FE Power Forums
FE Power Forums => FE Technical Forum => Topic started by: kostiuk on November 21, 2019, 08:17:06 PM
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I have a 428 I recently rebuilt and I had it balanced. Now I want to change the dampener. May be a stupid question but is it alright to change it?
Thanks, Kevin K.
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The 428 was originally externally-balanced, I will assume that yours still is. That means the machine shop added or subtracted weight from the balancer and/or flywheel/flexplate. A good shop might be able to match a new balancer to your old one but to be safe you should probably have the entire assembly rebalanced if you get a new balancer. You also might want to talk to your machine shop and see what they are capable of doing and see what they recommend.
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The entire rotating assembly was balanced.
Thanks, Kevin K.
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Your Balancer should be zero so no problem changing it as long as the new is zero. your 428 was externally balanced at the fly wheel and a reputable shop would make minor tweeking adjustments internally. You should ask your shop how they did it.
The Super CJ 428 had the hatchet weight behind the balancer to compensate for the extra weight of the LeMans rods
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Your Balancer should be zero so no problem changing it as long as the new is zero. your 428 was externally balanced at the fly wheel and a reputable shop would make minor tweeking adjustments internally. You should ask your shop how they did it.
The Super CJ 428 had the hatchet weight behind the balancer to compensate for the extra weight of the LeMans rods
Ranch, the machine shop that balanced my engine did remove weight from the balancer. Maybe most shops don't do it that way but I would still check with the shop as you suggested.
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If your machine shop took weight from the balancer, the only reason would be to zero balance it. All FE harmonic balancers are zero balanced; the external balancing on a 428 is done at the flywheel, or with the 428SCJ crank sleeve, not the balancer. Changing FE harmonic balancers on an already assembled engine is no problem.
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The statement made previously, that the damper unit on the FE 428 is of neutral imbalance sum is correct, and if the shop performed the balancing effort executed such properly, then so it remained, with only perhaps the corrections required to establish such in a more accurate value. The problem is, you will have to establish this, as if any "corrections" have been made to the damper, lazy balancing executions will at times utilize, improperly, this available surface to permit finishing the job with greater expediency. ;)
Scott.
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Thanks for all the help. The shop balanced the flywheel and the crank, I know for sure but I don't know about the balancer. I'm going to stop and check with them this afternoon. I would be surprised if I could not change it but stranger things have happened.
Kevin K.
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Your answer is three posts up. Go with Jay's advice and you'll be fine.
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If your machine shop took weight from the balancer, the only reason would be to zero balance it.
You are assuming that they knew what they were doing! I'm not arguing that it shouldn't be neutrally balanced. My point is you shouldn't assume that it was done that way; double check and verify first! I was not happy with the way my engine was balanced; they took a huge chunk out of the balancer and I can guarantee it is not zero-balanced. I'll see if I can get photos if it would help. Play it safe and make sure your machine shop did it right by talking to them first.
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Jay, here is a photo of my balancer; note the approximately 1-1/2" chunk missing. I don't recall for sure but there may be other lightening holes that aren't visible. The engine was balanced around 1983. It is a 427 sideoiler that was being stroked with a 428 crank and Lemans rods were being added at the same time. The use of the "hatchet" wasn't common knowledge at the time, so I didn't know I should try to locate one and neither did the machine shop. Imagine trying to find one in the pre-internet 80's... In the end, it was balanced and I haven't had any problems since but it isn't pretty and I can't just replace the balancer without matching the offset balance weight.
(https://i.imgur.com/Dh199pdl.jpg)
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I'm so arrogant. I get that feeling that, at my age, I've seen everything. And then there's this.
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So ths motor is now internally balanced and I can put any balancer I want on as long as it's zero. It's like I thought it should be but best to be safe. Thanks guys.
Kevin K.
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Jay, here is a photo of my balancer; note the approximately 1-1/2" chunk missing. I don't recall for sure but there may be other lightening holes that aren't visible. The engine was balanced around 1983. It is a 427 sideoiler that was being stroked with a 428 crank and Lemans rods were being added at the same time. The use of the "hatchet" wasn't common knowledge at the time, so I didn't know I should try to locate one and neither did the machine shop. Imagine trying to find one in the pre-internet 80's... In the end, it was balanced and I haven't had any problems since but it isn't pretty and I can't just replace the balancer without matching the offset balance weight.
(https://i.imgur.com/Dh199pdl.jpg)
The work of some machine shops continues to amaze me... :(
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Cannot see for certain, but that does not look like a terrible fix - especially considering the era in which it was done. If I were needing to replace it I would bring that one and my chosen new piece to a machine shop and have it match balanced. Its not like its a frequent service item.
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Cannot see for certain, but that does not look like a terrible fix - especially considering the era in which it was done. If I were needing to replace it I would bring that one and my chosen new piece to a machine shop and have it match balanced. Its not like its a frequent service item.
Thanks Barry. I would definitely have a new balancer match balanced if I ever get one. Another problem is the chunk that was removed contained the high end of the timing marks. I can set initial timing but checking at 3000 rpm isn't possible.
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I've had 428 cranks balanced with LeMans rods, back in the early 1980s, and nothing was required to be done to the harmonic balancer. Weight was added to the crank counterweights to compensate for the heavier rods. I still don't like cutting the balancer as a solution.
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Cannot see for certain, but that does not look like a terrible fix - especially considering the era in which it was done. If I were needing to replace it I would bring that one and my chosen new piece to a machine shop and have it match balanced. Its not like its a frequent service item.
Thanks Barry. I would definitely have a new balancer match balanced if I ever get one. Another problem is the chunk that was removed contained the high end of the timing marks. I can set initial timing but checking at 3000 rpm isn't possible.
Use a piece of "timing mark tape" and time it on a different cylinder than #1
I do this sort of thing all the time. With a dial back light only TDC is needed for any given cylinder.
Tape; https://www.summitracing.com/parts/msd-8985?seid=srese1&gclid=EAIaIQobChMIz4LHx5qD5gIVXB6tBh0uUgDEEAQYBCABEgI0HfD_BwE
Use a pi