5.9 Magnum Balance Converter Weights Information

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72DMag

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Hi everyone, I'm looking for some information in regards to the weights mopar performance use to sell that could be welded to the converter for an external balance of the 5.9 magnum. Mopar part number is P5249843. Does anyone know how many grams the weights are and the dimensions for them??

External balancing a magnum 360 and using a neutral balance sfi flexplate. B&M no longer makes the 5.9 magnum balanced flexplate so I need to add the weights to the converter.
 
Don't know if this will help or not, but just needed to do something for my buddy's 360 Magnum/46RE combo. Needed the earlier non-symmetrical converter bolt pattern flex plate with the crank position tone wheel. Had a guy that specializes in balancing spin a used stock '96-03 Magnum 360 weighted flexplate. I think it was 75 grams imbalance. I'll look for the paperwork tomorrow.

He milled through the back side of the 360 Magnum flexplate to remove the factory weight then transferred it to the earlier asymmetrical flexplate in the same spot. The weld added some weight, so he removed some material to get back down to the earlier measured imbalance. Both flexplates were indexed beforehand so the weight landed in the same position.
 
@Rob_Mopar If you can tell me the total weight he removed and any other details I'd appreciate that. I do have stock magnum flexplates I can rob the weights off of. Based on the original kit mopar used smaller square weights. So I'm not sure if the dimensions of the stock magnum weights would throw anything off. But based on your response it sounds like it won't. Thanks!
 
72DMag said:
@Rob_Mopar If you can tell me the total weight he removed and any other details I'd appreciate that. I do have stock magnum flexplates I can rob the weights off of. Based on the original kit mopar used smaller square weights. So I'm not sure if the dimensions of the stock magnum weights would throw anything off. But based on your response it sounds like it won't. Thanks!
Click to expand...

I'll see what I have when I get to the shop tomorrow. The weight removed was due to the extra weight added from the weld bead. Factory was spot welded. I'd see if someone could just remove some material from your SFI flexplate to get the same imbalance as a weighted stock one.
 
Thanks!! I also know the 94 and 95 magnum have the weight welded to the converter. But not sure what size converter the 46rh has and if that even matters for the weight. If not I might go to local yard jank a convert and weld it to my torque converter.

Also, there was a member on here who would send you the B&M template to cut the flexplate for an LA small block. Last I checked nobody has a magnum template available for something like that.
 
Well I believe I found the answer to my question. Looks like there is 91 grams on the converter for the 94-95 magnum. I'd assume the flexplate would have the same amount of weight for the 96 and up 5.9 magnums. Looks like these converters go one piece of steel welded to them. The original mopar kit came with 2 pieces and the instructions below. Should I do 2 45.5 gram pieces of metal on the converter or just one 91 gram piece of metal??


Links that show weight is 91 grams.:
Torque Converter A-518 (46-Rh 46-Re) A-618 (47-Rh 47-Re) Lockup
Visual: 5.2 or 5.9?

Directions for the original mopar kit:
SmallBlock-Magnum-Torque-Converter-Balance-Weight-Layout.jpg



This will be going on a 9 1/2" converter for the 904. I guess I'll have to do some math from the diagram above to figure out where to place the weights if I do 2 of them?
 
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Hughes engines is selling modified B&M flex plates to give the 5.9L Magnum balance offset. A little pricy, but if you are in a hurry it may be worth it.
Hughes Engines

Also, check out post 98 in this old thread where I added measurements for modifying a B&M 10230 neutral balance into a 5.9L Magnum balance. You will lose the SFI rating if modifying the flexplate.
Flexplate is not fits the torque converter
 
@Bobzilla thanks for link to the post for modifying the b&m flexplate.

If we know the weight is 91 grams. Is that how much gets removed from the b&m flexplate?? Asking as a way to check I took the right amount off the flexplate when modifying it.
 
I may be misunderstanding what you're doing, but if you are using a fairly stock 5.9 Magnum engine....you can use a factory 5.9 Magnum flex plate with an LA neutral balance converter. You simply have to file the edge of one hole out on the flex plate for it to work. Of course, if you are making a high HP engine and need an SFI flex plate, that's a whole different ball game. Good luck in your search.

