Crankshaft Balance on 440

Bayoulee

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I had a guy telling me that some 440s were internal vs external balanced. My builder is a 1975, and the transmission I was going to use is I believe a 1967. He said while some would bolt together, there would be terrible vibration. Any input on this? thank you
 
Not a big problem.

Yes internal and external balance engines exist. But the transmission has nothing to do with it, it is the torque converter with weights on it or not.
You can buy a flex plate to take car of this and run a converter with no weights.
 
What you really need to figure out is if your engine is internally or externally balanced. You can have a cast or a forged crank. If you have a cast crank, no doubt, it's externally balanced.

The forged crank version could have heavy (known as "six-pack") rods or the regular connecting rods. The regular rod version will be internally balanced and there's always discussion if the heavy rod version is internal or external. What I've read leans towards all the heavy rod motors from 1972 up being internally balanced, but I won't say that's gospel.

Identifying the balancer will help.... and of course, looking at the crank to see if it's forged and what rods are in it. In other words, look at what you have before you listen to "a guy".

The best balancer ID I've found: Harmonic Dampers 440 Source.com
 
You should start by determining which crank shaft and rods are in the engine. Generally 'a '75 engine would have a cast crank and the heavy rods and that engine would be externally balanced. Look at the harmonic balance that came off of the engine, if it is a cast crank unit, the center of the balancer will be egg shaped. The externally balanced engines also ran weights on the torque convertor as noted above. As noted, the conversion flex plate is the way to go to allow you to use your existing convertor. You should be sure that the engine builder retained the factory rods and crank before ordering the conversion flex plate.

Dave
 
when i bought my fury 20+ years ago it shook so bad i assumed it had a dead cylinder but i had another 440 so i didnt care and bought it anyway...turned out it had a 73 cast crank 440 (with the correct damper) and the 68 converter...the correct converter with the 2 extra weights took care of the issue
 
I had a guy telling me that some 440s were internal vs external balanced. My builder is a 1975, and the transmission I was going to use is I believe a 1967. He said while some would bolt together, there would be terrible vibration. Any input on this? thank you
Casting number on the crank would help verify whether external or internal balance.
For instance, my 1969 440 crank is Crankshaft Casting Number 2206160, forged steel, internal balance.

You could also compare your harmonic balancer to the internal and external balanced models shown here.
Harmonic Dampers 440 Source.com

After that, we could figure out what needs to be done to make your torque converter work with your engine.
 
The steel crank damper is thin, looks like a lot of other early dampers.

The cast crank has this big fat ugly damper, not to body shame a damper.

By '75, more than likely a cast crank.

What's odd about Chrysler was that with Chevy you had to get the absolute best Corvette engine to get a forged crank, but every Valiant with 225 on the street had one, a forged crank, nevermind all other engines. all of the V8's through 1971.

Things were going downhill fast in '72, I'd guess that's when cast cranks appeared.

A local racer here built many successful cast crank 360 engines/Duster that rivaled big blocks, so they can survive high perf applications.

He was my mentor when I was building my 383. I learned all the ins and outs of block blueprinting from him, deburring, polishing, this is inside the block, peening and polishing rods, chamber squish, porting/polishing heads, overlap, exhaust scavenging, windage, soldering and filing you own advance curves in distributors, etc, etc.
 
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