The procedure usually goes something like this. The pistons are machined
so that they each weigh the same. The rods are machined so that the
small ends will all weigh the same and the big ends will all be the
same. Then a weight is calculated from this and that weight used to
balance the crank. If the rods and pistons have been balanced properly,
there is no problem with them being disassembled.
The pulley is balanced with the crank, but the flywheel is sometimes
done separately, since you might wind up replacing the flywheel at some
time and you wouldn't want to unbalance the whole mess as a consequence.
The pressure plate always gets balanced separately for the same reason.
Stephan Sochoux wrote:
> Hello all,
>
> I'm in the process of doing a complete U20 rebuild and
> i'm currently concerned with what has been done so far
> at the machine shop (screw up on the jackshaft bearing
> install).
>
> I paid to get the engine balanced. What components get
> balanced ? I supplied the flywheel, crankshaft and
> crankshaft pulley. The machinist already had the rods.
> I think he said that he balanced the
> flywheel/crank/pulley assembly. I asked about the
> clutch pressure plate and he said i should get a new
> one, that it doesn't get balanced with the assembly.
> Hmmm..
>
> When I got all the parts back, my new pistons and rods
> were not assembled. Should they have been ? Aren't the
> pistons and rods "married" correctly and balanced with
> the whole thing ?
>
> I need to have an intelligent conversation with him
> but i need to sound like i know what i'm talking
> about...
>
> Any other items i should ask/look for ?
>
> TIA,
>
> Stephan
> '69 2000
--
Gordon Glasgow
http://www.gordon-glasgow.org
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