are HUGE. If that is really what it says, I'd be on the phone with J&E. The other numbers, .0045, etc, usually are a spec, more of a guide line, pertaining to the amount of gap per inch of bore diameter. A nominal. .004" gap per inch of bore equals a .016 gap on the subject ring, in a 4" bore. This is much closer to where you want to be. Re-read, both of you, and check other sources of info. .040 is about double what you want. .004 will seize the engine, in a heartbeat. Good luck, and...
RACE ON!!!
RACE ON!!!
Race Director
Joined: Jan 2000
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From: Corsicana, Tx
2020 C2 of the Year - Modified Winner
2020 Corvette of the Year (performance mods)
C2 of Year Winner (performance mods) 2019
2017 C2 of Year Finalist
Re: Ring end gap ????? (CFI-EFI)
You got my curiosity up some so I looked at some other ring info I had and I found some Speed Pro stuff that showed up to .009 per inch in ungodly blown/nitroused deals. That might put you around .037 or so, but I would really have to have a good reason to go that big. I suppose if I was running it on the edge of meltdown for a few seconds at a time and I knew the gaps would close up when pistons started glowing....maybe.
I'd be interested in what JE says. In fact their ring packaging sure looks like Speed Pro stuff anyway!
JIM
I'd be interested in what JE says. In fact their ring packaging sure looks like Speed Pro stuff anyway!
JIM
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Joined: Apr 1999
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From: Reno Nevada
2024 C3 of the Year Finalist- Modified
Re: Ring end gap ????? (427Hotrod)
We ended up doing .030 on each. This 427 motown small block is going to see lots of abuse. It's got lot's of good parts. We spent a good 6 hours just clearancing the 6 inch H beam rods and the threaded ends of the bolts.
Motown blocks are really nice units. The problem was the Comp Cams 1.050 base circle cam. My last Crane billet roller was only .950 inches. That's a full .100 difference that has to be made up by grinding off one side of every rod and a small amount off every rod bolt.
We had each piston in and out many times and just when we thought we had enough clearance when we went to the final 79 foot pounds of TQ on the rod bolt two more just gently touched the cam. So it was back out for more grinding to get at least .050 clearance on every one.
4 inch stroke small blocks with 6 inch rods are very custom built motors.
Motown blocks are really nice units. The problem was the Comp Cams 1.050 base circle cam. My last Crane billet roller was only .950 inches. That's a full .100 difference that has to be made up by grinding off one side of every rod and a small amount off every rod bolt.
We had each piston in and out many times and just when we thought we had enough clearance when we went to the final 79 foot pounds of TQ on the rod bolt two more just gently touched the cam. So it was back out for more grinding to get at least .050 clearance on every one.
4 inch stroke small blocks with 6 inch rods are very custom built motors.
