piston ring gap?
06-09-2010, 04:58 PM
#1
TECH Enthusiast
Thread Starter
iTrader: (32)
Join Date: Jun 2008
Location: Roanoke, Va
Posts: 514
Likes: 0
Received 0 Likes
on
0 Posts
piston ring gap? Aite got some manley rings and the paper says to gap the top ring at .055 and the second at .025 but ive always heard the second gap should be bigger than the first so not to trap gases. i called manley they said to cotact total seal and they told me .055 on the top and .035 on the second... so what should they be at? 3.905 bore mahle pistons t76 16-18ish pounds
thanks
thanks
06-09-2010, 08:11 PM
#2
Total Seal has a chart here:
http://www.totalseal.com/TechPage.as...plessPistRings
For your application I would use the "Nitrous 150HP+" settings but add in a bit more clearance for safety on those long roll races:
Top Ring: Bore X .008". Your Bore 3.905" X .008" = .032" (rounded up from .03124")
I'd add .008" and gap them at .040".
2nd Ring: Bore X .0055". Your Bore 3.905" X .0055" = .022" (rounded up from .0214")
I'd add .003" and gap them at .025" (as they indicated).
Oil Ring: minimum shown on chart + I recommend adding .007 = .022"
There are 2 schools of thought on top ring gap size vs. 2nd ring. I would go with the mfg. of the ring's recommendation. But .055" for the top is damn large.
Jim
http://www.totalseal.com/TechPage.as...plessPistRings
For your application I would use the "Nitrous 150HP+" settings but add in a bit more clearance for safety on those long roll races:
Top Ring: Bore X .008". Your Bore 3.905" X .008" = .032" (rounded up from .03124")
I'd add .008" and gap them at .040".
2nd Ring: Bore X .0055". Your Bore 3.905" X .0055" = .022" (rounded up from .0214")
I'd add .003" and gap them at .025" (as they indicated).
Oil Ring: minimum shown on chart + I recommend adding .007 = .022"
There are 2 schools of thought on top ring gap size vs. 2nd ring. I would go with the mfg. of the ring's recommendation. But .055" for the top is damn large.
Jim
The following users liked this post:
Jimbo1367 (09-02-2023)
06-13-2010, 03:33 AM
#5
how much can i spry Total Seal has a chart here:
http://www.totalseal.com/TechPage.as...plessPistRings
For your application I would use the "Nitrous 150HP+" settings but add in a bit more clearance for safety on those long roll races:
Top Ring: Bore X .008". Your Bore 3.905" X .008" = .032" (rounded up from .03124")
I'd add .008" and gap them at .040".
2nd Ring: Bore X .0055". Your Bore 3.905" X .0055" = .022" (rounded up from .0214")
I'd add .003" and gap them at .025" (as they indicated).
Oil Ring: minimum shown on chart + I recommend adding .007 = .022"
There are 2 schools of thought on top ring gap size vs. 2nd ring. I would go with the mfg. of the ring's recommendation. But .055" for the top is damn large.
Jim
http://www.totalseal.com/TechPage.as...plessPistRings
For your application I would use the "Nitrous 150HP+" settings but add in a bit more clearance for safety on those long roll races:
Top Ring: Bore X .008". Your Bore 3.905" X .008" = .032" (rounded up from .03124")
I'd add .008" and gap them at .040".
2nd Ring: Bore X .0055". Your Bore 3.905" X .0055" = .022" (rounded up from .0214")
I'd add .003" and gap them at .025" (as they indicated).
Oil Ring: minimum shown on chart + I recommend adding .007 = .022"
There are 2 schools of thought on top ring gap size vs. 2nd ring. I would go with the mfg. of the ring's recommendation. But .055" for the top is damn large.
Jim
for the top 0.018 & the 2nd ring 0.020
how much can i spry ??
06-13-2010, 07:55 PM
#7
Thoes numbers sound quite large. I'd be worried about oil consumption. Granted, the rings need the proper spacing to expand and seal properly. I'm looking at running 17-18psi on my forged 370 and top ring is a hellfire gapped to .024 and .026 for the 2nd I believe.
Trending Topics
06-13-2010, 10:54 PM
#9
06-13-2010, 10:58 PM
#10
Jim
06-14-2010, 03:37 PM
#12
.040" Top
.025 2nd
.022 Oil
That's my recommendation based on the Total Seal site calculations and your proposed boost level.
Speed-Pro advocates a larger 2nd-ring gap for their rings, but since you have Total Seal, I would expect they know their rings better, so I would hate to second guess them.
Jim
.025 2nd
.022 Oil
That's my recommendation based on the Total Seal site calculations and your proposed boost level.
Speed-Pro advocates a larger 2nd-ring gap for their rings, but since you have Total Seal, I would expect they know their rings better, so I would hate to second guess them.
Jim
03-21-2016, 03:37 AM
#15
Better safe than sorry but unless it's a gapless top .040'' is WAY too much gap unless you have 4 nitrous kits on top of 80 psi of boost. IMO .026'' top is pretty safe... Past .030 is HUGE... .016 would make me a little nervous but on under 10 psi with a really good tune and E85 it might be ok. I'd be really careful tho..
03-21-2016, 06:43 AM
#17
Restricted User
I always recommend standard windshield washer fluid injection on cast pistons. The water will keep piston temps down by a huge margin and the same with the top ring, keeping the rings from expanding too much from heat and causing destruction.
03-21-2016, 07:51 AM
#18
i have so many untouched motors on methanol going fast with no issues
now im tuning my pump only truck and butted rings twice easily
03-21-2016, 11:30 AM
#19
Thoes numbers sound quite large. I'd be worried about oil consumption. Granted, the rings need the proper spacing to expand and seal properly. I'm looking at running 17-18psi on my forged 370 and top ring is a hellfire gapped to .024 and .026 for the 2nd I believe.
