42RH behind Int. balanced engine

[RogerRamRod]

I’ve gone & gotten myself confused.
Looking at another thread, someone’s talking about symmetrical bolt circles, yet that doesn’t seem to be what I have. Somewhere I read that all 318 and 5.2 are internally balanced. Looking at rock auto, 96 and newer flexplate really doesn’t mention weighting, but 95 specifically says w/o weight.
I ordered and internally balanced crank for a 5.9, connecting it to a 42 RH from a 88 3.9 Dakota with a slotted pump drive.
I believe I’m correct that I need to get a neutral balance converter with a slotted drive.
I would also need a neutral balance flexplate with 10 inch bolt spacing. But I’m reading also that they changed the bolt pattern so early and late wouldn’t get mixed up.
Sorry this is so long
Would I just get a neutral balance converter with a 10 inch bolt pattern,
And a flex plate for a ?? year 5.2, and if the converter bolt holes don’t lineup, just weld up the one that doesn’t match and re-drill it
5.2 and 5.9 crank bolt patterns are the same for all years correct?

 

[Bobzilla]

What is your engine combo? I got lost with the talk of 5.2 and then 5.9 internal balanced crank.
Short version that always applies is, the flex plate and converter are ordered to match the application and balance weight.

If your engine is internally balanced, you would get a neutral balance converter and neutral balance flex plate.

If your engine is external balanced, you figure out what flex plate is available and order converter accordingly. If the flex plate has the weight, the converter will be neutral. If the flex plate is neutral the converter must be weighted.

 

[dirty white boy]

Magnumswap.com - Your source for Dodge Magnum and Mopar engine swap tech.

 

[RogerRamRod]

Thanks for your replies.
Bob,
I have a 5.9 that now has a balanced rotating assembly, so was looking at flexplates for 5.2 because from my understanding, those were always (?) internally balanced whereas the 5.9s weren’t. More confusion was added because 95 & back lists a different plate than 96+ on 5.2.
I tried ordering a neutral neutral from summit because I figured they would better understand than regular joe parts store, but not really. The guy was telling me it won’t work because a 5.9 is external balance, so I was trying to figure out what balanced engine I could say it was so I could get it ordered.
Dirty dude, thank you

 

[67Dart273]

None of the crank bolt patterns ever changed EXCEPT for some weird industrial 8 bolt cranks, and the early (er than 68) small center cranks, neither of which applies here

You can use either an LA flex which does NOT have a symmetrical pattern--and deal with the odd bolt hole--or use a magnum based flex with no weights. "I would think" a 5.2 magnum would work but you might have to remove some small weighting.

If you are unaware, the whole reason for odd bolt pattern was to key the older LA converters--which were weighted--to the proper clocking re: the crank. Magnum weighting was done on the flex plate instead, which means only the flex plate needs to be clocked

You are right--with a fully neutral balanced 360/ 5.9 you need a neutral converter, flex, AND balancer

It really would be better to have gotten the balancer, the flex/ converter, crank, and rod/ pistons weight and have the thing balanced as a "rotating assembly." Of course "more money, honey"

 

[Bobzilla]

Thanks for your replies.
Bob,
I have a 5.9 that now has a balanced rotating assembly, so was looking at flexplates for 5.2 because from my understanding, those were always (?) internally balanced whereas the 5.9s weren’t. More confusion was added because 95 & back lists a different plate than 96+ on 5.2.
I tried ordering a neutral neutral from summit because I figured they would better understand than regular joe parts store, but not really. The guy was telling me it won’t work because a 5.9 is external balance, so I was trying to figure out what balanced engine I could say it was so I could get it ordered.
Dirty dude, thank you

What part number crankshaft do a you have?

If you spent a bunch of money on, say, an Eagle forged crankshaft, that is likely internally balanced, but also likely assumes you intend to make lots of horsepower. In this case, stay away from stock replacement flex plates.

If you have any kind of cast crankshaft, it is likely still factory style external balanced.
Please be specific.

Edit to add:
I just found your question in another old thread that clarifies your combination;
Help with flexplate

If you are not running factory Magnum fuel injection, you can simply use the B&M neutral balance flex plate and a converter specified for your transmission but set up as neutral balance.