Question about piston clearance!

97af · Post by **97af** » December 17th, 2008, 8:55 pm

http://www.wiseco.com/PDFs/Manuals/RingEndGap.pdf

M.F.D.B. · Post by **M.F.D.B.** » December 17th, 2008, 9:09 pm

Makes sense... but WTF does Wiseco know?

97af · Post by **97af** » December 17th, 2008, 9:18 pm

M.F.D.B. wrote:Makes sense... but WTF does Wiseco know?

Well we'll go with this one then.

http://www.aa1car.com/library/ring_end_gap.htm

A copy and paste from a Speedpro .PDF

Notice: Most of the second ring gap recommendations are larger than the top rings. Recent testing has proven that a
larger second gap increases the top ring's ability to seal combustion. This larger "escape" path prevents inter-ring
pressure from building up and lifting the top ring off the piston allowing combustion to get by. Many engine builders
have reported lower blow-by and horsepower gains at the upper RPM ranges with wider second ring gaps. Also,
almost every new car made is using this inter-ring pressure reduction method to lower blow-by and emissions and to
increase engine output.

dannygraves · Post by **dannygraves** » December 17th, 2008, 9:24 pm

um, I didn't look at either of the links, but if I remember correctly, having more gap on the top ring can cause ring flutter in the 2nd and create a bunch of pressure between the 2 rings which would cause all sorts of blowbyand ring seating issues.

Post by **AlisoBob** » December 17th, 2008, 9:24 pm

97af wrote:
M.F.D.B. wrote: If you had 2 ring gaps one bigger then the other you should have put the larger gap on the 1st position.
Justin,
Bigger gap always in the second groove......

This debate bounces back and forth every couple of years...

One side states you want the bigger gap on top , to deal with the heat of combustion.

The other side states you want the bigger gap on the bottom to help the top ring seal better ( the rings are held against the cyl. wall by the difference in pressure above and below the ring. If the bottom ring seals too well, the pressure above and below the top ring can be nearly the same...... and not seal for shit....)

All the fast guys I know are currently subscribing to the larger gap on the second ring theory....

These are 4 strokes though....

Who the hell knows, as long as they dont butt, your good.....

dannygraves · Post by **dannygraves** » December 17th, 2008, 9:24 pm

shit, you posted while I was typing...yeah, what he said..

britincali · Post by **britincali** » December 17th, 2008, 9:25 pm

Ive never gapped a ring, IMO if you dont check it theres nothing to worry about

Post by **AlisoBob** » December 17th, 2008, 9:27 pm

britincali wrote: IMO if you dont check it theres nothing to worry about

britincali · Post by **britincali** » December 17th, 2008, 9:27 pm

Bingo

M.F.D.B. · Post by **M.F.D.B.** » December 17th, 2008, 9:42 pm

AlisoBob wrote:
britincali wrote: IMO if you dont check it theres nothing to worry about

See my post below...

M.F.D.B. wrote:
ellett wrote:

How long before this starts leaking? Or just breaks-the-fuck-off?
He didnt notice it because it looks just like his teeth...

CR480R · Post by **CR480R** » December 19th, 2008, 5:42 pm

pstoffers wrote:If you divide 8x2 you get what?

Thats a joke right???

100hp honda · Post by **100hp honda** » December 19th, 2008, 6:25 pm

CR480R wrote:
pstoffers wrote:If you divide 8x2 you get what?
Thats a joke right???

i think he was saying if you have .008 feeler gauge in there you should have roughly .004 on each side

CR480R · Post by **CR480R** » January 9th, 2009, 11:46 pm

100hp honda wrote:
CR480R wrote:
pstoffers wrote:If you divide 8x2 you get what?
Thats a joke right???
i think he was saying if you have .008 feeler gauge in there you should have roughly .004 on each side

that is the wrong spot to measure and feeler guages are useless for bore measurement... but in theory if you had .004" on each side that would be .008" clearance... .004+.004=.008

BannedCR500Riders.com

Question about piston clearance!