Harmonic Balancer dimensions

[Fire1]

Hi I'm about to buy a new harmonic balancer for my 1982 Cherokee 360. The only one available in Australia is made by Powerbond (Dayco) and is a back order item. The dimensions are listed as:

Nose OD: 2.0"
Crank Bore: 1.358"
Overall Width: 3.228"
Pulley Diameter: 6.732"

If anyone has an old one lying around that they could put a set of vernier calipers over it would be greatly appreciated.

[Stuka]

You could also buy one here in the states. I know the shipping will be more, but BJ's does ship internationally:

https://bjsoffroad.com/harmonic-balancer-amc-360-v8/

[Fire1]

Yeah that’s an option but shipping through BJ’s has become very expensive, their cheapest shipping option was over $200US. Summit Racing is half that and they offer the same Powerbond harmonic balancer PB1483N $106US I can buy in Australia for $156AUD. My concern buying the Powerbond part is 2 of the 3 reviews on Summit mentioned the bore was smaller and the other one said it was a perfect fit hence my request for dimensions.

[Stuka]

Yeah that’s an option but shipping through BJ’s has become very expensive, their cheapest shipping option was over $200US. Summit Racing is half that and they offer the same Powerbond harmonic balancer PB1483N $106US I can buy in Australia for $156AUD. My concern buying the Powerbond part is 2 of the 3 reviews on Summit mentioned the bore was smaller and the other one said it was a perfect fit hence my request for dimensions.

Ouch, that is really costly. Even $100 for shipping is crazy. I know its heavy, but its physically quite small.

My guess there is that AMC V8's are externally balanced. The harmonic balancer is different for every AMC V8. So you can use a 304 balancer on a 360, or a 390 balancer on a 401, etc.

Could be the wrong balancer was shipped to those two, or they bought that one for a 304 or the like. Its tough to know. And sadly, its a pretty expensive gamble for you.

[Fire1]

Thanks for the reply Stuka hopefully someone comes up with the dimensions.

[letank]

It is a tough one, I have done the front seal on 3 different 360 and to my surprise only one was an easy removal/installation using the appropriate tools. On the 74 , being the 2nd owner since 1983 with 78K, it was very tight, but the installation tool did the job. On the 85, no tool was really needed, not too sure of its past as I bought it with 190Kmiles. I did an 86 with low miles of 138Kmiles, and it was almost impossible to install the HB, I was ready to stick the HB in the oven for 10hrs...

I guess an item to put on the to buy list for the next junkyard trip... but no more FSJs in junkyards.

I had to put a repair sleeve on both 74 and 85 as there was a groove on the HB

BadgrooveCrankSleeveFSJ.jpg

What happened to your OE HB?

[Fire1]

Thanks for the reply letank. The hb on my Cherokee is fine but it has to come off to replace the distributor cam gear (the po installed a Chinese HEI distriburor) and i thought it was a best practice to replace it as the Cherokee has done 140,000km. I guess i could take a chance on the original being ok but as I’m remote (Australia) parts have to be sourced from the U.S.

[Fire1]

I noticed the Felpro gasket set I bought has a wear sleeve to address the potential of a groove problem.

[tgreese]

Regarding the HB, I believe the only issues you can have are wear on the sealing surface (see letank's pic above) and deterioration of the plastic dampening layer between the inside and outside layers of the HB. Here in the USA, there are businesses that will replace the plastic layer in your existing HB, thereby rebuilding it.

There should be shops that provide this service in Oz. As long as they retain the original balance of the HB, and keep the inner and outer alignment of the HB parts after restoration, the restored original HB will be fine. Not rocket surgery.

If the seal surface is too worn to use, you can buy a kit with a sleeve and oversized seal that restores the original oil seal effectiveness (ref letank's post above).

[seventynine]

Why do you need to replace the HB? I’ve installed sleeves to to overcome the groove at the seal to stop oil leaks. Easy to do.

But since AMC V8s are externally balanced…I think you would have to have a new one balanced for your engine? Not sure how you would do that without the engine at a machine shop.

Are you rebuilding this one?

[Fire1]

Why do you need to replace the HB? I’ve installed sleeves to to overcome the groove at the seal to stop oil leaks. Easy to do.

But since AMC V8s are externally balanced…I think you would have to have a new one balanced for your engine? Not sure how you would do that without the engine at a machine shop.

Are you rebuilding this one?

I'm not rebuilding the engine just taking the timing cover off to replace the stripped cam gear. As I'm in Australia and a long way from parts suppliers I was getting all the parts together that i thought i might need: MSD cam and distributor gear, gaskets, harmonic balancer and seal. After reading yours and others comments I will take a chance on the HB being ok.

[tgreese]

...
But since AMC V8s are externally balanced…I think you would have to have a new one balanced for your engine? Not sure how you would do that without the engine at a machine shop.
..

The gist of this - the HB is a commodity part that is built with a weight and damping specific to all 360 engines, but not to a specific 360 engine. Same with the 360 flywheel or flexplate. When you replace them, you bolt on the right part, but you don't need any additional correction or calibration if you have the right part.

A machine shop can balance an engine at rebuild time - not the same thing.