PastorTom1
Well-Known Member
Speakin' of ghosts in the drivetrain like harmonic vibrations, I know thay can be caused by a lot of components.........but don't overlook something because you "think" it's not possible.
I've dealt with quite a few if these problems in the past on old Mopars, but one in particular is worth another mention I think.
On my 74 Cuda, the previous owner had the motor (an earlier 340) rebuilt at a "reputable" shop with a lot of experience in Mopars. It was a nice internally balanced 340, to which they added a decent Edelbrock and Holley combo and a set of headers with a 2.5" dual set-up. The car sounded great.
They had also worked the 727 with a stall converter and shift kit, and it was nice and firm. The problem was that the set-up vibrated the dash and doors to the point that the owner just wanted it gone. He probably checked out the obvious for himself, or even got advice from the shop on what the problem could be.....who knows......I can imagine that they said the converter was mismatched or the driveshaft was screwy.......The motor hadn't been balanced when rebuilt, etc.........I've heard it all before.
After a week or so of thinking about it and "feeling" the car as I cruised it downstreet and back, I got some advice from "the guys" who actually drive these cars and work on them day to day. (Good move, huh?).
The driveshaft, tailshaft, u-joints and converter were all ruled out. Facing a worst case scenario, I was nearly despondent.........I finally got under the car with a strong flashlight, and had my wife bump the starter for me to completely turn the balancer.........looking at the back side from under the car, it was clear that they had a ton of paint on the thing......so much so that it obscured the "lines".....but, there it was........a stinking counterweight sunk into the rear valley of the balancer. I cleaned it off of excess paint, and removed the weight.
When I started the car, the vibration was gone........When I drove the car, it was smooth. How in the name of all that's intelligent they put the wrong balancer on this car I will never know........unless they had so many motors and parts laying around the shop that it was just a mix-up.......these guys rebuild motors every day......if they can't get it right, what do we do?
It's so unlikely, that it was dismissed almost entirely as a possibility.....but there it was.
I've dealt with quite a few if these problems in the past on old Mopars, but one in particular is worth another mention I think.
On my 74 Cuda, the previous owner had the motor (an earlier 340) rebuilt at a "reputable" shop with a lot of experience in Mopars. It was a nice internally balanced 340, to which they added a decent Edelbrock and Holley combo and a set of headers with a 2.5" dual set-up. The car sounded great.
They had also worked the 727 with a stall converter and shift kit, and it was nice and firm. The problem was that the set-up vibrated the dash and doors to the point that the owner just wanted it gone. He probably checked out the obvious for himself, or even got advice from the shop on what the problem could be.....who knows......I can imagine that they said the converter was mismatched or the driveshaft was screwy.......The motor hadn't been balanced when rebuilt, etc.........I've heard it all before.
After a week or so of thinking about it and "feeling" the car as I cruised it downstreet and back, I got some advice from "the guys" who actually drive these cars and work on them day to day. (Good move, huh?).
The driveshaft, tailshaft, u-joints and converter were all ruled out. Facing a worst case scenario, I was nearly despondent.........I finally got under the car with a strong flashlight, and had my wife bump the starter for me to completely turn the balancer.........looking at the back side from under the car, it was clear that they had a ton of paint on the thing......so much so that it obscured the "lines".....but, there it was........a stinking counterweight sunk into the rear valley of the balancer. I cleaned it off of excess paint, and removed the weight.
When I started the car, the vibration was gone........When I drove the car, it was smooth. How in the name of all that's intelligent they put the wrong balancer on this car I will never know........unless they had so many motors and parts laying around the shop that it was just a mix-up.......these guys rebuild motors every day......if they can't get it right, what do we do?
It's so unlikely, that it was dismissed almost entirely as a possibility.....but there it was.
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