balancer, flexplate, and converter alignment

[jgfiveoh]

i just noticed a lot of q's popping up about the engine balance recently and it kind of made me wonder if it was possible to bolt up the flexplate and converter out of sequence with the balancer? since my build i haven't noticed any bad vibrations from my engine or anything besides the idle of the E cam, but nothing at speed. just something i was questioning.

also during my build i reused my 117K balancer and had the engine balanced with it also. doesn't seem to have any problems though. i was curious if that was a bad idea? if so, should i get a new harmonic balancer? and could a new harm bal. throw off the balance of my engine b/c i had it balanced with the old one.

 

[jrichker]

The balancer is keyed & the flexplate only bolts up one way to the engine. The only thing that could go wrong is to use a balancer that didn't match the engine balance, like a 28 oz balancer used on a 50 oz balance engine.

 

[BlownFiveLiter]

jrichker is correct. At first glance, the flexplate appears that you could bolt it on incorrectly, but the mounting holes aren't evenly spaced, so you'd have to spin it around until the holes line up correctly.

 

[jgfiveoh]

i should have known that since i installed the flexplate myself. i guess i couldn't really remember though, as i've done alot to the car since. thanks for clearing that up for me, i guess it just had me worried for a lil.

what about the balancer? can i get a new one and put it on even though i had the machine shop balance the engine with my old 117K balancer? will this affect anything?

 

[rd]

On the balancer, the formal procedure is to take the new one and the old one to the same balance shop (if possible) and have the new one checked or balanced to match the old one.

In practical terms, you could bolt it on, and probably be no worse off than stock.

However, for reasons I don't fully understand, I had 3 balancers fail on my 79. The original slipped the outer ring and shook like heck. The next two just cracked, one breaking the bolt and fallingl off. Both were oem Ford dealer replacements.

I put the original 78 t-bird stock unit that came with the crank on it, and its run fine, to 6k, for about 6 years now.

The replacement for that engine got balanced and a Fluidamper, that has been fine since 00.

 

[jgfiveoh]

i'm assuming that they machinist just needs the old and new balancer and nothing else correct? thanks for your help everyone.