Re: [T3] Crank/Rod Balancing

["Jim Adney" <jadney@vwtype3.org>]

On 7 Mar 2002, at 21:57, Justin C. Earl wrote:

> I notice on Nate's website, he "static balances" his motors by weighing each rod
> and piston and by removing a little material from the 3 heavier ones and getting
> them all the same weight, "static balances them.
> 
> Is this sufficient? Or do I need to get a machine shop to balance my stuff?
> 
> And how do I go about this? Do I mount the rods of the crank and take just
> that assembly in? Are the rods done separately from the crank?

I often do my own pistons since it only requires a good scale and an ordinary 
lathe. You just remove metal from the balancing knobs under the skirt. I try 
to get mine to within 0.1gm.  

Rods should be done "end-for-end" which means that you get all the small 
ends to weigh the same and all the big ends to weigh the same. I think 
anyone could do this themselves with a belt sander and a specially adapted 
scale.  

rods and pistons are probably the least important things to do, however. The 
really heavy stuff comes first: crank and flywheel.  

I have always sent my stuff to Berg, however, because the rotating stuff 
takes special equipment to do correctly and they just charge a flat rate for 
the whole type 3 works: crank, flywheel, rods, fan, pulley, pressure plate, 
clutch disk, & pistons. They do the rotating gear dynamically, which is 
MUCH better than static. I think static is the only thing possible for rods and 
pistons, however. Sometimes I hold back the pistons and do them myself 
just because they are pretty fragile and I don't want to take a chance on 
getting them damaged in shipping.  

If you're not clear on what they do, you should buy their catalog. It is an 
education in itself and may open your eyes as to what is possible.  

-
Jim Adney
jadney@vwtype3.org
Madison, WI 53711-3054
USA

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