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 Blocks / Cranks/ Rods and Pistons
 455 balancing - stock cast vs forged +30
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chris60s
Tribal Scout

USA
14 Posts

Posted - 03 Jun 2016 :  2:07:12 PM  Show Profile  Reply with Quote
I may have to get block bored. I weighed stock piston/rod assembly (1740g) and a forged piston (STD not +30) with stock pin/rod (1710g) - both without rings. Maybe a +30 piston is a bit heavier - pins are same thickness (.191")but I don't know if different weight. Is always good to get balanced, but if changing from stock standard pistons to SpeedPro L2359NF30 pistons, will the balance be off much from original?

I know nothing about balancing, but think I read somewhere that stock engines may be within 50g. For this 5000 rpm 455, 50g is about 1.7% of total weight, though guess it matters where the piston difference is placed.

Edited by - chris60s on 03 Jun 2016 4:26:01 PM

Tub
Sitting Bull

172 Posts

Posted - 03 Jun 2016 :  5:18:37 PM  Show Profile  Reply with Quote
I am not recommending that you do it.

But, with that said, I built several low buck 455 bracket engines, with the old L2359F30 TRW pistons, stock cast rods, and a reground crank kit, from a wholesale warehouse. Never had one balanced. Made a lot of drag strip passes, and never lost a shortblock. Shifted at 5000rpm, with a rev limiter set on 5500rpm.

I recommend RPM 5140 forged rods and balancing, IF your budget can stand it. But, that adds about $500 or so to the cost.

http://www.racingpartsmaximum.com/sae5140stockrod-2.html

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chris60s
Tribal Scout

USA
14 Posts

Posted - 03 Jun 2016 :  10:16:14 PM  Show Profile  Reply with Quote
I'll get it balanced if I get the block done. I guess the factory spec I saw was either not true or not good enough. A couple hundred more (even without new rods) would be a good investment for what it does.

Edited by - chris60s on 03 Jun 2016 10:17:11 PM
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chris60s
Tribal Scout

USA
14 Posts

Posted - 06 Jun 2016 :  2:24:08 PM  Show Profile  Reply with Quote
I'm going to get this engine rebuilt/balanced, but piston/pin/rod weight is going to be close.

Ebay/FalconGlobal shows specs for the 2359s - std is 584g, +30 is 597g, both +/- 10g. The rod I weighed with the std 2359 had polished sides, while the stock piston/rod assy didn't (a couple grams?). The std 2359 I have must be heavy (584+9) so total difference may only be 8 grams - a balancer's site said factory may be 4-8g difference for piston/pin assy. Balancing better than factory is good to do, but this may account how you got away without it when using L2359F30s.

When I get back there, I'll weigh all 8 piston assys - just curious... a lot of guys raced factory cars on streets back in the day - never thought about engine balance.
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