Shake rattle and roll

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chrysler kid

chrysler kid

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Well here I am spending another beautiful saturday pulling out my hair. I recently completed my magnum 360 swap on my cordoba. I opted for the v belt setup so I had a reputable shop build me a nuetral balance converter. I am using the flex plate that came with the 360 magnum and a blueprintengines dampner with different attachable weights. The car drives smooth but has a light "pulse" at certain rpms. I have a loose piece of trim on the dash you can hear vibrate as if the car has a pulse. The engine idle is constant but i definately can feel that there us something slightly off. I then ordered a mopar branded dampner from jegs that is the correct part number for a 360 magnum seperate from the crank pulley. Even in the description it says it is for running v belts with this motor. Well.. i install it and fire the car up with no pulleys and it shakes like a demon. Any suggestions or ideas as to what I am facing here?

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chrysler kid said:
Well here I am spending another beautiful saturday pulling out my hair. I recently completed my magnum 360 swap on my cordoba. I opted for the v belt setup so I had a reputable shop build me a nuetral balance converter. I am using the flex plate that came with the 360 magnum and a blueprintengines dampner with different attachable weights. The car drives smooth but has a light "pulse" at certain rpms. I have a loose piece of trim on the dash you can hear vibrate as if the car has a pulse. The engine idle is constant but i definately can feel that there us something slightly off. I then ordered a mopar branded dampner from jegs that is the correct part number for a 360 magnum seperate from the crank pulley. Even in the description it says it is for running v belts with this motor. Well.. i install it and fire the car up with no pulleys and it shakes like a demon. Any suggestions or ideas as to what I am facing here?

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Don't know, but I can tell you with near bout 100% certainty that the balancer in the front there is NOT a Magnum balancer. I could be wrong, but I don't think it is. I have no clue about the one with the removable weight......but if it shakes, obviously it's wrong. Did you run the engine up in park and neutral to eliminate a drive train vibration?
 
I did run it up in park the shake just gets worse. This is what jegs says but the part number doesnt match the number on the website. I also gound a few posts with guys using this part number on their 1970s la so it looks like a got a wrong part. At least it was only $300...

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You didn't say what year your Magnum engine or flexplate is, but the first couple years of 5.9s used a neutral flexplate and an externally balanced convertor, later years went to an externally balanced flexplate and a neutral convertor. I'm not sure what the cutoff date was, '94-'95? maybe others can chime in on that. I've personally only had '97 and up, but others swear that is how they did the first ones.
So, make sure your convertor has the balance weights on it, or you'll never get it sorted out.
 
The Machine shop I prefer to use only balances an engine with the balancer and the flywheel/ torque converter. It sucks because if you want a different stall speed.
Rebalance. Last one done the owner used my specs on file and balanced it for the engine. I thought zero was zero. But it made a difference.

I never knew you could buy a 360 from a big rebuilder neutral balanced.
 
The weight on the balancer looks more like a LA 360.
 
I think at this point your best bet is to have the engine professionally balanced. I know. I know. lol
 
Okay, we know you have a 2001 Magnum with the original flexplate. That's correct.

The converter is neutral balanced. That's correct.

The balancer in the background looks to be a multi-use balancer. I "think" the medium bolt in weight is correct for the Magnum. I agree with RRR, the front balancer is not correct. Do you have the other two sets of weights that came with the balancer? Maybe try the bigger weight.
 
I have been looking at pictures online of the LA vs. Magnum balancer and it is definately the wrong part. Just odd because it does have a matching part number with the jegs website for the magnum balancer i ordered but the picture shows a completely different balancer. Oh well. The vibration very minor on the universal dampner I have on it now and I am using the middle sized weight which is correct. Im just going to drive it until I can find the correct part. If I ever build a magnum again I will defiantely keep the serpentine setup and settle for an electric pump. It makes everything easier.
 
chrysler kid said:
I have been looking at pictures online of the LA vs. Magnum balancer and it is definately the wrong part. Just odd because it does have a matching part number with the jegs website for the magnum balancer i ordered but the picture shows a completely different balancer. Oh well. The vibration very minor on the universal dampner I have on it now and I am using the middle sized weight which is correct. Im just going to drive it until I can find the correct part. If I ever build a magnum again I will defiantely keep the serpentine setup and settle for an electric pump. It makes everything easier.
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You should not. It's that important. Being out of balance enough for you to feel it can pound the bearings right to pieces.
 
