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340 Harmonic Balancer Question

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#1 ·
Hey guys,

I'm taking some of my 340 apart to replace some things and detail the engine. I'm installing a new balancer and the one that I took off has this funny pieces on it that sit's up against the timing cover with some type of felt ring inside it (see pictures). I've never rebuilt a Mopar 340, only Chevy's.

First - what is it?
Second - do I need it with the new balancer that I'm installing?
Third - I have a 1969, 340 I think it's internally balanced can you all please
confirm that for me?
Fourth - Do I need to add any of the counter weights that come with the new balancer?

Thanks for all of your help.

Dave
 

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#2 ·
The felt ring is just to keep grit out of the seal, a case of Chrysler spending money and effort on a non problem.

The 340 is externally balanced and needs some of the counterweights, they should have markings on them for the 340 or 360 cranks.

Chrysler used several different pulley bolt patterns on their dampers, you need to check that the replacement damper will accept your engine's pulley bolt pattern before you do anything else.

Bogie
 
#3 ·
340 Harmonic Balancer

The only 340 balancers that were externally balanced were the late 1972 and all the 1973 engines. You shouldn't need any of those extra weights. Lay the new balancer on top of the original on, lining the keyways up and compare to see if the timing marks are the same. If not you won't be able to time it. Reason is: 69 and earlier 273, 318, and 340 used the cast iron water pump with the bottom outlet on the drivers side, so that timing marks are on the passenger side. In 1970 they switched to an aluminum water pump with the bottom outlet on the passenger side with the timing marks on the drivers side.. Most of the times these places only make their products for the 70 and up. If the marks are not the same you will need to get a 70 up timing cover. But beware the 69 and earlier and the 70 up use all different pulleys and brackets, nothing will line up or work right if you mix the 2. You say you have a 69 engine, does it have the cast iron water pump. Post if you need some more info or PM me. Good Luck
 
#4 ·
Has the engine ever been apart before and do you know if it still has it's original forged crank? If forged, it's internally balance from the factory and the balancer will be neutral balance but man, it's not easy these days to find a 340 that still has it's original part and has never had anyone mess with and do dumb sheet to them....
 
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