360 la weighted flex plate do I need to rebalance?

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Josshh70

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Hello guys, recently I had my crank balanced on my 360 la I had it balanced with an unweighted stock square style flex plate. Well come to find out the torque converter I ordered from PATC they forgot to put the butterfly weight on it, however I did order the proper torque converter for a 360la and I called and the guy said "well I wouldn't ever forget something like that". Sos here's my question should I have the crank re-balanced if I switch over to a b&m weighted flex plate or will I be okay running it the way the balanced it with the OEM flex plate?
 
Define "balanced". Is this still yet an externally balanced engine, or did you have it modified for "neutral" balance. There is room for a lot of misinterpretation, here.

EG If it's a "as stock" external balance engine, and you had a shop "balance the assembly" as such, it would have had to be balanced with the weighted balancer you are going to use, and the flywheel/ converter you are going to use, (or a weighted BM style flex plate for use with neutral converter)

On the other hand if you had it modified --as with Mallory Metal, etc---to become a neutral balance engine, then you want all neutral components, ALL--balancer, converter, flywheel, flex plate etc
 
67Dart273 said:
Define "balanced". Is this still yet an externally balanced engine, or did you have it modified for "neutral" balance. There is room for a lot of misinterpretation, here.

EG If it's a "as stock" external balance engine, and you had a shop "balance the assembly" as such, it would have had to be balanced with the weighted balancer you are going to use, and the flywheel/ converter you are going to use, (or a weighted BM style flex plate for use with neutral converter)

On the other hand if you had it modified --as with Mallory Metal, etc---to become a neutral balance engine, then you want all neutral components, ALL--balancer, converter, flywheel, flex plate etc
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I had them balance the assembly I got new rods, and Pistons. I had them balance those along with a new harmonic balancer and the OEM style square flex plate, he told me to stick with external balance as to add Mallory would be a fortune. So to answer your question in short I had him balance the assembly with the new rods, Pistons, harmonic balancer and OEM style flex plate.
 
So, what you're saying is that your engine IS still externally balanced; and NOT internally (i.e. neutral) balanced, correct?
Then you should be fine with the B&M 10239 flexplate (if using a 904) or 10236 (if using a 727).
BTW, I would confirm with PATC (with pictures) that you actually do have a neutral balance convertor, and either get the correct one that you ordered or be compensated for your trouble; and not just give him a pass with "Well, I wouldn't ever forget something like that". That's BS. Would make me wonder what else didn't get done "quite right"...
 
Professor Fate said:
So, what you're saying is that your engine IS still externally balanced; and NOT internally (i.e. neutral) balanced, correct?
Then you should be fine with the B&M 10239 flexplate (if using a 904) or 10236 (if using a 727).
BTW, I would confirm with PATC (with pictures) that you actually do have a neutral balance convertor, and either get the correct one that you ordered or be compensated for your trouble; and not just give him a pass with "Well, I wouldn't ever forget something like that". That's BS. Would make me wonder what else didn't get done "quite right"...
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Yes my engine is still EXTERNALLY balanced. And I will be using a 46rh transmission behind the engine, and when I called PATC after the guy said I wouldn't miss something like that I then asked what could you guys do send me a shipping label and send it back to put the weight on or whatever. I also asked if maybe he put the weight elsewhere on the converter and he simply said nope if it's not on the front then there are no weights on it at all. He told me I could also ship it back but I would have to pay return shipping I live in MI and patc is in Louisiana, can't imagine the shipping on that. Or he said I could buy a b&m flex plate, really not much of any help IMHO.
 
I had them balance those along with a new harmonic balancer and the OEM style square flex plate
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I don’t know how you balance the crank for an externally balanced 360 with the stock neutral balance flex plate on it.

It’s pretty simple though....... if the rear of the crank still requires the external weight........ and the converter doesn’t have it....... you’ll need the weighted flex plate.
 
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PRH said:
I don’t know how you balance the crank for an externally balanced 360 with the stock neutral balance flex plate on it.

It’s pretty simple though....... if the rear of the crank still requires the external weight........ and the converter doesn’t have it....... you’ll need the weighted flex plate.
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I just didn't know if it would affect the balancing of the crank as they didn't balance it with the weighted flex plate, looks like I'll just order up a b&m flex plate and call it a day.
 
If a 46RH is the same as a 518, the above linked flex plate will work. There were never any weights added to flex plates on small blocks of the LA version. 5.9's, yes they had weights on the flex plate, but a 360 LA....NO. You're on the right track, so good luck with it. :)
 
Josshh70 said:
Yes my engine is still EXTERNALLY balanced. And I will be using a 46rh transmission behind the engine, and when I called PATC after the guy said I wouldn't miss something like that I then asked what could you guys do send me a shipping label and send it back to put the weight on or whatever. I also asked if maybe he put the weight elsewhere on the converter and he simply said nope if it's not on the front then there are no weights on it at all. He told me I could also ship it back but I would have to pay return shipping I live in MI and patc is in Louisiana, can't imagine the shipping on that. Or he said I could buy a b&m flex plate, really not much of any help IMHO.
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This is their screwup and not yours. If they won't pick up the tab for their mistake, I'd dispute the charge with your credit card company- you did not receive what you ordered.
 
Professor Fate said:
This is their screwup and not yours. If they won't pick up the tab for their mistake, I'd dispute the charge with your credit card company- you did not receive what you ordered.
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When they balanced my first engine build in my dart it was an external balanced he used the stock harmonic balancer, one with counter weight and a B+M counter weighted flex plate as the B and M torque converter was not counter weighted. Engine ran very smooth. Second build used a scat forged steel assembly internal balance bought harmonic balancer from scat had machine shop cut counter weight off flex plate in lathe and neutral balance it. Assembled it and it run real smooth. The difference in bob weight from stock with trw 12.5 pistons to scat rotating assembly with icon 10.5 pistons is almost unbelievable almost a lb. very happy with scat’s products and service
 
"well I wouldn't ever forget something like that"
So you ask the guy who balanced the engine what flex plate and converter to use to go with his balance. Everybody else is just guessing what you need.
 
IQ52 said:
"well I wouldn't ever forget something like that"
So you ask the guy who balanced the engine what flex plate and converter to use to go with his balance. Everybody else is just guessing what you need.
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TRUE. Believe the man
 
I just didn't know if it would affect the balancing of the crank as they didn't balance it with the weighted flex plate
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This is my point.......
You can’t balance a crank that requires external weight...... without the weight.

The weight is part of the balance.
 
IQ52 said:
"well I wouldn't ever forget something like that"
So you ask the guy who balanced the engine what flex plate and converter to use to go with his balance. Everybody else is just guessing what you need.
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How much valve spring pressure should I use on my cylinder heads. I don't know what cam the installer used but he said didn't forget to time the camshaft.
 
Did he provide you with a print out on the balancing of the engine?
 
IQ52 said:
How much valve spring pressure should I use on my cylinder heads. I don't know what cam the installer used but he said didn't forget to time the camshaft.
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Can shaft timeing is done by key ways in cam gearing and machined dots on gears plus or minus your split key
 
Good Lord. Will I ever learn to just be quiet?
 
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