F-Body Lover

whats the difference between both of them in performance? is internal balance more reliable than the externals?

ZONES89RS

iTrader: (25)

Internal is better all around, better for high RPM and easier to find balancers/flexplates/flywheels.

burnrubber

iTrader: (1)

I agree that internal balancing is the way to go. I am not an engine builder, but it makes sense that you want to have any weight/forces balanced as locally as possible. A neutral balanced rotating assembly, with matched weight pistons and rods seems better than using a weighted flywheel or balancer on the end of the crankshaft. Depending on cost, either should work if done properly.

mrdragster1970

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Worth every penny, especially if you eat up your flexplate & spare, you can just grab another one from anywhere.

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F-Body Lover

does external balance means that the flywheel has weights on it ? I got a 383 engine and I just noticed that the flywheel has no weights on it !!

kenSS

iTrader: (1)

External balance has weights on the flywheel and balancer. If u have a steel carnk in it it is internal.

F-Body Lover

but the previous owner told me its external balance !! wait I will take some pictures of the crank and the flywheel and show it to you

F-Body Lover

here are some pictures

burnrubber

iTrader: (1)

Yes, external balancing refers to weighting or drilling the flywheel (or in your case flex plate - for an automatic transmission) and/or harmonic balancer, while internal balancing is done by weighting or drilling the counterweights of the crankshaft. Either one, or a combination of the two can be used to balance a rotating assembly.

Do you know if this engine runs? If it has already been balanced correctly then I would keep everything as it is, otherwise take the engine to a reliable builder or machinist and have them check the balance.

F-Body Lover

the engine was running before in a caprice and then I put it in my camaro but I faced a problem with backfiring due to bended valve's then changed the heads to brodix track 1's and didnt face any problem untill the valve's gave up on me the heads were old and I didnt bother my self with checking anything with them

burnrubber

iTrader: (1)

If the bearings look alright I would probably just keep the block the way it is and figure out the problem with the heads.

kenSS

iTrader: (1)

I don't see any weights on the flex plate and the weights would be on the inside of the balancer towards the timing cover.

Oldsmobility85

iTrader: (1)

External balancers are usually not round two thirds of the balancer usually has a larger diameter. Its kinda hard to explain go on ebay or something and look at a pic of one and you will see what i mean. If someone messed around and put these internal balanced parts on a external balanced crank trust me you would know about it cause it would vibrate. And you would have most likely beat the bearing clearances out of it for sure. Hope this helps.

F-Body Lover

there is no weight in the inside also Im so confused I dont care if its 383 or not I just want to run the engine again in my other car and I had bad time with the starter and large flywheel

burnrubber

iTrader: (1)

Look at the flex plate you have, both sides, as well as the harmonic balancer. If they appear totally symmetrical, the same all the way around, then they should be "neutral." If this is the case, then you should be able to use any "neutral balanced" flex plate or harmonic balancer that fits.

If there is weight added to one side, or more holes drilled in one side, in other words if they are "lopsided" and would not balance from the center on the tip of your finger, then they are being used to balance the engine and you need to keep them installed in the same orientation (direction) on the engine in order for the engine to run smoothly.


Here's an article that discusses engine balancing with some helpful pictures (this is the second page):

http://www.carcraft.com/howto/ccrp_0...l_balance.html

Oldsmobility85

iTrader: (1)

You really dont have much of a choice in flexplate size you either run a Th153 tooth flexplate or a 168. They both take nearly the same size starter. Usually on after market starters the mount head is usually just turned 180*