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Discussion Starter · #1 ·
I bought an old 1977 Polaris colt for $100. They thought it needed crank bearings. So tonight i split the whole engine in two. It needs 2 crank seals but no bearings..However when i pulled one of the cylinders off there was two deeep scratches. One of the wrist pins came out and wore deep scratches in the cylinder bore. Now the guy I bought it from ran it all last winter like this...He must have bought it from somebody who wrecked it, put a new piston, slapped it back together and sold it as quick as they could. The engine has a brand new piston. There wasnt even carbon on the top when we took the head off..how could he run it all winter and not carbon the top of the piston? Must not have run very well because there wouldnt be enough compression to push the gas up to the transfer ports..

Anyway..i dont want to spend any money on this old thing. They say JB weld will fix cylinder sleeves...but does it? Has anybody heard anything on this? Thanks!
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go to a junk yard and get a new cylender a sled that old it won't cost too much.
 

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When they say cylinder sleeves they ment hydralic cylinder sleeves.

The heat from the piston will cause the resin in the jb weld to re-activate and will come apart and fuc* up your piston and cylinder even more.
 

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Discussion Starter · #4 ·
but isnt JB weld good for 300 degress celcius? thats 630 degrees f. An engine doesnt run that hot...my buddy put JB weld on his Exhaust right on the manifold and it held..I put jb weld in the cylinder tonight neway. I'm gonna give it a try..
 

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oh well your call... jb weld is only resistant to 500 F not 630.

Quote. From JB weld company itself.

Not recommended for use on manifolds, exhaust systems, and other engine components which normally operate at temperatures above 500º F. Cylinders to exceed 500 F internaly.
 

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Discussion Starter · #6 ·
And does a 340 cylinder run that hot? I was told all the heat is at the top of the piston and that's only there for a fraction of a second. If the cylinder got 500 degrees you wouldnt be able to touch it. Im just trying to compare what i've heard to what you people have to say. Thanks for the imput!
 

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Discussion Starter · #8 ·
hahaha...i wonder how many times I can drive it back and forth to the road every morning and night to put it to the road for sale...lol.
 

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Your piston can get hot enough to melt the aluminum, which exceeds 1300 degrees. I have seen exhaust gas temperatures 8" from the piston at the probe on my sled that are even hotter than that. If your temps were only 500 degrees, the engine would be running so rich you would not be able to move. Honest.
 

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Discussion Starter · #10 ·
Ok! thanks for all the replies. My friend told me today that he found a 340 engine for sale for dirt cheap. The JB wont hold neway!
 
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