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cylinder pinch

Old 11-06-2009, 07:43 PM
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e30nate
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Default cylinder pinch

can anyone reccomend a good place to send my piston and sleeve in to get re pinched. my engine needs a new pinch pretty bad. or is it something my LHS can do?
Old 11-06-2009, 11:06 PM
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j_blaze
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Default RE: cylinder pinch

why does it need a pinch?
Old 11-06-2009, 11:07 PM
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e30nate
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Default RE: cylinder pinch

it runs fine and has plenty of compression when its cold, but after about 10 minutes you have to keep it running and you can spin it very easily by hand
Old 11-07-2009, 10:12 AM
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Hoese37
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Default RE: cylinder pinch

sounds like a tuning issue to me.
Old 11-07-2009, 01:25 PM
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e30nate
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Default RE: cylinder pinch

If it was a tuning issue wouldn't it still have compression when its warm? After its warmed up it has almost no compression.
Old 11-07-2009, 04:40 PM
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insomnia1
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Default RE: cylinder pinch

here's a guy that does all our drag engines.i sent him a badly damaged abmods engine and you couldn't tell where when it got back to us.
http://www.rayaracing.com/
a 60 pmh head-on crash and running wide open throttle upside down for almost a minute.the sleeve had scratches, a few deep grooves and there was a wide black scuff mark on the side of the piston
damage looked very extreme and that $400 engine looked done for.
for $20 he was able to bring it back to almost new condition with no performance loss so far.
give ray a call.mine was pretty extreme.your engine should be no problem
clint
Old 11-07-2009, 08:35 PM
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apereira
 
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Default RE: cylinder pinch

There's no re pinch as such, your piston sleeve is worn, you just need to get a new one, to get the chrome back on the sleeve to exact dimensions is almost impossible.
To replace the piston sleeve is usual on worn engines, remember to change the connecting rod also when you change the piston/sleeve.

Regards
Old 11-08-2009, 12:05 AM
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insomnia1
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Default RE: cylinder pinch

i used to agree 100% with the whole rebuilding thing...untill i got some engines repinched by ray. hey for $20 give the guy a call.it sure beats what???..$100-$130 for a new p/s
FYI we run 50% nitro with 6% oil in these engines.i did change the bearings and con rods on all our engines when they were repinched. the piston and sleeves are holding up great.the pinch is good and compression is great and this is after 40+ passes on each engine
AND NO!! i will not get them repinched a second time!!!! i'm cheap...not crazy
clint
Old 11-08-2009, 12:09 AM
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e30nate
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Default RE: cylinder pinch

Yeah I'm usually all for rebuilding, but it was a free engine that's discontinued, so finding a piston set is nearly impossible
Old 11-08-2009, 12:48 AM
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insomnia1
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Default RE: cylinder pinch

there you go[8D]. for just bashing on 20% nitro no biggie right?.we had five different engines done so far.that TZ was an extreme case.the first repinch was a MEDIUM repinch( he gives you a choice.mild,medium or heavy).the second was a heavy.
that my friend adds up to alot of repinching
we had to preheat with a blow dryer just to spin that sucker over[X(]
i let the kids beat the hell out of it..about 30 passes on 50% nitro and it still runs very low 2's when they're not crashing it!!! too much power for a rj speed dragster
that engine and two others are going into three smartech cars running 30% nitro next year
like i said...i wasn't too keen on this whole repinching thing...untill i tried it.
if it's done by a pro the right way it's pretty tough to beat
clint

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