External Balance Question?

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moparspares

moparspares

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My balancer is a powerforce balancer and I have a 1999 360 Magnum Engine 408 stroker - cast crank. I took the balancer off today to add some timing tape and noticed the bolt on weight. I checked against the powerforce instructions and the weight matched no 2 below. My engine machinest did the balancing and am thinking he has just made a mistake. Would there be an circumstance whereas he would have bolted in a different weight. He did have my block, crank, rods and the convertor and told me he would balance as well as the machining. I might add this was a couple of years ago so he would no longer remember if I asked him.

Small Block Chrysler V8 Engines
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All 273, 318, 340 and 360 cid V8s including Magnum.

How to Determine Which Counterweight to use:
1. All internally balanced 1967 and later 318 V8 standard and Magnum, all
internally balanced 273 and 340 engines with forged cranks: Do not use any
of the counterweights for these applications.
2. 340 externally balanced 1972-’73 engines with cast crank. Use counter-
weight #91014. (Pt. No. is stamped on weight.)
3. 360 externally balanced 1993-’97 engines with cast crank. Use counter-
weight #91013. (Pt. No. is stamped on weight.)
4. 360 externally balanced 1971-’92 engines with cast crank. Use counter-
weight #91012. (Pt. No. is stamped on weight.)
 
If he also included the damper when he balanced the rotating assembly I would not change the counter weight. Do you have a lot of vibration? 65'
 
As long as it does not have unusual vibrations while running, like '65 mentioned, there is nothing at all to worry about. It was balanced that way, so you'll always have to stay with a balancer weighted that way, but that's not a problem. Maybe your combination of parts would have required extra heavy metal to balance properly, so it was cheaper and easier to just go with an external weighted balancer.
 
I'm going to suggest the guy new what he was doing, being that the one he chose would have offered just that extra needed amount of off set (4.22 inch-ounce) rather than doing it this rather expensive way, see pic
100_0961.JPG
 
And if the converter you provided is weighted in an imbalanced fashion, he may have wanted to match that.... not that it is critical, but it just might seem more symmetrical, front to back.
 
Most every stroker kit out there is an internal balance set up. The base engine aty this point has zero to do with the balance instructions with your dampere.

I've never balanced an assembly, internal or external, with a converter attached. Unless he has a fixture to hold the guts of the converter in place, that's an imbalance issue waiting to happen. Pick up your converter and shake it, stuff moves around inside.
 
This may just have been a purchased cast, stroker crank.. external weights or Mallory or not depends on the rods, pistons, etc., and the resulting bobweight. We just dunno all of the info needed.

OP, it would not hurt to check back with your shop... they might have some data or memories.
 
nm9stheham said:
And if the converter you provided is weighted in an imbalanced fashion, he may have wanted to match that.... not that it is critical, but it just might seem more symmetrical, front to back.
Click to expand...

I bought a PTC convertor from Cope Racing Transmissions and I didnt see any weights attached on the outside of it so I am assuming it is zero balanced.


crackedback said:
Most every stroker kit out there is an internal balance set up. The base engine aty this point has zero to do with the balance instructions with your dampere.

I've never balanced an assembly, internal or external, with a converter attached. Unless he has a fixture to hold the guts of the converter in place, that's an imbalance issue waiting to happen. Pick up your converter and shake it, stuff moves around inside.
Click to expand...

Im not sure if he had a fixture or not or maybe he just wanted to see all the parts I was using making sure the convertor did not have any weights attached
 
I checked back through all my invoices and the crank I purchased from Mancini was the Mopar performance P5007258-CL (not sure what CL means) cast 4.00 stroke crank which I was told was an external balance crank and was always under this impression and Mancini site says require balancing. They also have a P5007258 which is also cast but is an Internal balance. I am also using the B&M flexplate with the cutout which was also left with engine machinest.

B&M.jpg
 
"Off set" on the front and also "off set" on the back, starting to look like a balanced combo to me!
 
If you had the motor professionally balanced he did it the best way he could
hope you have the component weights written down and the bob weight used
don's screw with it
 
Requiring balance does not mean external. There is a "Target" bobweight that you'd like to have. If the bobweight is different, it requires balancing.

Those crannks were done by Scat IIRC. None of them that I know of were ever an external balance set up.
 
Any crank can have external weighting added (or 'anti-weighting' in the case of the flexplate) if the bobweight is too high for the built-in counterweights.
 
contact the machine shop and see if he has a copy in their file of the balance job......the shop her in vegas gives you a copy and keeps a copy on file...
 
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