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Joe Elwell
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119 Posts
Discussion Starter #1
All - I'm rebuilding a 3L V6 I got from a Milano. I located a set of NOS 164S pistons/liners that I will install. Using original crank and rods.

Do I need to rebalance it after this?

Answers, with thoughts on why/why not would really be appreciated.

best,
Joe
 

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Premium Member
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21,697 Posts
Depends on how into it you are. Crank and flywheel I'd say no. But I'd say it's worth getting rod/piston combos checked and balanced. Alfa stuff is generally pretty good from the factory, but rod/piston combos should be balanced as a unit against the others in the engine, and end to end.
Andrew
 

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Joe Elwell
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119 Posts
Discussion Starter #3
Thanks Andrew. But I'm not sure I understand completely. Balancing the rod/piston combos means matching their weights so that all piston/rod combos are identical?
thx
Joe
 

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Registered
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311 Posts
If you are building a race engine and plan on running it to 7500rpm you might want to match piston weights and check rods. For a street engine you can simply reassemble it as is.
 

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Premium Member
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21,697 Posts
Any engine I build, I have Norman Racing match the total weight of the piston/rod combo, so all six are the same. Rods also have an end to end weight that can be checked and optimized. As long as you're at it. But yes, stock engine not going for high rpm, probably fine, especially if it's rods you've used.
Andrew
 

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Joe Elwell
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119 Posts
Discussion Starter #6
Thanks Andrew, for clarifying - that makes sense.

And also Alfistaa for chiming in - I won't likely even take this out on the track, so although it will have quite a bit more power, I don't see running it past stock redline much, if at all. Plenty of music at that speed :).
 

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Richard Jemison
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7,381 Posts
No you do not need to re-balance.
As to engine building regarding "Balancing" the real concern is only the rotating weights Crank/ Rod big ends/flywheel/sometimes the front pulley. Reciprocating parts like pistons can be different weights within 10 grams (Between each piston) and it`s no problen. I try to get them under 2 grams but it`s just being anal.
 

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Joe Elwell
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119 Posts
Discussion Starter #8
No you do not need to re-balance.
As to engine building regarding "Balancing" the real concern is only the rotating weights Crank/ Rod big ends/flywheel/sometimes the front pulley. Reciprocating parts like pistons can be different weights within 10 grams (Between each piston) and it`s no problen. I try to get them under 2 grams but it`s just being anal.
Thanks Richard - I appreciate the info about piston weights as well.
Joe
 
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