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3.3 that has new piston and sleeve which makes it a 3.7 it was broke in with 33% i want to run 20%. someone told me i had to put a washer under the head. is this correct???
 
a guy my dad works with is rebuildin it for me and he said it made my 3.3 into a 3.7... i will try and find out for you. has anyone ever heard about the washers under the cooling head??
 
Shims under the head. I've never heard of this mod, nor does it sound smart. More pressure on the conrod and bearings in a 3.3 is asking for trouble. That and the sleeve is gonna probably hot-spot, too. Among other things.
 
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You don't need to play with the shim. If the sleeve's too thin, some spots on it will get hotter than others. Causing warps and other carnage.
 
Normally you don't need to add any head shims if you go down in nitro, if anything you "could" take one out but that's a whole other story. Your going to need more then just a piston and sleeve if this guy is able to do what he says, I'm curious what he has planned.
 
me too! i flipped it with out the lid on it and the air filter popped off well sand got in the carb and scratched the sleeve. so he said he rebuilt it. the motor run good after that but i should have it back by maybe tuesday or wednesday so i will see if i can tell any differnce. no one has ever turned a 3.3 into a 3.7???
 
i'm not sure. is there even a piston and sleeve that does this?? i havent seen my maxx run in about a year becuz i started racing lawnmowers. this guy my dad works with told him he would fix it for me. so i am not sur wat been done to it and wat hasnt.
 

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