My machine shop wants $150 to balance my engine when he rebuilds my 350. The 350 is being converted into a 383 during the rebuild process. Is it worth the extra money? What are the advantages of having my engine balanced? Better idle or longer engine life or both? Any other benefits of having an engine balanced?

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Flynt
1980 Camaro Z28

[This message has been edited by Flynt (edited January 28, 2005).]

GM does a mighty fine job of balancing the engine.
Not just static balancing but also dynamic balancing.

Unless you change cranks, or rods or pistons of significantly different weights, A normal rebuild won't need rebalanced.

I would have thought the way GM throws engines together on an assembly line that their tolrences would leave something to be desired, including weights of componets. Would they take the time to weigh each rod and piston, remove casting flash to balance weights etc...
What advantages is your machinest telling you?

Certainly, IMHO,it will run smoother, should last longer (bearing wear), be able to stay together better at a higher RPM, rev up quicker, have less vibiration and harmonics.

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70 Camaro Z/28 with 461cu.in. BBC & OD Auto, 3.31 12 bolt posi.

It won't idle any smoother, but will have less wear and less stress on the parts at high RPMs. If you plan to spin it past 5500, balance, if not, you'll probably never notice the difference.

Some technical info on blancing:

http://victorylibrary.com/mopar/crank-bal-c.htm#newest

One man's opinion:

http://www.babcox.com/editorial/ar/eb10330.htm

I say balance it. I'd pay to have one done if it had 100 hp or 1000 hp and everything in between. GM apparently doesn't do THAT good a job when they assemble either.

The GM crank and rods that I REUSED and of course the flywheel, pistons, harmonic damper, and the crank pulley were used to balance my engine. I could see on all of these hard parts where material was removed to get a 100% vibration free operation.

You can expect (with a calculator) better fuel economy, longer engine life, and the ability of the engine to climb in RPM's quicker. I'd say it's WELL worth MY money.

If they are rebuilding your engine that was an assembled longblock and your new pistons are within 25 grams of the old ones, no worries for your average rebuild. Mix up a few different rods, an exchange crank that could be a 305 crank, and new pistons that are significantly heavier (slight possibility) or significantly lighter (quite possible) then your money will be well spent. Nothing more frustrating than an engine that vibrates between 2000 and 3000 because of an imbalance.

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Custom Auto, your source for quality machine work, cores and new parts at competetive pricing right here in British Columbia 1-888-563-4050
A Canadian, EH? (with a 10 second street car)

Would you buy tires and not pay the extra money to have them balanced? Balancing new tires is almost a thoughtless upsale these days and a tire that is only .50 oz out of balance can ruin your driving experiance. Do you want your new engine to ruin your driving experiance?

Thanks guys for your thoughts and advice about balancing an engine.

I should have added that this 350 is being turned into a 383 during the rebuild process.

The machine shop owner said a balanced engine should have less wear on the bearings and might have a smoother idle. He also told me most people do not balance a "daily driver" engine. He normally balances only high performance/racing engines.

I just don't want to spend $150.00 and get no performance benefit for my money.

Thanks,

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Flynt
1980 Camaro Z28

When building a 383 you absolutely MUST balance as none of the aftermarket 383 cranks are balanced when purchaced separately since they have no idea of what rods and pistons you are using.
Even if you are using an old 400 crank the balance is different because your pistons will be lighter than stock 400 pistons.
Spend the $150

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Custom Auto, your source for quality machine work, cores and new parts at competetive pricing right here in British Columbia 1-888-563-4050
A Canadian, EH? (with a 10 second street car)

I've posted this before about my unbalanced old junk 301 motor that was made out of, well, junk parts except for the pistons AND I bet the cylinders had at least .010" clearance on them!!!!

It had at least three harmonics that it used to pass through as it went to above 7,000 rpm!! I could tell my rpm's by the way the car/motor vibrated/sounded!!!!

AND it liked to throw a damper or three driving down the road running like 55 to 60 mph!!

Yes, balance it!!

Been there, done that!!! BUT I loved that little old, short-stroke, junk bugger b/c IT would wrap up like there was no tomorrow!! I would wrap her up until the points would bounce, back off of her AND hit her again until she was above 7,000!!!

pdq67