We actually did a thread on this several months back. I described to a
certain extent how the machinist balanced my pistons and rods, and also
did a 'dynamic' balance of my crank/harmonic-balancer/flywheel. There is
more to balancing the pistons and rods, than just making sure they all
weigh the same. When they weighed and balanced the rods, they used a
'knife edge' to support the small end, and placed the big end on a
scale. The rod was held at a specific angle when this was done. I can't
remember if it was exactly horizontal, or if it was at some specific
angle (i.e. 20 degrees) from horizontal.
Balancing does make the engine run smoother, and less vibration means
less wear and tear on the crank, and bearings, giving you better engine
life.
Bryan Vandiver (59-bugeye/1275)
San Jose, CA
"Elliott, Patrick" wrote:
>
> Balancing in this case would mean ensuring that each piston con rod pair
> weighed close to the same.
> you weigh all the individual pieces then put the heaviest piston with the
> lightest connecting rod. or whatever combination would result in the closest
> matching of weights. depending on how anal you what to be, you could even
> shave off the casting marks, polish, and shot peen all of the pieces before
> hand. Then fine tune the weights by dimple drilling out extra mass.
>
> Would you notice a difference? maybe. couldn't hurt if you've got the time
> and scales to do it.
>
> -----Original Message-----
> From: Frank Clarici [mailto:spritenut@Exit109.com]
> Sent: Tuesday, January 16, 2001 5:49 PM
> To: Brad Fornal
> Cc: Spridgets List
> Subject: Re: Piston Balancing
>
> Brad Fornal wrote:
>
> > I have a set of triple beams and wondering if anything would be gained
> > by balancing the pistons and rods.
>
> Brad, I may be way off here, but the 1275 has offset con rods,
> I don't think you can balance them. Well I'm sure they can be balanced
> but being offset would require about 8oz of weight added to the other
> side of the rod.
>
> Now having the crank/flywheel balanced is something that is worth the
> cost.
>
> Stick me back in your address book.
> --
>
> Frank Clarici
> Toms River, NJ
> Too Many Sprites Again
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