need to rebalance

[Triz]

I have a stock explorer short block that has new bearings and rings put in it but the stock hyper pistons are still in use. My question is if I switch out the hyper pistons with a set of forged stock pistons I have, would I need to have the assym. rebalanced?

 

[Rick 91GT]

Yes it is very unlikely the weight will be the same between the 2 piston assemblies...

 

[Triz]

Thats kinda what I was thinking but they are both oem pistons I wasn't sure if ford had them weighted the same so they could use the same crank in all.

 

[ms93gt]

If you get an oem stock replacement type piston such as trw,speedpro then you won't have to. Just look at the weights of each.

 

[Triz]

what I have is forged pistons from a 90 5.0 and was going to put them in my 97 explorer block. Would I just need to weigh the piston and if they are the same weight(or within a few grams, not sure how much of a margin of difference you are allowed). then they are ok to swap?

 

[stooges701]

I just rebuilt my engine and switched from stock 92 forged pistons to .30 over speedpro forged pistons and the weight was a pretty big diffrence. I would say it depends on what your wanting to do with this motor, if you going to be spinning high rpms with it I would say get it balanced. I say do the motor once and do it right.

 

[Rick 91GT]

Here do this...

Clean a hyp piston, wieght it with the pin and 1 set of rings.

Clean a frgd piston, weight it with the pin and 1 set of rings.