internal balancing question Guru's inside please
12-11-2003, 01:20 AM
#1
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internal balancing question Guru's inside please Ok, so Im calling around local machine shops asking about pricing for honing, cleaning the block, balancing etc.
Finally I find someone who knows what he's talking about, and he says one price for adding weight on the crank and a lower price for shaving it, to balance it.
My question here is, If im using a stock crank, stock rods, and just lightweight pistons (diamonds 3.905) should he be taking off or adding to it?
Finally I find someone who knows what he's talking about, and he says one price for adding weight on the crank and a lower price for shaving it, to balance it.
My question here is, If im using a stock crank, stock rods, and just lightweight pistons (diamonds 3.905) should he be taking off or adding to it?
12-11-2003, 07:23 AM
#3
Any time you change the weight of an internal piece, you have to rebalance. The counterweights on the crank offset the rotating mass, so if the rotating mass changes weight, you are out of balance.
When you go to lighter components, they usually just drill out the weight, and it costs less. If you go to heavier components, weight must be added. They use heavt metal (mallory) to do this, and it is fairly expensive.
For example, I used a stock crank with Eagle rods and Wiseco pistons, and they have to add $120 worth of mallory to balance everything. Total for balancing was $240.
When you go to lighter components, they usually just drill out the weight, and it costs less. If you go to heavier components, weight must be added. They use heavt metal (mallory) to do this, and it is fairly expensive.
For example, I used a stock crank with Eagle rods and Wiseco pistons, and they have to add $120 worth of mallory to balance everything. Total for balancing was $240.
12-12-2003, 07:51 AM
#5
6600 rpm clutch dump of death Administrator
Just keep in mind, many forged pistons are heavier than the stock piston. A forging is denser than a casting, hence there is more metal in the same area. So, often times forged pistons are heavier. Like everyone said, as long as your reciprocating mass is lighter, you are ok. If it is heavier, you can either lighten the rod and piston, or add weight to the crank.