Re: 440 Balancing
[Re: tmef]
#2901952
03/23/21 10:59 AM
03/23/21 10:59 AM
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Joined: Jan 2003
Posts: 10,758 North Dakota
6PakBee
I Live Here
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I Live Here
Joined: Jan 2003
Posts: 10,758
North Dakota
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Any time you deviate from a stock component in the reciprocating assembly that doesn't have the OEM weight, you should rebalance.
"We live in a time when intelligent people are being silenced so that stupid people won't be offended".
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Re: 440 Balancing
[Re: 6PakBee]
#2901972
03/23/21 11:31 AM
03/23/21 11:31 AM
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Joined: Jan 2003
Posts: 13,401 Marion, South Carolina [><]
an8sec70cuda
I Live Here
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I Live Here
Joined: Jan 2003
Posts: 13,401
Marion, South Carolina [><]
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Any time you deviate from a stock component in the reciprocating assembly that doesn't have the OEM weight, you should rebalance.
CHIP '70 hemicuda, 575" Hemi, 727, Dana 60 '69 road runner, 440-6, 18 spline 4 speed, Dana 60 '71 Demon, 340, low gear 904, 8.75 '73 Chrysler New Yorker, 440, 727, 8.75 '90 Chevy 454SS Silverado, 476" BBC, TH400, 14 bolt '06 GMC 2500HD LBZ Duramax
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Re: 440 Balancing
[Re: tmef]
#2902062
03/23/21 02:38 PM
03/23/21 02:38 PM
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Joined: Mar 2011
Posts: 3,101 Michigan
A727Tflite
master
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master
Joined: Mar 2011
Posts: 3,101
Michigan
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My 440 was originally out of a motor home. It is a 1974 with a forged crank. It had six pack rods. I took it .030 and used cast pistons with LY rods. Would you have gotten the rotating assembly balanced? I am thinking of taking it .040 over with forged pistons. Would you have it balanced then? If the current engine doesn’t have any vibration issues then compare the new piston against the old. With a gram scale, assuming the new pistons are heavier, you can match the the new pistons to the old. No need to balance the whole assembly then.
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Re: 440 Balancing
[Re: tmef]
#2902067
03/23/21 02:56 PM
03/23/21 02:56 PM
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Joined: Aug 2003
Posts: 43,303 Bend,OR USA
Cab_Burge
I Win
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I Win
Joined: Aug 2003
Posts: 43,303
Bend,OR USA
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My 440 was originally out of a motor home. It is a 1974 with a forged crank. It had six pack rods. I took it .030 and used cast pistons with LY rods. Would you have gotten the rotating assembly balanced? I am thinking of taking it .040 over with forged pistons. Would you have it balanced then? Are you feeling really lucky or hoping to get lucky Do it correctly once or maybe, probably, have to do it over later I always cost more later to do it over
Mr.Cab Racing and winning with Mopars since 1964. (Old F--t, Huh)
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Re: 440 Balancing
[Re: 1972CudaV21]
#2902106
03/23/21 04:40 PM
03/23/21 04:40 PM
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Joined: Mar 2011
Posts: 3,101 Michigan
A727Tflite
master
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master
Joined: Mar 2011
Posts: 3,101
Michigan
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Can you destroy an engine without balancing? Depends how bad it is out, and long you run it and at what engine speed. I would think most people would not drive it long enough if it vibrated badly. But then again.........
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Re: 440 Balancing
[Re: 1972CudaV21]
#2902147
03/23/21 06:08 PM
03/23/21 06:08 PM
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Joined: Jan 2003
Posts: 6,433 Abilene, Texas
fastmark
master
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master
Joined: Jan 2003
Posts: 6,433
Abilene, Texas
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Can you destroy an engine without balancing? A friend bought a 69 charger 4 speed car that had a cast crank externally motor in it when he bought it. It vibrated. The car had the original neutral balance flywheel. It beat the bearing out of the hub for the pilot bearing and may have damaged the transmission. The rear main leaked as well. Suprisingly, the main bearings looked ok.
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Re: 440 Balancing
[Re: Cab_Burge]
#2902159
03/23/21 07:08 PM
03/23/21 07:08 PM
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Joined: Oct 2005
Posts: 273 Anchorage, Alaska
metallicareload
enthusiast
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enthusiast
Joined: Oct 2005
Posts: 273
Anchorage, Alaska
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My 440 was originally out of a motor home. It is a 1974 with a forged crank. It had six pack rods. I took it .030 and used cast pistons with LY rods. Would you have gotten the rotating assembly balanced? I am thinking of taking it .040 over with forged pistons. Would you have it balanced then? Are you feeling really lucky or hoping to get lucky Do it correctly once or maybe, probably, have to do it over later I always cost more later to do it over I don't know how much balancing would cost where you are, but I've never seen a price so out of line that I wouldn't do it. My 440 was balanced with the damper and flywheel, and it runs incredibly smooth, I thought it was money well spent. If some how the price is outrages or this is an engine that "doesn't need it" I'd at least do what Transman suggests
440, 4-Speed, 3.54 1968, when Dinosaurs ruled the Earth
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Re: 440 Balancing
[Re: metallicareload]
#2902281
03/24/21 08:58 AM
03/24/21 08:58 AM
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Joined: Mar 2006
Posts: 9,882 MI, usa
dvw
master
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master
Joined: Mar 2006
Posts: 9,882
MI, usa
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Some people over balance, add extra bob weight. Some under balance , remove bob weight. The factory tolerance cylinder to cylinder is not spot on. How much can you get away with? Obliviously the factory specs work. Engines run a long time being untouched. Now lets say the new pistons are close or slightly under in weight. Is it a big deal being under balanced, probably not. Where you get into trouble is like a cast crank scenario. The bob weight is far greater than the crank counterweight mass. In this case extra counter weight mass must come from the flex plate, converter, flywheel, balancer. Is balancing a bad thing? No. Is it absolutely necessary when weights are close in a street application? In my opinion, no. Doug
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Re: 440 Balancing
[Re: dvw]
#2902283
03/24/21 09:12 AM
03/24/21 09:12 AM
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Joined: Jan 2003
Posts: 10,758 North Dakota
6PakBee
I Live Here
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I Live Here
Joined: Jan 2003
Posts: 10,758
North Dakota
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What I think you have to keep in mind that the magnitude of any unbalance increase as the square of the speed. Double the speed, four times the force due to unbalance. So if you have an engine that never gets over 4000 rpm, it can tolerate considerably more unbalance than an engine turning 8000 rpm.
"We live in a time when intelligent people are being silenced so that stupid people won't be offended".
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