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Danglerb's Avatar
 
Join Date: Jan 2007
Location: SoCal
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Need to replace harmonic balancer?

I haven't thought much about the harmonic balancer, but a little casual searching and it looks like they are items that age, with some suggesting replacement when the engine is rebuilt or every 10 years. Its not clear if new units are still available, and mine are 25 years old.

Harmonic balancer, or vibration damper, goes on the front of the crankshaft to absorb the twisting motion of the crank created by some cylinders being in power stroke and some in the compression stroke (over simplified I know). Its usually some kind of "pulley" with a rubber layer and a outer metal "flywheel".

Back in April one of the Rlist guys put together a group buy from ATI to have a batch of super dampers made (race quality, and rebuildible). I just sent ATI an email asking if they might make another batch. I think they were about $500 last time, and made as direct replacements for the 83/91 factory part.
http://www.ati************************/products/dampers/damper_tech.htm

Any opinions or suggestions on this?

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US 83 zinc metallic 5 spd, aka the nice car.
Euro 85 black, 5 spd, the fast rough track car maybe car. SOLD
Euro 84 red, AT, only car in garage in years, my parts car, soon to go last 7 years.
Old 09-05-2007, 11:24 AM
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interesting thought, but a bad dampener might be corrected by balancing with the rest of the reciprocating assembly. Timing marks might be off, but you could get it back in balance......

PM me if you get an answer from ATI----I'd be interested in one for my hybrid----
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Old 09-05-2007, 07:40 PM
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Ask Hammer, his username is 6.0 something on that RL thread, he's the one that arranged the buy from ATI. They should be able to make a low quantity again, they were very pleasant to deal with.

Last I heard there were no more Porsche balancers left. Someone may offer a reman' someday but I would prefer an ATI.

BTW, I have one of the ATIs, it's very nicely made and dimensionally identical to the Porsche.
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Mike S.

79 928 Racer 427ci 32v 640WHP
Old 09-06-2007, 08:23 AM
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Easier for me to talk to my dead grandma than to get a message through to most on Rlist.

I sent an email to ATI, might as well see how that plays out first.

Heat and time harden the rubber inside the damper and if it can't flex it can't damp much. I just have no idea how fast it happens or how to test it.

I don't know if they actually have any counter weight function, or if the 928 is internally balanced or balanced via the flywheel.
__________________
US 83 zinc metallic 5 spd, aka the nice car.
Euro 85 black, 5 spd, the fast rough track car maybe car. SOLD
Euro 84 red, AT, only car in garage in years, my parts car, soon to go last 7 years.

Last edited by Danglerb; 09-06-2007 at 11:43 AM..
Old 09-06-2007, 11:38 AM
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Looks like no need to try for a group order. It might be polite if there are several of us to order about the same time so they can combine the run. I still have a few more questions to ask before I order anything. I'm going to reply back to his email with the possibility of several of us ordering at the same time.

Email from ATI below,

**************
We can do a (1) off which would cost $500 and have a lead time of 6-8 weeks. Thank you.

Ricky Hults
Sales Associate
rhults@atiracing.com
Old 09-11-2007, 08:36 AM
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Follow up from Ricky, min of 10 for a discount, doesn't sound likely.
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US 83 zinc metallic 5 spd, aka the nice car.
Euro 85 black, 5 spd, the fast rough track car maybe car. SOLD
Euro 84 red, AT, only car in garage in years, my parts car, soon to go last 7 years.
Old 09-11-2007, 12:15 PM
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Talked to a few more people, and consensus was no need to change from the original stock damper for a street driven car.
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US 83 zinc metallic 5 spd, aka the nice car.
Euro 85 black, 5 spd, the fast rough track car maybe car. SOLD
Euro 84 red, AT, only car in garage in years, my parts car, soon to go last 7 years.
Old 09-13-2007, 09:17 PM
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They'll do one for $500? That's great! It doesn't get any better than that and I bet delivery will be sooner rather than later, don't waste anyone's time trying to get a group buy, it wont happen.

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Mike S.

79 928 Racer 427ci 32v 640WHP
Old 09-15-2007, 08:52 AM
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