Engine Question

[Dizzydean]

I broke a tab off a 440 piston during breakdown. Can I replace the one and have it balanced to the other 7? The piece was tossed so no repairs. Do I have to stay with the same brand/style? The have very small skirts. Not sure if a different make will throw things off balance wise. Thanks for any input.

 

[toolmanmike]

Ouch! To do it properly, you should find a exact replacement and have it balanced like the other 7 are. If you can't find a replacement something close will make the cylinder work but it might not be the correct way to do it. Had a friend with a 440-6 in a 70 Bee. It had one .030 over piston in it. It ran good but wasn't the right way to fix it in my opinion.

 

[krazykuda]

I broke a tab off a 440 piston during breakdown. Can I replace the one and have it balanced to the other 7? The piece was tossed so no repairs. Do I have to stay with the same brand/style? The have very small skirts. Not sure if a different make will throw things off balance wise. Thanks for any input.

It's best to match what the others are...

 

[Dartn440]

I agree with both above. There should be a part number stamped somewhere on the piston face, side, or underside. Interweb search. Choosing another piston is bad for balance as mentioned and potentially compression. Agree to rebalance etc. I ran into the need for this same thing once on a dropped valve and lucked out the Mahle sold my piston in a 1-8 quantity instead of by the set of 8.

 

[moper]

Get a new piston of the same part number and install it. No need to match anything if the part number is exactly the same. There's not enough difference IMO to necessitate a re-balance.