Harmonic Balancer

[BDAZ1CNB]

I feel stupid asking this question but how do I know if my harmonic balancer is externally or internally balanced? It's a 1974 400 punched out to a 406. The balancer and pulleys are off of a 1970 383 though. I'd like to order one and have it here and ready to install when I take the old one off. Any help would be appreciated. Thanks in advance.

 

[91r/t]

Check this page out. It should help. The problem is you need to know if the crank is internally balanced or externally. The balancer is matched the the type of crankshaft used. The harmonic from a 70 383 is most likely for a forged crank , so that will not be able to be used with your setup if it has an externally balanced crankshaft.

http://www.440source.com/dampers.htm

 

[zyzzyx]

O.K., so I have a stupid question! If someone has been in an engine changing whatever parts inside
and they drop off the rotating assembly with a balancer at the machine shop to balance it, It can be
balanced no matter which balancer they use. Now, the factory used different balancers for say,
Six Pack engines, so we know if the engine has never been apart, then that engine is balanced
either internally or externally. Am I right ? Thanks!

 

[BDAZ1CNB]

Check this page out. It should help. The problem is you need to know if the crank is internally balanced or externally. The balancer is matched the the type of crankshaft used. The harmonic from a 70 383 is most likely for a forged crank , so that will not be able to be used with your setup if it has an externally balanced crankshaft.

http://www.440source.com/dampers.htm

 

[BDAZ1CNB]

Thank you for your help,this will definitely get me where I need to be.

 

[66Satellite47]

A '74 400 will be a cast crank externally balanced crank motor. If it got modified with an earlier 383 steel crank, all should be good. Why would you need a new balancer? What else is going on?

 

[BDAZ1CNB]

A '74 400 will be a cast crank externally balanced crank motor. If it got modified with an earlier 383 steel crank, all should be good. Why would you need a new balancer? What else is going on?

 

[BDAZ1CNB]

It is making a clunking noise at the balancer and I was told they push the rubber out and start making that noise?

 

[wyrmrider]

clunking noise could be our thrust bearings
anything move back and forth?

 

[BDAZ1CNB]

clunking noise could be our thrust bearings
anything move back and forth?

It actually did it on the first engine and it's the only thing that both engines had in common. It has to be the problem.

 

[Daves69]

Mark the damper inner and outer so you can visually see any slip...……...

Here's a 440 automatic trans crank with a worn out thrust...…….

 

[moparmarks]

Here is the 400 cast crank balancer.
400 4-spd cars and trucks got a forged crank and a different balancer.
Yes a machinist could have re-balanced any crank, balancer combo.
What crank is in the motor?

 

[BDAZ1CNB]

Here is the 400 cast crank balancer.
400 4-spd cars and trucks got a forged crank and a different balancer.
Yes a machinist could have re-balanced any crank, balancer combo.
What crank is in the motor?

View attachment 861849

I am not sure,I just need to order a new one. I just don't know the best one to get?

 

[RebelRider]

Can anyone tell me the size bolts I need to I remove the balancer? I’m talking about the 3 that go through the puller.

 

[33 IMP]

If you don't have an obvious offset weight on your balancer, and you still have fillings in your teeth, your engine most likely got a steel, internally balanced crank when it was "punched out".
Assuming your car is a tf, look for a cutout on the flex plate, or a weight added to the torque converter. If you don't see one, it is internally balanced, and you want a balancer for a steel crank 383. I would look for one with a sfi rating, somewhat of an assurance of quality.
I am pretty sure the bolts you need for the puller will be 3/8 coarse, an inch longer than your puller flanges are thick. ( could be 5/16 though, pull a bolt from your crank pulley to be sure).

 

[RebelRider]

If you don't have an obvious offset weight on your balancer, and you still have fillings in your teeth, your engine most likely got a steel, internally balanced crank when it was "punched out".
Assuming your car is a tf, look for a cutout on the flex plate, or a weight added to the torque converter. If you don't see one, it is internally balanced, and you want a balancer for a steel crank 383. I would look for one with a sfi rating, somewhat of an assurance of quality.
I am pretty sure the bolts you need for the puller will be 3/8 coarse, an inch longer than your puller flanges are thick. ( could be 5/16 though, pull a bolt from your crank pulley to be sure).

Thanks

 

[33 IMP]

@RebelRider LOTS of info about the stock dampers at 440 source .com/dampers. Could be a good source for purchase too. Call their tech line?
And you also need to know if you have a uniform pulley bolt pattern, or the earlier one with one offset bolt, out of the six.
383 pulleys would be with the offset, your 400 could be either.