Clutch/flywheel balancing 195.6

Hello all:

Long story short: I had the clutch disc replaced on my '60 Rambler (in the avatar), while the shop was at it they put in a rebuilt pressure plate assembly and machined the flywheel (along w/throwout bearing & bushing, a whole kit in other words.) Now it feels like there's driveline vibration that I didn't have before...it's strange, the engine seems to idle very smoothly but inside the car there's considerable vibration. Now: there just isn't that much in there, I saw the parts that went in, and I don't see how any of those parts would throw the balance off so badly. I will mention here that they were afraid to take the rear suspension apart because they were afraid of rusty bolts breaking off inside the body, so they pulled the engine out to do the job. Could something have happened to the harmonic balancer when they took the engine out? Or could something have been reassembled 90 degrees off or something? I'm looking for things to check before having it all taken apart again.

CN

if the harmonic balancer is original, or very old, they do fail, the rubber between them rots, and the outer part rotates relative to the inner, bolt-on part. not sure if you'd want to suspect it, as joe says, but it's easy to check: check timing with a timing light. the mark/notch is on the pulley half of the balancer, a sure sign that it's rotated is the timing mark is in some crazy place.

The first thing to come to mind is motor mounts. That engine uses four motor mounts -- two in front and two on bell housing. Make sure they are tight and not damaged. IIRC they are flat "puck" type, and can separate and be hard to spot.

FWIW I replaced the front motor mounts in 2015, so I know they're okay...the rear motor mounts are actually on the transmission itself and haven't been changed, and are not available new. Remember that the auto trans uses four of the puck-style motor mounts, the standard trans uses two pucks in front and a more complicated square style in back. Given that they didn't want to take things apart in back, it's possible that they loosened them and didn't tighten them back up correctly. 

Not sure, it just seems so disproportionate from what I see in the engine compartment to what I observe inside. Around 50 mph in third seems to be a bad spot, but it's been my experience that lots of engines have certain points where there's more vibration than at other RPMs. By all means, however, I'm going to check everything for other possible causes of engine roughness. I will say that it sounds like the valves need to be adjusted as they're getting pretty clacky, even though I did that about 4,000 miles ago. But within that 4,000 miles was a trip to Colorado where the car got a workout as it hadn't had in decades.