Thin vs. Thick Piston Rings
#2291588
04/21/17 02:47 PM
04/21/17 02:47 PM
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Joined: Jul 2011
Posts: 960 Chicago
PurpleBeeper
OP
super stock
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OP
super stock
Joined: Jul 2011
Posts: 960
Chicago
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I'm starting to look for forged pistons for a new motor with nitrous. Most of the forged pistons I see use 1/16", 1/16" 3/16" piston rings. I believe the stock pistons (& some forged) use 5/64", 5/64", 3/16" rings.
On a mainly street nitrous motor, what top/middle ring thickness is better? Why?
What other general knowledge about rings can you guys give me?
70 Roadrunner convt. street car
440+6, NOS, 4-spd, SS springs
'96 Mustang GT convt. street car
'04 4.6 SOHC, NOS, auto, lowered
"Officer, that button is for short on-ramps"
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Re: Thin vs. Thick Piston Rings
[Re: PurpleBeeper]
#2291603
04/21/17 03:11 PM
04/21/17 03:11 PM
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Joined: Aug 2003
Posts: 43,303 Bend,OR USA
Cab_Burge
I Win
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I Win
Joined: Aug 2003
Posts: 43,303
Bend,OR USA
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The thinner the ring pack the less drag on the cylinder walls, less friction = more power On your deal you need to make sure the pistons you buy are for street NOS, not stock or SS racing where the ring lands are raised way up to increase the compression ratio Are you planning on running a vacume pump? If so then look at the really thin racing rings like 1Mm or the .043 rings with minimal tension Those size rings make a huge difference on the ring drag
Mr.Cab Racing and winning with Mopars since 1964. (Old F--t, Huh)
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Re: Thin vs. Thick Piston Rings
[Re: PurpleBeeper]
#2291624
04/21/17 03:37 PM
04/21/17 03:37 PM
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Joined: Sep 2014
Posts: 4,457 Washington
madscientist
master
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master
Joined: Sep 2014
Posts: 4,457
Washington
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There is never a reason for 5/64 rings on anything automotive anymore.
It was overkill in 1970.
A 1/16 ring pack is as thick as I'd use in a street engine today.
Just because you think it won't make it true. Horsepower is KING. To dispute this is stupid. C. Alston
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Re: Thin vs. Thick Piston Rings
[Re: PurpleBeeper]
#2291743
04/21/17 07:26 PM
04/21/17 07:26 PM
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Joined: Jul 2011
Posts: 960 Chicago
PurpleBeeper
OP
super stock
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OP
super stock
Joined: Jul 2011
Posts: 960
Chicago
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I don't plan to run an evac system since this is a 99% street motor. It definitely makes sense that thinner rings = less friction. I've got 1/16", 1/16", 3/16" rings in the current engine with "low tension" oil rings. I swear my rings took 5000 miles to seat! One of the rings is chrome molly, if that matters.
70 Roadrunner convt. street car
440+6, NOS, 4-spd, SS springs
'96 Mustang GT convt. street car
'04 4.6 SOHC, NOS, auto, lowered
"Officer, that button is for short on-ramps"
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Re: Thin vs. Thick Piston Rings
[Re: PurpleBeeper]
#2292205
04/22/17 05:18 PM
04/22/17 05:18 PM
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Joined: Jan 2005
Posts: 12,424 Kalispell Mt.
HotRodDave
I Live Here
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I Live Here
Joined: Jan 2005
Posts: 12,424
Kalispell Mt.
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I am building a 5.7 eagle motor for my truck and the rings are paper thin and with 300,000 it still used no oil and there is no discernable bore wear when feeling it up, cross hatch right up to the top of the bore. One important thing though is the oil drainbacks on the outside of the head keep a lot of oil off the crank and therefore off the cylinder walls. A vacuume pump and good windage control can work towards the same end and the less oil on the walls the less ring tension needed.
On my 410 stroker I ran 1/16 rings low tension all around with a dykes 2nd ring and it has no blowby and no oil use at 11.5 compression on iron heads.
A nitrous motor may have slightly different requirements but I am no longer afraid of the thin low tension rings on the street or strip. I bet the hellcats are running a very thin ring also and giving you a warranty with it.
I am not causing global warming, I am just trying to hold off a impending Ice Age!
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Re: Thin vs. Thick Piston Rings
[Re: HotRodDave]
#2292213
04/22/17 05:30 PM
04/22/17 05:30 PM
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Joined: Jun 2012
Posts: 1,899 MYRTLE BEACH SOUTH CAROLINA
ek3
top fuel
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top fuel
Joined: Jun 2012
Posts: 1,899
MYRTLE BEACH SOUTH CAROLINA
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thinner ring sets are lower in drag yes. the important thing is to use a very good piston. this is because it is what keeps the rings seated "squarely" aginst the cyl. walls with all your new found pressure! good ring lands and a tight clearance and round cylinders will keep things from leaking. je makes a hardend ring set for nitrous and a great piston . I am biased to the mahle brand products myself. ditto on std. tension oil rings. and pleanty of end gaps...
Last edited by ek3; 04/22/17 05:33 PM.
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Re: Thin vs. Thick Piston Rings
[Re: Porter67]
#2292289
04/22/17 07:31 PM
04/22/17 07:31 PM
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Joined: Jun 2003
Posts: 52,972 Romeo MI
MR_P_BODY
Master
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Master
Joined: Jun 2003
Posts: 52,972
Romeo MI
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Being that the blocks are harder now days you can put in thinner rings and a bit less tension on them.. try to do this 40 years ago and you would have a 1/8" or deeper ring groove.. better quality parts on all the stuff now days.. hell 40 years ago a long life on a engine was 100K.. now days thats just broke in... LOL
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