Harmonic Balance Questions

Steve Powell

Registered User
I need a quick schooling on Balancers and crank pulleys with regards to the balancing of both. I understand that Ford balanced the harmonic and pulley as an assembly. If you install a BJH harmonic balance can you reattach the stock pulley? What is the balance on the underdrive pulley? What is "zero balance"?

Steve
 
Neutral balance is exactly that, think of a car wheel after its been ballanced. The factory pulley is balanced as a unit with the factory harmonic ballancer. Good quality machined Underdrive pulleys should be neutral balanced by nature but who knows im sure not many people have ever checked. To use the BJH with the factory pulley it should be rebalanced. I just went and used underdrive pulleys, and then had new problems like overheating and undercharging.
 
When I installed my bhj I had balance checked on my crank pulley separately and it was fine. However ford did it is beyond me, but my opinion each part seemed to have been balance individually, maybe then they went back and balanced as an assembly just to make sure it ran as smooth as possible.

Chris
 
all 9 of my supercoupes have bhj balancers on them, i slapped the stock crank pulley back on and never had an issue with any of them, no vibes either and i have solid motors mounts
 
Thanks for the info guys. I installed a BJH balancer and underdrives, but due to cooling issues with the MP FMIC, I have to go back to stock pulleys. I want to put the stock pulley back on the BJH, but just want to be sure that I won't have any vibration issues. Sound like "decipha" doesn't have any problems. I noticed there is a small balance weight attached to the inside of the stock pulley.

:eek:
 
I seriously doubt that the underdrive pulleys are making it run hot.

David

I have seen it but only with a cooling system that was already stressed. With the water pump spinning more slowly it could cause some issues at idle with an already weak system.
 
I have seen it but only with a cooling system that was already stressed. With the water pump spinning more slowly it could cause some issues at idle with an already weak system.

Radiator cooling capacity and air flow through the radiator are usually much bigger factors than coolant flow rate. I've got underdrive pulleys on my 91 SC and didn't have any cooling problems for the entire 2850 miles driven during the Hot Rod Power Tour last month. Temps were usually in the 180s even idling in summer traffic for extended periods.

David

PS: I think every SC needs a Griffin aluminum radiator.
 
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