My current setup is NA, but in close future I will get a Procharger. So I will change the cam and pistons.
Now my pistons are diamond -5 valve reliefs. If I get Diamond -31 dished, rebalance is required ?? (Crank is Lunati CJ117BN)

 

All rotating assemblies need to be balanced together.. changing out the pistons completely throws off the balance.

 

OMG! Even the old and new pistons have the same weight ?

 

I guess if the old pistons and the new pistons for EACH cylinder have the same EXACT weight... (down to whatever difference is important), then you could get away with it I imagine.

 

Yeah they never have the same weight. My current Flat tops have 396 and -32 dished have 417 weight. Damned!!

 

I just did this. The pistons, rings and pins with retainers if you have floating pins, all need to be wieighed, then the pistons need to be cut down to the original weights. For example if all you old pistons were 420 grams, and your new ones are 421, remove the 1 gram as best as the shop can. Thats there profession so they will know how to do it.

 

So you say 21 grams can be removed? Isn't this unhealthy? I mean there is a reason blower pistons are heavier.

 

I never said 21 grams. I said if the old was 420 grams, and the new 421 remove 1 .

 

lol I tought that was an example. If there is 1-2-3-4-5 grams difference no big deal.

 

No worries.

 

So I will never have a blower Because here there is no engine shop do balance job.

Damn I should be in US. I even can't believe how I built a 383cid for 17.000$, oh sorry 30.000$ (shouldn't forget taxes)

 

DAMN, thats allot of money. I would just get someone to buy it for you and send it across the border. Cant be all that hard?

 

Where are you located? Do you have shipping? Find out what your old and new pistons weigh and have them sent off if need be.

 

Here there is no escape from taxes. Its not about the border. Here 1 gallon gas is 8$ what about that!

Dave, I'm from Turkey. The old ones have 396 weight and new ones 417. Maybe I can find a set of dished pistons of other brand than Diamond that have nearly 396 weight, but I know there isn't.

 

i could be 100% wrong here but,when balancing an engine dont they just make sure all the pistons are the same weight.so if you had 4 that were 421 and 4 that were 420,you would make them all the same.so going from 396 to 421 shoudl not matter.

i could be completely wrong,but what determines 396 was a "correct" weight.i just though as long as they were all the same you were good.

your car look great btw