Have a vibration...

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grassy

grassy

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Folks,

I have a vibration when the engine is running. My mechanic thought it was a engine mount on the frame problem but I have that eliminated. It is a 360. Af far as I know, everything is balanced. The torque , if I remember, was weighted...it was a Chrysler producd but I have lost the model number.

The only think I can think of is the torque converter...I thought of unbolting it from the flex plate and push it back...no vibration. ..then it is the converter..

Vibration still..flex plate..

That will not work...because the starter uses the torque converter to start the engine..

Is there any way else to test to see where the problem is ?

Should the car not be driven now ?

Thanks
Ian.
 
Since you didn't say i just installed a 360 or i just replaced wires or i changed the trans, you're kinda explaining this as you have been using the car and now today it is having a issue.

So if thats the case and it's not a incorrect firing order i would point you to the flex plate and balancer.
If either of those aren't showing sings of broken, slipped or cracks, then start pulling plug wires till there is a noticeable change.

.
 
take the transmission inspection cover off and look and see if it threw off the weights.

Does the engine have a miss too ,or just the vibration?
 
Sorry...a bit freaked out at the moment.

I just installed the engine/trans combo. No misses...just vibration. Oddly enough, it disappears during some speeds / rpm.

It is hard to tell where because all tires are out of balance. That will be rectified tomorrow am. Haven't driven it much. Really needs to be used on Tuesday for prom.

Thanx
 
as menioned above, check the convertor for weights. 360 has one large triangular weight.
 
An incompatibility between the flex plate and converter. Replacing flex plate.

ian.
 
grassy said:
Sorry...a bit freaked out at the moment.

I just installed the engine/trans combo. No misses...just vibration. Oddly enough, it disappears during some speeds / rpm.

It is hard to tell where because all tires are out of balance. That will be rectified tomorrow am. Haven't driven it much. Really needs to be used on Tuesday for prom.

Thanx
Click to expand...

Out of balance tires can induce all sorts of strange vibrations. Are they flat spotted from sitting too?

Was the trans and engine combo already together in another running car?,or did you joint them from different sources? What year engine trans is it? When up to speed and the car is put in neutral with the engine now idling, does the vibration go away or subside significantly?

When sitting in Park or neutral and the engine is brought up to freeway speeds, does it vibrate then?
 
original 340's were internally balanced. harmonic balancer was neutral. crank was balanced with rods/pistons weight. flex plate was neutral balanced. torque converter was neutral balanced. (or flywheel)

then the 340's went to cast cranks. harmonic balancer had an offset. crank was balanced with rods/pistons weight and harmonic balancer and flexplate/torque converter or flywheel attached. flex plate was neutral balanced. torque converter had offset weights. (or flywheel had holes milled)

360's followed the cast crank model. the harmonic balancer is specific to 360's, it has an offset
your torque converter will have weights if you have the stock (neutral balanced) flexplate. if you use the B&M flexplate with the notch cut out, you use a neutral balanced torque converter. (in other words the flexplate OR the torque converter will have an offset balance NOT BOTH)

if you have a stroker with a forged crank, then your harmonic balancer will be a neutral balanced aftermarket, your flexplate will be neutral balanced and your torque converter will be neutral balanced. (it's now an internally balanced engine with the forged crank)

if this doesnt make sense i'd recommend doing lots of research on the differences between internal / external balanced engines.
 
The vibration is from an incompatibility between the flex plate and converter. The harmonic balancer is correct. Both flex plate and TQ are for the 360 but not in their existing combination. . Some of the info i gathered was incorrect and I assume, I made an incorrect assumption along the way...my fault.:banghead::banghead::banghead: Won't do that again...

Both units are for the 360 (cast date year of '79) .

The vibration will be rectified this mistake by installing a different flex plate.:sad11:

Thanks all for your help.

Ian.
 
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