Re: [AMC-list] AMC factory engine balance

[Frank Swygert <farna@xxxxxxx>]

Yes, we understand how to do it, though I never thought much about the why it's done that way. Tanks for the explanation! I suspended the "other" end of the rod from a wire, all at the same level. 

After reading what Tom found, I find I don't really recall how much I had to remove from the rods. Like Tom, I found the pistons to be within 2 grams (or less) of each other (replacements from NAPA, don't recall brand) and I didn't touch them. I removed some material from the rods, and don't think it was much, but am uncertain exactly how much. I wasn't looking for perfection, just an improvement. Once I was within a gram of the lightest one I stopped.  


--------------
Date: Fri, 19 Feb 2010 18:19:38 -0500 (EST)
From: adh@xxxxxxxxxxxxxxxxx (Sandwich Maker)

" From: Frank Swygert <farna@xxxxxxx>
" 
" 
" I did a "minor balance" on the last 196 I built (didn't
" do it on my stroker though) but don't recall the differences in
" the weights of anything.  I had to remove very little from a few
" pieces to get them all within 2 grams -- just a few hits on the
" bench grinder for a couple rod ends as far as I recall.


" From: tom jennings <tomj@xxxxxxx>
" 
" 
" I static balanced all my rods, and all pistons+pins. 


guys -- when you do the rods, you -do- check big-end and small-end
weights separately, right?  big end weight adds unbalance at crank
speed but small end weight, like the piston, adds unbalance at double
crank speed b/c it stops and starts twice per revolution.

the way my friend with the engine shop does it is with stands with
ball-bearing pivots for the big and small ends.  one sits on the
electronic scale and is zeroed out with the autocal; the other sits at
the same level, so the rod is held -exactly- horizontal.

--
Frank Swygert
Publisher, "American Motors Cars" 
Magazine (AMC)
For all AMC enthusiasts
http://farna.home.att.net/AMC.html
(free download available!)

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