:thumbsup:
 
I pulled the weight off of the stock magnum flexplate and got a weight of 100 grams not 91. I'm guessing when they are welded to the convereter chrysler estimated 9 grams for the weight of the welds.
 
@JDMopar You are correct that you can wobble out the one hole. I built a 360 with h beam rods and plan to spin it closer to 6400 rpm which is over what I feel comfortable the stock flexplate can handle. Also my converter has the larger bolts for racing. Drilling out all 4 holes and then wobbling out the 4th hole even more just didn't seem safe when I plan to hit 100 mph in the 1/8 mile.
 
@Bobzilla

Thanks for the measurements. Here is mine replicating what you measured. Yeah I know it's not as pretty but I measured all points to what you had in the thread. If census from you is that this looks about right I'm gonna go ahead and cut it and weigh it too before and after the cut.

Let me know if I should proceed. If we mess it up it's only money...... lmao

Resized_20210625_114416.jpeg
 
72DMag said:
@Bobzilla

Thanks for the measurements. Here is mine replicating what you measured. Yeah I know it's not as pretty but I measured all points to what you had in the thread. If census from you is that this looks about right I'm gonna go ahead and cut it and weigh it too before and after the cut.

Let me know if I should proceed. If we mess it up it's only money...... lmao

View attachment 1715756067
Click to expand...
You mentioned aftermarket connecting rods, so I have to ask if you matched the bob weight of the original parts? If not, this flex plate matching will likely not work.

As for your markup, that is pretty darn close. Double check your measurements and the line drawn on right side. All lines should go through the centerline of the bolt holes. Your right side line appears to use the right edge of that bolt hole, where my red line was. My lines were a little thick and that may not have been clear. After the lines are drawn, the measurements are from the lower edge of the bolt hole down to where the notch is going to be cut. This was so you can put a caliper or ruler right on that edge for closer measurement than estimating the hole center line. Otherwise, it looks like you should be good. I listed the weight in another thread on this issue and will add the link below. Final weight after cutting out the notch should be about 1389 grams total weight. Unmodified 10230 weight before cutting a notch was 1567 grams. The notch is more weight removal than the suggested 5.9 Magnum offset weight simply because it is a larger area and the flex plate itself starts off much heavier, so no worries there. A lighter flex plate with a heavy weight in the correct spot or the torque converter itself, like the factory did, uses less total weight on that point, but it works out the same when spun for balance.
Check out post 24 in this thread:
5.9 Magnum flex plate too small??!?!?!?!?
 
Yes parts are balanced to magnum bobweight. Local machine shop did it. I checked him and my math came out to be 2 grams lighter for the total bobweight. I'm guessing they add a few grams for the weight of oil. What I didn't realize when I was building this is that B&M hasn't made the magnum flexplate for years now. Found out the hard way.

You were right about the line on the right side. Your pic looked like you were aiming for the edge of that hole so thats what I did. I'll make the correction and weigh it before and after the cut. I did measure from the bottom of the holes to the edge of the cut but I will double check everything before cutting it here soon. Thanks!!
 
Well its done! Gonna trace it on a piece of cardboard before bolting it to the crank. I ended up with slightly different weights than you but our difference in weights was almost identical. Also, I do know external balancing gives you some +/- Leeway so that is why I decided to do this myself instead of sending to hughes. This is also why I'm not concerned if my weights are slightly off from yours. Finished flexplate is pictured below. Pic is of the engine side face down.

Your weight: Before - After = Diff
1567 - 1389 = 178 grams

Mine:
1573 - 1393 = 180 grams

Resized_20210625_140532.jpeg
 
Looks excellent and I would call those weights a dead on match to mine. Close enough anyways, since we are using different scales.
Looking forward to the results.
 
72DMag said:
Hi everyone, I'm looking for some information in regards to the weights mopar performance use to sell that could be welded to the converter for an external balance of the 5.9 magnum. Mopar part number is P5249843. Does anyone know how many grams the weights are and the dimensions for them??

External balancing a magnum 360 and using a neutral balance sfi flexplate. B&M no longer makes the 5.9 magnum balanced flexplate so I need to add the weights to the converter.
Click to expand...

Its spendy. But Huges race engines is soposed to sell a sfi magnum flex plate. Don't know if this would interest you or not.

Screenshot_20210705-120926_Google.jpg
 
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