engine balance
Former Vendor
Joined: Nov 2006
Posts: 2,482
Likes: 3
From: Carmichael ca
Assuming the rods are in their original packaging, then I don't see how any balancing was ever done. Generally during balancing there will be some metal removed from the big and or small end of the rods.
Safety Car
Joined: Apr 2005
Posts: 3,624
Likes: 431
From: Dale City VA
Run of mill performance parts usually come in matched sets to with in 4 grams from the mfgr. 1st quality stuff comes within 2 grams from the mfgr.
It depends but most performance shops try to get the parts used in a racing engine with in at least 2 grams (on all rotating parts).... Some shops go well beyond that to .5 a gram.... Some shops figure 4 grams is close enough on lesser engines.
A lot of shops also cut corners by taking the weights listed on the "balance card" that comes with the rods from the mfgr when figuring the bob weight. They SHOULD actually weigh them to verify - but like I said, everybody has their own idea of what "good enough" actually is....
Will
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Safety Car
Joined: Apr 2005
Posts: 3,624
Likes: 431
From: Dale City VA
To calculate your bob weight you need 2 things from the connecting rod. 1. total rod weight and 2. the "big end" weight to calculate the "recripricating"... to get that you have to put the rod on a special fixture, kinda hard to do in the bag.
Will
Le Mans Master
Joined: Oct 2003
Posts: 6,130
Likes: 2
From: seattle WA
Many years ago, but my builder not only weighed them all, but measured each one too. Can't rem,ember how many he rejected, but it surprised me, not because of weight but because of dimensions.
Melting Slicks
Joined: Feb 2008
Posts: 3,286
Likes: 6
From: Palm Beach
If each rod was not weighed, it was not done correctly. That could have been done before they were packaged. If that is the case, there would be a weight card.
Last edited by MK 82; Sep 17, 2009 at 06:18 PM.