Flexplate Question

-
FlDart360

FlDart360

Well-Known Member
Joined
May 30, 2016
Messages
238
Reaction score
127
Location
FL ,Zero Elevation
Finally got some time last night to try and start eliminating things that could cause vibration. I pulled the inspection plate on the 727 just to see how much I could learn about the flywheel and torque converter. My knowledge is pretty limited here but shouldn’t this be perfectly round? I don’t know what’s going on here with the white witness marks unless it was an attempt on balancing this thing? Any thoughts from those knowledgeable in this area the motor is a 360 LA so if I have read correctly from previous post the flywheel should be neutral and the torque converter balanced???



IMG_0329.JPG.jpg
 
You have a neutral balanced converter, and a B&M flexplate.
The balance will be correct.
 
Whats the back story on the 360? Rebuilt? If so was it Zero/neutral balanced or balanced stock external?
 
Dano I don't know the backstory on the motor just that the PO said he bought it off ebay. Sireland67 are you saying that chunk missing is the way the flexplate came?
 
Last edited:
It is used to balance a neutral balanced converter, behind a external balance engine.
 
That’s right, the flexplate is balanced so u can run a neutral balanced converter. Unless of course it’s the wrong flexplate. There should be a number on it for u see. Or a sticker. Kim
 
Thanks everyone i'll start looking at other possibilities for this vibration issue. I did notice while i was under the car poking around that one of my headers is hitting the torsion Bar.
 
If you are positive it is a 360, you need to figure out how the engine is balanced. Take a look at the harmonic balancer. It should either have a weight added, or, weight taken off. If the balancer is a facory one, that is. If it was nuetral balanced, That flexplate will cause vibration.
 
When does the vibration occur? While driving? Idling? All the time? All rpm?
 
Witness marks are generally used to make sure used items go back together in the same alignment that they came apart in. Some people do this for things like driveshaft universal joints, distributor bases, dismounting and mounting a tire. Things that spin.
 
FlDart360 said:
I can recreate it sitting in the driveway in park. It starts becoming evident about 2800 RPM and up.
Click to expand...
If it does it in N/P........, and not at idle, oh-oh.
By 2800, if it had a street cam at all; by this time it should be real smooth; not starting to vibrate. It looks like you have a slight imbalance in the engine; but try backing off the timing by disconnecting the Vcan first. If the can is already out of order, crank the D back about 10 degrees. Just reach over there and tug on the D. If it smooths out, you have some ignition work to do first.
 
AJ/FormS said:
If it does it in N/P........, and not at idle, oh-oh.
By 2800, if it had a street cam at all; by this time it should be real smooth; not starting to vibrate. It looks like you have a slight imbalance in the engine; but try backing off the timing by disconnecting the Vcan first. If the can is already out of order, crank the D back about 10 degrees. Just reach over there and tug on the D. If it smooths out, you have some ignition work to do first.
Click to expand...

Thanks AJ will check on that this weekend when i get some garage time.
 
You must log in or register to reply here.
-

Back
Top