360 balance ?s

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MoparAGoGo

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I have had quite a vibration. I checked to see if I had a 360 converter. I believe I do, as it has a large weight on it. I also looked at my damper. Which I believe is fine. And it.has a recess in it. My questions are.
1 is it possible to install the flex plate backward?
2 is the weight supposed to be aligned with the recess?
the weights are on opposite sides. Should the heavy side of the damper be opposite the weight?
 
The keyway on the damper should, I believe, align with the #1 TDC. At that point, the timing marks should line up with TDC on the cover, as well. I may be incorrect on this.

The flexplate only goes one way that I've ever seen, thanks to offset crank bolts.

Does it vibrate at idle? Running at a certain speed? In neutral? In a certain gear? On jack stands?
 
At a real low idle it is smooth. Just off idle it shakes bad. And it turns into a vibration at higher rpms. This is in neutral. It is the same in gear. When starting out I shakes like it is missing real bad. But it runs good. Also shakes bad when coming to a stop. But on the highway it is just a vibration.
 
It has the old style damper. I am not sure if it was even apart. just trying to figure out what is happening.
I put 600 miles on it since Thursday. Runs great. Just shakes as I said.
 
sure its the right flexplate? if weights are on your converter then you don't need the special b&M style flexplate.
 
It's possible the harmonic damper has slipped or is slipping on the rubber ring, but I don't know if it could cause that kind of vibe issue.
 
I have never had any of my mopars shake like this before.. it is a 76 van.
I just have to share a pic..
IMAG0369.jpg
 
The weights will be opposite each other. Not possible to install a flex plate backward. Since the weight on the converter is located between the mounting pads it will be located in one of the recesses of the flexplate. It is a stock flexplate isn't it? If it is it needs a weighted converter, if it's a B&M or TCI flex plate it doesn't need a weighted verter. If it is a stock flexplate I wonder if it has the right weight on the verter cause Mopar had at least 4 different weighted converters that I know of. Had a buddy with a 440 in a Challenger that had a vibration like you describe and it turned out a very highly regarded trans. shop in PA had put a 360 converter behind it when it should have not had a weight at all cause it was a steel crank engine.
 
jos51700 said:
The keyway on the damper should, I believe, align with the #1 TDC. At that point, the timing marks should line up with TDC on the cover, as well. I may be incorrect on this.
Click to expand...

Can anyone else verify this to be true? It would be a place to start.
 
A couple things you can try but I would bet it has to come out and apart to be corrected.
First try a different dampner and see if it cures it, if not you can try adding some weight to the convertor at the spot where the weight is now and see if it gets better, or you can even knock the weight off the convertor and see if it improves or gets worse, it can easily be welded back on. But in my experience it is uncorrectable without rebalancing the rotating assy if it is not as simple as a spun dampner.
We just went thru a scenario almost identicle to this in my shop and after trying to diagnose the problem, replacing the dampner, then by adding weight to the convertor we ended up having to remove the engine and check the balance and it was way off. After correcting the balance problem the vibration was gone.
 
Well... That doesn't sound good. If I have to go through all that I will just change them out. I have a
Couple of small blocks laying around. I suppose I could live with it till something gives..
I have another 360 I will try swapping the damper and see what happens.
 
. Update.. I decided to bring #1 up to tdc I pulled the plug. Got it as close as i could to the top bumping it. And the damper timing mark was where it should have been so no slipping on the damper.I noticed my distributor was leaking oil, so i pulled it out. Replaced th o ring and gasket. Put it backtogether And fired it up to check the timing. And while watching it run from inside i found the problem. Damn fan clutch. The bearing went bad and it shifted to one side. I shot over to the parts store, picked one up and put it in... No more shaking!!
 
Glad you got it fixed cheap.
And the shaggin wagon is really cool.
 
Good to hear, I should not have assumed you already pulled the belt and started it to eliminate pulleys, fan and such.
That is one sharp looking van, reminds me of high school when a good friend of mine had one,his was a 79, had a 360 4bbl with headers in it, sum bich would haul ***. Was a lot of fun... many a late night, many a party... he had tear drop side windows, a bed, shag rug, fridge, crazy stero with I think 10 speakers, really decked out nice, paint was metalic brown, had a lot of fancy wooden hand crafted stuff in it too, between the partys and the girls... man... crazy days.
 
Awesome.. I wish I had been born 18 years earlier.. they sound like crazy Times. Not that growing up in the 80s-90s wasn't a good time.. things were a lot different then...
 
Vans are bitchin'...even a VW is cool when you go to party and are no good to drive, just crash in the back and sleep it off. Saved my *** more than once...literally!
 
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