Piston cooling holes

[EncyclopediaRonnie]

hey guys was reading on another forum last week and saw an old post talking about ading a 3rd cooling hole in the piston skirt for motors with exaust bridges. i was wondering if any1 had more detail on this. my motors been sleeved so im really thinking a lil extra help wouldnt go astray but i dont wanna dramatically weaken my piston.

cheers guys

 

[whenfoxforks-ruled]

Stick with the piston and sleeve directions.

 

[RM_guy]

They are actually lubrication holes which in turn aids in cooling. They are only needed on cylinders with an exhaust bridge so they only need to be present where the piston overlaps the bridge when the piston is at TDC. If you add more towards to bottom of the piston and they are below the exhaust port then you don't gain anything. Adding extra ones won't hurt anything though even if they are below the exhaust port but I wouldn't put them any closer than what the piston directions say to.

 

[EncyclopediaRonnie]

okay well i dont have a massive exaust bridge but it do and i have relieved it but still kinda wanting that extra insurance i guess. ill have squiz at where they all are etc and decide i guess.


any1 done this before?

 

[placelast]

Wiseco instructions for RMX pistons instruct you how to put them in, and one should.

A circular hole will distribute force/stress equally, radially away and is therefore the best geometry to use in metals. I say it is safe from a metallurgical point; more so as Wiseco asks the installer to do so.

 

[whenfoxforks-ruled]

It is the skinny exhaust bridges, they move more than bigger ones. There are some that do not have it. Follow the directions. Why make it worse?

 

[EncyclopediaRonnie]

by no means want to make it worse im waiting on the new piston to see if it has them, the old 1 did but only 2 i was thinking a 3rd for that tad extra. but if it seems to be bit up in the air i wont i was wondering if it was a definet yeah do it big help sorta thing

 

[whenfoxforks-ruled]

2 is in the directions I know for a fact. If it has an issue, 3 will not fix it. Nor 4, 5, 6,,,,,,,

 

[EncyclopediaRonnie]

okies all good.