Rubber O ring for cranshaft pulleys.
 

Hey everyone:
Thanks to Andre ffrom right here on the forums I was able to get the a/c crankshaft pulleys I need for my 1964 Catalina. My car has 67 a/c pulleys on the water pump, alternator and power steering pump. However, I need to find the large rubber o ring that goes between the pulleys. Does anyone know if they are reproduced, or if any old ones are available. Or maybe a work around with another type of rubber, or??
Thanks.
Mike.

Can you post pics (with arrows pointing to what you're referring to)?

O'ring for pulleys
 

Here is a picture of the parts needed. As you can see there is a large rubber O'ring or rubber cushion between the a/c pulley and the two groove pulley.
Mike.

HMMMMM I've never noticed that before. If you can't find one cut one out of an inner tube.

MIke

Having taken apart hundreds of Pontiac engines. I've never seen a rubber ring except on the balancer. Probably was put there by someone.

Thanks everyone. I am confused to say the least in that the one posting seems to be very certain of what is needed and where it goes.
I will defer to all of the good advice and install it with my own type of rubber. Or none at all.
Thanks again. As always. This forum is the best.
Mike.

Blackcat,

I think you're correct. I've never seen one like that,either.

I've had the ring shown in Mike's pic at least a half dozen times and all were from '67 a/c app crank pulley stacks. It was factory positioned between the supplemental A/C (rear) pulley & the '67 two groove (ac app) crank pulley.

Mike & I have determined there are two different part numbers for the '67 two groove (a/c application) '67 crank pulley. here's what I'm thinking, when one of these versions of '67 two groove crank pulley was bolted to the single groove supplemental pulley, the ring was used. When the other 2 groove a/c app two groove '67 crank pulley was installed the ring was not used.

I still have no idea what the reasoning for its use is. Do know a yard where a few rows of '67 Cats & Bonne's are setting & am going to reload on '67 a/c crank pulleys, so am not out.

I have been sketching out the stackup and using '62 and '66 A/C pulleys as my mental guide, maybe the compression of the o-ring is to solve a perceived vibration problem?

That said, the stack of pulleys, steel spacer and balance weight flanges all need to get sandwiched and torqued to the crank sleeve/flange, so the rubber o-ring can't be so thick that it affect the torque on the six screws.

I am eager to get more info on this cuz it don't make no damn sense to this shadetree wrench.

"O" ring
 

Mike, I've found those "O" rings on every 64 thru 67 V-8 a/c Pontiac I've ever taken apart.
(Even found one on a 68) I don't know their purpose but they get sandwiched between the inner (a/c) pulley and the outer pulley. I only have one at the moment that I need to complete my setup, (from a 66 LeMans 326") but they can be found on any 64-67 a/c Pontiac incl. Tempest, LeMans, GTO etc...
The ring has about the same thickness as 1/4" gas hose and is approx. 5 inches in diameter. It is solid rubber and kind of soft.
Hope this helps, Good luck.
Jim

That photo posted above is from my engine.

It most definitely has been in there since car was built.
Best I can guess is that it was put in there to keep road debris from lodging in there and causing rust out. It seems to have been about 3/8" thick originally (best guess), maybe slightly bigger.

It goes between the AC pulley and the two groove for the alternator/power steering one.

Charles

Found a site online that had a solid write up of 67 firebird AC system. I could not find the part number though. I know I have seen another thread about 6 months ago on here (or on the street forum) about the rubber piece. Obvously I don't have the experiance that these other guys do, but appears that this is a factory part.

http://firstgenfirebird.org/forums/u...08025&page=all

It is listed about 1/6 the way down the page

Poster there states that it was presumably there for vibration dampening.

I just don't believe that was it's purpose.

When I took mine apart, there was quite a bit of crud built up on the outside of the rubber.

Maybe it was a search that i did?

http://forums.maxperformanceinc.com/...ey+rubber+ring

A harmonic balancer (also called crank pulley damper, crankshaft damper, torsional damper, or vibration damper) is a device connected to the crankshaft of an engine to reduce torsional vibration and serves as a pulley for drive belts.
Every time the cylinders fire, torque is imparted to the crankshaft. The crankshaft deflects under this torque, which sets up vibrations when the torque is released. At certain engine speeds the torques imparted by the cylinders are in synch with the vibrations in the crankshaft, which results in a phenomenon called resonance. This resonance causes stress beyond what the crankshaft can withstand, resulting in crankshaft failure.

To prevent this vibration, a harmonic balancer is attached to the front part of the crankshaft. The damper is composed of two elements: a mass and an energy dissipating element. The mass resists the acceleration of the vibration and the energy dissipating (rubber/clutch/fluid) element absorbs the vibrations

Not a member on FGF, but would like to thank Pete on his excellent write-up!!!
Having gone through sourcing under dash duct parts to complete factory a/c setups on two '68 400 Birds, I would have loved to have had that thread at my disposal.

I want to thank old goat 67 for the use of his picture.
I am going to re post the text for that picture which calls out the part numbers for the pulleys.
Correct fan pulley for 67 AC GTO is part # 9786909XJ, 7 1/4"diameter by 2 " deep, 1st Picture.

Correct arrangement for crank pulley's are as shown in second picture rear to front from left to right is first the #9782704 AC Pulley, followed by a large rubber O ring between the pulley's, followed by #9786907 Alternator & Power Steering pulley, followed by the stiffener plate then the vibration damper.

Here are the numbers on the pulleys I got from Andre. The a/c pulley is 9782704. The same as the one for Old Goat 67. However, the two groove pulley number is 9782680 which is different the pulleys from Old Goat 67.
Can I then assume then that my pulleys may not use the o'ring as ol pinion head has suggested?
Sure is strange!!!
Thanks again everyone.
Mike.

You're quite welcome Mike. That's why we post here, isn't it.

It is strange as to why some have it and others do not. Surely it is not really a "vibration" damper element or they would all have it. It just fills the gap between the two pulley units. There is not a reproduction made, is there?

Charles

I have not found a reproduction, and I have looked. I think what I bought from Andre will work, I just want to make sure I do not need that rubber O ring. Hopefully ol pinion head will post again on what he finds.
Thanks again.
Mike.