Author Topic: 1956 Harmonic Balancer question  (Read 166 times)

Offline Lexi

1956 Harmonic Balancer question
« on: March 07, 2019, 10:05:49 PM »
The 1956 MPL lists two different part numbers for harmonic balancers (with pulleys) for cars with and without AC. I suspect the difference is only with the pulley, (3 grooves for AC, 2 grooves without). I have compared harmonic balancers removed from both an and AC as well as a non-AC car and they looked the same to me. They also each have the same number stamped on them; 1461795. Am I correct to assume that the harmonic balancer for both AC and non-AC 1956 Cadillacs are the same and interchangeable? Only the crank pulleys would be different. Thanks, Clay/Lexi

Offline caddyguy

Re: 1956 Harmonic Balancer question
« Reply #1 on: March 08, 2019, 07:19:56 AM »
I would check the weights of each. If they're the same as is the rest of the info provided, then you are correct. G

Offline Lexi

Re: 1956 Harmonic Balancer question
« Reply #2 on: March 08, 2019, 11:53:56 AM »
Thanks Caddyguy! Why did I not think of that? Aside from a visual inspection, is it possible to test a harmonic balancer prior to installation? Would all mid-century Cadillac harmonic balancers be calibrated using a nominal crankshaft spec OR was there some tweaking on the assembly line to match each damper to each crankshaft? I am in the midst of an engine rebuild and I want to make sure I got the best unit on my 365 when done. Thanks again, Clay/Lexi
« Last Edit: March 08, 2019, 09:07:18 PM by Lexi »

Offline JAG56Cad

Re: 1956 Harmonic Balancer question
« Reply #3 on: March 09, 2019, 08:26:11 AM »

Going from memory both are the same but since I'm on a relax vacation my brain cells maybe impacted by the alcohol level.   ;D

The only differences would be the pulley for A/C versus non A/C. I need to checked my spare one when I get home although not ready yet.  ;)
Jose Gomez
CLC Member #23082

Offline caddyguy

Re: 1956 Harmonic Balancer question
« Reply #4 on: March 09, 2019, 10:04:18 AM »
Balancers are not set up per crankshaft, they are made for each designated engine model. I replaced a broken balancer on my Dads 79 continental many years ago with replacement from Ford. Never had a problem. Unless your engine is going to be blueprinted and have all parts sized, measured, calibrated, and independently balanced all moving parts, I would not worry about it. G

Offline Lexi

Re: 1956 Harmonic Balancer question
« Reply #5 on: March 09, 2019, 10:08:04 AM »
Yes, this all makes sense. Thank you Caddyguy and Jose for your comments and assistance. Clay

Offline Lexi

Re: 1956 Harmonic Balancer question
« Reply #6 on: March 17, 2019, 12:33:33 AM »
As Caddyguy suggested I weighed three 1956 Cadillac Harmonic Halancers (HB). Two of them were removed from AC loaded cars and one from a non-AC car. I used an industrial Ohaus solution balance which is capable of weighing loads up to 20 kilos (44 lbs) to within 1 gram accuracy or less. All pulleys are stamped with the number "1461795". This does not correspond to the MPL parts number. Further, that the HB removed from the double pulley crank had another mark stamped on it's surface, "D2". The other pair which came from cars with a triple pulley (AC loaded), had the markings "D1" and "D3" respectively. I do not know what these marks mean, (perhaps casting #s of some sort?). Here are the HB weight results", (minus pulleys):

HB from double pulley: 2462 grams
HB --from triple pulley: 2442 grams
HB --from triple pulley: 2443 grams

Note how the pair of HBs removed from AC cars with a triple crankshaft pulley are within a gram of weight of each other. Given their age and varied driving conditions (and wear/rust) they must have been exposed to, they are more or less the same. The HB from the non-AC car was 20 grams heavier. That is the equivalent of 3 quarters plus a penny of US currency, in weight. All 3 HBs are drilled in one spot, apparently to remove weight for balance at the factory I presume. Using a machinist's depth gauge 2 of the HBs cast iron were drilled to the same depth, but the 2443 gram unit was significantly deeper.

I tanked all of these units so grease and dirt were not issues with weighing but some of the paint remnants on them varied as probably was the degree of normal wear such as rust and pitting on some parts, as well as a slight rubber loss noted in 2, inside the circular "seam" near the main shaft bore area.

Not sure what we can conclude as the sample tested is too small. Is a 20 gram weight differential significant with a spinning crankshaft? The fact that the pair from AC loaded cars were basically identical in weight is interesting even if only coincidental. Think I got a couple more lying around and I may check them time permitting. Posted as food for thought for those interested. Clay/Lexi
« Last Edit: March 17, 2019, 10:35:16 AM by Lexi »