Same o same o 360 balance problem

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1967bcuda

1967bcuda

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HELP! My 360 is out of balance! So I bought a 360 out of a 87 Dodge truck with a manual transmission and put a 727 behind it. It didn't have a harmonic balancer so I got one off a 75 360 automatic & have the b& m flex plate for external balance 360 on it and it shakes to beat the band. Does it need to have a manual trans balancer on it? I read they're 3 lbs heavier than an automatic. Any help would be appreciated
 
Maybe you bought a 318.
 
No, it's a 360. Casting on block is 360 and I had to order a new oil pan for it
 
What does your converter look like? You sure it was not already weighted? What is that history?

There is no difference between manual and auto 360s unless maybe the pilot recess was not finish machined
 
torque converter? stock engine specs? what b&m flex plate is it? if i were you i would dig and get part numbers off balancer, flex plate, and torque converter.

i once bought a valiant with a 360 in it but they used a 318 trans and it took me a minute to figure out the issue but it was simple once i figured out where to look. i ended up welding weights on the t.c. and all was good.
 
Be aware that there are 2 B&M flex plates with the 'bite' out of one edge. The one for the 360 has a the larger bite; the cast crank 340 has a smaller bite. They cannot be swapped without balance problems. So be sure you have the correct one. Yours should look exactly like this, and have a smaller bite out of the edge: http://www.manciniracing.com/19exbal360wi1.html

The issue is probably because the torque converter has the weight still on it, and that cannot be used along with the B&M plate. Pull the inspection plate and look for a TC weight; if found, you need to remove it or put in a balanced flex plate, or change to a non-wieghted TC.

FWIW, another poster recently found he had a bad fan clutch causing vibrations.
 
nm9stheham said:
The issue is probably because the torque converter has the weight still on it, and that cannot be used along with the B&M plate. Pull the inspection plate and look for a TC weight; if found, you need to remove it or put in a balanced flex plate, or change to a non-wieghted TC.
Click to expand...

I'm betting this.... ^^^^^
 
OK guys. B & M flex plate #10236, Jegs 11" torque convertor 2500 - 2800 stall # 555 - 60408 .040 over flat tops, Comp Cams big mutha thumpr cam cloyes double roller chain sealed power rings and bearings melling oil pump
 
as suggested before, inspect torque converter for weights. then inspect driveshaft, also what fan setup do you have?
 
according to part number...it does not come with weights on the converter...says to use B&M flexplate

Neutral balance
Converter requires B&M Flexplate with 10" bolt circle and correct counterweight for specific application
 
Well damn I don't know. Bell housing alignment? driveshaft?

Piston / rod weight compared to factory?
 
I had the same issue. 360 external balance with stock flexplate. Put in a b&m 360 flexplate and ground the weight off the converter thinking it would make it a neutral. Didn't work. Ended up changing to a new neutral balance converter and 360 b&m flexplate. Problem solved.
 
Yes. It vibrates in park. I have the stock flex fan direct bolt to the water pump. Stock 727 and driveshaft. Put new u joints in about a year ago.
 
if it vibrates in park it is not driveshaft or tires. try it without fan. maybe the counterweighted outer ring of the damper/balancer has slipped on the rubber! the damper is obviously counterweighted right?
 
Flexplate and TC parts numbers look good for your combo. But, it still could be a bad TC. Are all the TC bolts in place and the same size heads?

Next to investigate is:
- Damper.... is it the right one? It should have letters cast into it that say something like: "For 360 only...." etc. (As far as i know, the damper is the same for auto and manual trans, BTW.)
- Pull off the belts and idle it and see if anything changes just to eliminate that.
- The thought about the recess in the back of the crank is a good one. If it was not machined out for the nose of the auto trans TC, then the bolt up of the TC to the flex plate will be all hosed up. When you mated the trans to the engine, you should have been able to pull the TC right up to the flex plate with your fingers alone and with no real resistance. If there was a gap between the TC and flax plate that you had to close up by pulling in the TC bolts, then that is a bad scene.
- We need to know what pistons were used; the statement of ".040 over flat tops" indicates that they are not stock replacement pistons. If lighter hypereutectics, then the crank and rotating assembly will be out of balance if it was not re-balanced. Were the original rods re-used?
 
I had an ATI converter that caused a vibration. It was an internal issue. Had to exchange the converter. Won't tell you the hassles they put me through. If the other ideas don't help, you may have to put the old converter in to see.
 
I'm not sure the 360 dampener will have stamping, I thought only 340's were stamped.
 
Hot Rod Garage recently had a similar problem. It turned out to be their torque converter. It shook so bad that they broke the flex plate.
 
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