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Need for piston/ rod assembly weight

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BobHorvath

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I have a need to know the weight of a complete piston/rod assembly for my 65 BJ8. I am having the crank turned, flywheel re-surfaced, damper re-built and I intend to ballance these components. My pistons are still in the block with the head on so I need to know the weight there-of for the ballance.
 
Hi Bob,
There are way too many variables to give you my weights. Different pistons I.E 5 rings vs. 3 rings, oversized pistons, different rod bolts, etc. If you haven't pulled your pistons, how do you know that you won't need new ones, or rings at the very least. I would recommend having yours removed and inspected as well as checking the dimensions of the bores for roundness. Also by resurfacing the flywheel, you may change it's balance in relation to the rest of the engine. There is a mark on the flywheel to orient it to the crank from the factory balancing. If you want the engine balanced, I wouldn't take any shortcuts.
 
BobHorvath said:
I have a need to know the weight of a complete piston/rod assembly for my 65 BJ8. I am having the crank turned, flywheel re-surfaced, damper re-built and I intend to ballance these components. My pistons are still in the block with the head on so I need to know the weight there-of for the ballance.
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I was told many years ago that to balance an engine you have to balance all <span style="font-style: italic">rotating and reciprocating</span> parts.

Having done a couple of engines you must have the pistons all matched for weight. No two pistons are identical in weight so all 6 must be weighed and matched accordingly. No easier way to do this.
Patrick
 
Thanks for the input. I have gone the precise rout on a asupercharged boat engine but this time I was told that I could use an average weight and it could be simulated through a bob weight.
 
In that case, I'd consider going to another machine shop. Doing it once is far less painful and costly than tearing a newly built engine down to re-do something.
 
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