I would take a serpentine Magnum balancer and your universal one to a machine shop and see if they can make them match.
Universal usually means it doesn't fit anything..
I accidentally ran mismatched flywheels and balancers because apparently I don't read warning labels and it caused damage. I would echo what RRR said and not run it until you can be relatively certain it's right.

Was this engine overhauled? Or is this just a swap? A very minor pulse could also be a misfire, or a couple swapped plugs. I'd look real close at everything just to rule out all the small things that could have you chasing your tail.
 
Went through the same mess that you are experiencing with a stock Magnum serpentine set up on my Dart.
Bought three H. balancers before I got the one with multiple weights that actually worked. Do not remember which one was correct.
However, since it was made in China (GAG) the crank hole was TOO SMALL. What! It would not fit on the crank. Had to have a machine shop bore it to fit.
So, keep on fighting. And, assume that if it is made by anyone except Mopar to measure everything.
A friend back East had one that the keyway was off compared to stock.
"It is always Something"( Rose Ann Roseanna Danna )
 
Update:
So I found an early style magnum balancer in decent shape and installed it but I am still having the same engine "throbbing" at idle and cruising. It is definatley more prevalent when the engine is warmed up. The engine always stays nice and cold. It is not a full rebuild I found a rolled truck with 102k on the odometer. I tested the compression when I first picked it up a year ago and it was running good numbers. The motor was visibly clean when i pulled it apart almost no gunk or carbon. No scoring on the main bearings ot other signs of damage. I have ran a vacuum gauge it sits perfectly steady at 21. Fuel pressure is steady at 7 psi. Good oil pressure. Carburetor is a 1405 edelbrock that ran flawlessly on the old motor. I double checked the plug gap. The new plugs have maybe 4k miles and all look like theyre brand new no indicators there. Played with the idle on carb. Used starting fluid to check for vacuum leaks. Stock magnum cam, the timing was set at 14 degrees. I brought it back to 6 which is stock for a 78 smog era cordoba la 360. Still cant figure this one out. I know the exhaust is a bit constricted (la manifolds with a stock cat) but its not sluggish. Just has a surging vibration driving me crazy. You can feel it in the steering wheel once its warm.
 
Have you checked the casting number on the side of the block to make sure it's not a 318?
 
Came out of a 2001 dodge 2500. Had fuel injection, serpentine belt, vertical intake bolts, no nylon cam gear, a timing case with no fuel pump hole, theres no rocker shaft like the la would have. I didnt check up the casting number but Its definately a magnum
 
What ignition system are you running? Maybe something going on there???
 
Electronic ignition. Same ignition module, coil, and ballast resistor i had working fine on the previous setup. The plugs and wires are new. I didnt use the distributor from the old setup i used an new aftermarket stock distributor ive had sitting around with new cap and rotor. I double checked cap and rotor after running it they still looked new. The weights in this distributor dont open up as quick as ide like but nothing concerning. All the wiring is the same i just pulled the harness at the bulkhead to clean connections and add looms. Everything hooked back up correctly and tight.
 
Play with the timing, after you confirm its not a 318. Engine size is cast right above the starter.
 
Do you still have the other distributor? There are lots of new Mopar distributors floating around with Rotor/Reluctor phasing errors.... Bolting in a known good part is cheap & easy...
 
1WildRT said:
Do you still have the other distributor? There are lots of new Mopar distributors floating around with Rotor/Reluctor phasing errors.... Bolting in a known good part is cheap & easy...
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Very true. Even if it doesnt fix the issue it will give me time to change the springs in the aftermarket one.
 
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