Engine Balancing?

wardog

R.G.V WARDOG
Jan 19, 2006
564
0
16
ALTON, TX
Im rebuilding my 7mgte engine and with eagle rods and Probe pistons for a 500 rwhp DD . Is it Necessary to balance the assembly? I running into money issues, anybody done some good power with out balancing the rotating assembly? Any input is always appreciated
 

zachm611

Beauty In Disguise
Apr 15, 2006
543
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16
37
new mexico
if you are shooting for power then yes it is necessary and highly recommended.. i say sit on the build for a little bit to save up the money for the balancing.
 

Tanya

Supramania Contributor
Aug 15, 2005
1,851
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42
Naples, FL
It's highly recommended in any situation where you're changing engine internals.

VERY much worth the money.
 

Rennat

5psi...? haha
Dec 6, 2005
2,844
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Tracy, CA
www.myspace.com
my motors revs like it has a lightened flywheel, rev matches like a honda, and when your shifting in "racing" type situations it seems to fall right in the right rpm to match the next gear.

and BTW, i have eagle rods and probe pistons... i vote 100% necessary.
this is also on a stock flywheel too...
 

StiCk3

Member
Apr 25, 2009
155
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16
->IN<-
with brand new parts out of the box it is 100&#37; required to balance the internals unless you want your engine to rattle apart and suffer premature engine failure.
 

suprarich

Guest
Nov 9, 2005
2,187
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ohio
Plenty of people have just installed the new forged parts without balancing and had it work fine. Our crank is some what balanced from the factory. The damper is balanced, and the flywheel/flexplate is balanced. So in theory, if you install a rod/piston combination across all 6 holes that are very close in gram weight, then you will be within a close percentage of being in a passable balance.

You match lighter pistons from the group, to heavy rods from the group, to try to make all 6 rod/piston combinations close to the same gram weight.

Now all that being said, you could get away with not machine balancing your rotating assembly, but why? It is not a high cost to spin balalance the entire assembly. For any higher HP car, I mandate that the entire rotating assembley be high speed spin balanced to under 1 gram accross 3 points of the crank.

To do a high speed spin balance, you need: The finished crank, the damper, the flywheel/flexplate, the flywheel bolts. Also, you will need the weight in grams of: each piston with the pin and rings, Each rod with its bearing installed. You could just give the piston and rod assembly to the machinist to gram scale, but if you don't want to mail all of that stuff, just gram scale it yourself.