Flexplate balancing?

[A.J.]

How important is it to have a flexplate balanced? I had to have the engine side tig welded and the torque converter side welds ground off on a lathe to fit the 2.4/31TH flex plate to a 10" converter. I found a place that "might" be able to do it but it's 5 days out. Anybody know how important this is? The diesel shop next to me gets theirs modified without balancing for the Cummins but they're only spinning about 4K and I'll be up to 6K.

[cordes]

IMO they're prone to breakage enough as it is. I wouldn't want it to be out of balance.

[turbovanman²]

Are they even balanced from the factory? Its a pretty light part with no inertia to it. Not sure I'd bother. Maybe throw it on the wheel balancer and see what comes up?

[A.J.]

So I called a few other places and no one could help me. The only place that said they could do it sounded like it wasn't necessary but would do it for me anyways. My thinking is alined with Simon, not much inertia so I'm not going to worry about it. I don't have a wheel balancer so I can't try that. I decided to put it on. I got 330 hp (according to the 1/4 mile calculator on MPTune) out of this one with out breaking before modifications. If it breaks with the modifications I'll post up about it.

[Reaper1]

My thing is that it is connected to a torque converter...which kind of acts like a giant fluid filled damper in a way. The flex plate's inertia is very small in comparison to the torque converter. Now, if this thing was spinning 10,000rpm, then yeah, I'd worry about it. 6,000....meh.

[cordes]

FWIW, I'm pretty sure they're balanced from the factory. I noticed a little tab welded onto one when I installed a trans in the NYer recently. I thought, hmmm... I guess they have to balance these.

[looneytuner]

I just noticed that B&M has a flexplate for our cars without the ring gear for double the stock price. Must be heavy duty?

[A.J.]

I just noticed that B&M has a flexplate for our cars without the ring gear for double the stock price. Must be heavy duty?

Do you have a link? I looked on Summit and couldn't find anything.

[looneytuner]

go to ebay. It's roughly $100

http://www.autopartswarehouse.com/sk...daflplB3210231

It says 85 but it's 8 bolt.

[turbovanman²]

go to ebay. It's roughly $100

http://www.autopartswarehouse.com/sk...daflplB3210231

It says 85 but it's 8 bolt.

Nice find. Remember, they always get our stuff wrong, remember the head stud fiasco?


Edit, that is for a V8 car-

http://www.jegs.com/i/B-M/130/10231/10002/-1

https://www.rebelperformance.com/tra...a-727-904.html

[Dr. Johny Dodge]

remembering the internal ballance vs external ballance pre 73 and 73 340 motors I believe I recall the converter gets the ballance weight welded to it

so if concerned with the ballance of the flex plate , why not bolt it to the converter and get both ballanced as a unit ?

granted you would need an index mark to be sure you bolt it up right in future

[looneytuner]

remembering the internal ballance vs external ballance pre 73 and 73 340 motors I believe I recall the converter gets the ballance weight welded to it

so if concerned with the ballance of the flex plate , why not bolt it to the converter and get both ballanced as a unit ?

granted you would need an index mark to be sure you bolt it up right in future

Ah, what the heck! I already made one mistake in this thread. If the engine is at #1 TDC and the flywheel just bolts on one way, the TQ should be bolted on with the timing mark straight up? So unless you make a (Looneytuner) mistake, they will be indexed.

[A.J.]

Ah, what the heck! I already made one mistake in this thread. If the engine is at #1 TDC and the flywheel just bolts on one way, the TQ should be bolted on with the timing mark straight up? So unless you make a (Looneytuner) mistake, they will be indexed.

The 41TE bolt pattern isn't indexed like the A413/31TH so if I had it balanced with the torque converter I'd have to mark it.

[zin]

Also, some of the internal parts of a converter aren't fixed, and so it cannot be precisely balanced as a unit... the fluid acts to smooth out minor imbalances, kind of like those "balancing beads" used in tires.

That said, it can only help to balance as many individual components (such as the flywheel) as possible (affordable). If you could take the converter apart, and balance the individual pieces, that would be great, and is done on some higher-end aftermarket converters (like Neal Chance, etc).

When in doubt, balance! It's one of the secrets to making endurance engines last, money well spent, even though it doesn't make HP... Well, there's my .02 again!

Mike

[wallace]

Balance it especially if you have welded on it. Any shop that balances should be able to help you out.