Happy New Year everyone,
My 1970 Challenger has developed a vibration that can be felt and seen (I have a video, but it is too large to upload) in the steering wheel and also felt in the seat. The vibration occurs when the car is in park and continues while driving. It is there at all engine speeds, but more pronounced at 1200 to 2000 RPM. I said developed because I got the car on the road about a year ago and for the first 200 miles or so, I did not notice any vibration. The vibration seemed to start all of a sudden a few months ago and nothing that I've checked seems to be the source of the problem. The car currently has less than 400 miles on it since a total restoration. My suspension, wheel balance, and alignment guy drove the car and inspected it thoroughly for any loose or otherwise obvious problems. He said that the source of the vibration is not in the wheels/tires, driveshaft, wheel bearings, rear, etc., which makes sense since it is very noticeable when the car is sitting still running in park. The engine is an essentially stock rebuild of the original N code 383 mated to the original 727 trans. The trans was rebuilt by me and the torque converter is a refurbished stock 10 3/4 unit I got from Tflite Patty. I've run the engine with the PS and Alt/Fan/WP belts removed and the vibration remains the same. I replaced the harmonic balancer with a refurbished original one. It runs true without any wobble and did not make any change in the vibration. The engine has a stock flat tappet hydraulic cam from Mr. Sixpak with his lifters. There is one lifter that rattles a lot if the engine is not run for several weeks and takes a while to pump back up. The engine runs good, starts easy, runs cool, and has good power. I can see some shake in the engine at idle, but seems like what one would expect for that engine. I cannot feel the vibration in the engine like I can in the steering wheel. I pulled each plug wire while the engine was running about 1500 RPM and got about a 100 RPM drop on each cylinder. The drop varied some with 80 RPM being the least drop on #1 and on #5. I'm about out of ideas before I start diving into either the engine or transmission and then not sure where to begin. Thanks for any help or suggestions you can provide.
Regards,
John Brough
