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piston skirt hair line crack.

4

48tony

Regular Contributor
ok here is somewhat of a dumb qustion. 2 out of my 3 pistons have a hair line crack.it is a looper 60 hp the crack is on the oppisite side of the exhaust port hole.witch i belive it would be the intake hole on the piston were the crack can be seen. are they junk. i was just going to change the upper crank bearing do to a slight chatter up near the flywheel.looks like i will need to go a bit deeper in my pocket if the pistons are unuseable. at this point i am going to mike the cylinders and see what i get for specks.if i am within specks should i just hone out the holes. and new rings or should i bore and go all the way. the new piston kit are not looper pistons. so it may run a little better with lower comp pistons do to todays gas vs the gas in 1970 . ive been told there is a converstion kit for the wrist pin bearing something about 5/8 vs 3/4. any one no about this. is the new pistons wrist pin smaler or biger. what was going to be a 200 dollar fix looks like i should add a few zeros
 
All 3 cylinder OMC motors are loopers, therefore your new pistons will be looper pistons. There is a bearing conversion so you can use the newer style 49 cid piston in an older 49 cid powerhead without changing the rods.

If your pistons are cracked it may be because the skirts and cylinders have worn past the tolerance and the piston is no longer supported correctly. You will want to bore any cylinder that gets a new piston. Once you measure the cylinders you'll probably see that they all need to be bored. Do not reuse a cracked piston, they very rarely heal themselves.
 
Very common for those pistons to crack, seen lots of them.----------------------------The new OMC / BRP pistons for those motors will be the thick wall replacements.
 
were is there a good site to go under for these pistons it is a 1970 60 hp esld. all the sites i go to they no longer have them in there stock.there is a place on ebay for i think all most 700 dollars i can get a powerhead rebuild kit. rods pistons wrist pin and lower con rod bearings gaskets rings.what does 49 cid mean. and are these the new pistons i will be looking for.i put the block in the shop to get the correct info on boring. even if i get by with honeing i am still going to need a lot of stuff to get.i have a allmost new crankshaft to use i picked it up from joe r on ebay so i at least have a start on new parts. any info on these parts i need will be helpfull
 
49.9 is the cubic inch displacement of your motor.------------$180.00 for a good used set of 3 standard bore pistons!
 
racer you have these pistons. do they come with con rods.and if so do i need to replace the lower con rod bearings.the main reason for this qustion is that those bearings have worn in on a diffirent crank. will it much matter putting them on a other crank you no what i mean.if you got all this then i will talk with you ok thanks.
 
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