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Engine Specific Info and Questions => IDI Engine => Topic started by: handedyourhat on November 12, 2008, 07:50:40 pm

Title: rotating mass (balance)
Post by: handedyourhat on November 12, 2008, 07:50:40 pm

Can anyone explain to me how does VW balance the rotating internal parts ie, pistons , rods and the crank. I weighed my conn rods and noticed that they are all different weights, I was  :shock:  to see this. So If i get all the rods and pistons at the same weight will this be wrong, does VW balance all three together in a machine ? ( rods , pistons crank ).

Dan

Title: rotating mass (balance)
Post by: stewardc on November 13, 2008, 12:47:44 pm

VW doesn't balance anything - that's why everything is a different weight. That's left up to us powernuts. Find the lightest rod and take all to that weight...the same with the pistons. Then have a speed shop balance the crank. you'll be glad you did.

Title: rotating mass (balance)
Post by: jtanguay on November 13, 2008, 02:26:55 pm

i highly doubt any car company would balance the internal components... and if they do, their cars aren't cheap! it would cost significant time/money to weigh/balance...  clearances are one thing you can't really skimp on though...

Title: rotating mass (balance)
Post by: smutts on November 14, 2008, 01:41:25 pm

Thanks for the heads up! 8)

Title: rotating mass (balance)
Post by: Sprockets on November 15, 2008, 02:15:25 am

Really you should be measuring rods on an 'end to end' basis.  Pistons are nice and simple, just  weigh them with the ring pack, and make them equal to the lightest (or are as far as you want to go......seen some petrol pistons wich barely have enough space for the ring pack!  Granted, they are race motors, just making a point :) )

Google gave me this as the first link, and looks a good setup:

http://www.angelfire.com/ca4/CorvAIRCRAFT/RodBalance.html

-Gavin