I have a 57 Tbird with a 312/Fordomatic.

I have an engine vibration that is bad at around 1300 rpm. Anything below or above this rpm is significantly less but still there. It is not driveline rated as it does it even in park or neutral. The car idles very smooth and quiet and runs nicely. I have noticed it is more noticeable now after replacing the rear motor mount.



Thanks

could be just engine harmonics at those revs my 272 does it as well

moz. geelong victoria australia.

graduate 1980, bus, truck, car, hot rod, boat, submarine, hovercraft, hydrafoil, firetruck, mobile home, jet, helicopter, cruise ship, motorcycle, bicycle, santa's sleigh, clock, alloy bullbar, alloy fuel tank, lens, dr who's tardis, matter - anti matter warp drive buffer & y-block lover

Nick.

      Two things come to mind, check to make certain the damper is in good shape, and all the bolts on the flywheel/flex plate are tight and in place.

Frank/Rebop

Bristol, In ( by Elkhart) 

Auto or standard? I bought a new pressure plate from NAPA come from China and it took quite a chunk of metal to balance it at the balancing shop

55 Vicky & customline

58 Rack Dump, 55 F350 yard truck, 57 F100

59 & 61 P 400's, 58 F100 custom cab, 69 F100, 79 F150, 82 F600 ramp truck, 90 mustang conv 7 up, 94 Mustang, Should I continue?

Could it be exhaust is causing vibration among other suggestions.

  AussieBill            YYYY    Forever Y Block     YYYY

 Down Under, Australia

check the steady rests on the sides. They do break

54 Victoria 312;  48 Ford Conv 302, 56 Bird 312
Forever Ford
Midland Park, NJ

You can try disconnecting the vacuum advance to the distributor and see if the engine vibration goes away.  I’m assuming this is a ‘shutter’ or vibration that only occurs when the engine is in neutral and is being revved up?  If the vibration goes away with the vacuum advance disconnected, then it’s simply too much advance without any load on the engine.  If unhooking the distributor vacuum advance doesn't alleviate the problem, then disconnect all the front belts from the lower crankshaft pulley and see if that makes a difference.

Lorena, Texas (South of Waco)

I have a '56 Thunderbird (312/Fordomatic) that has the same m-o. Only mine starts at ~1,900 rpms and smooths back out at ~2,200 while moving, or in park/neutral. I worried about it, checked what my limited skills could think of to check, and eventually I decided to just drive it.  It's still there, but I'm not losing any more sleep over it. (At least until it gets louder or longer)

pops (AKA) Clay

'56 Thunderbird

I had same thought as Ted, but in the opposite direction...I had a similar problem, and recently put in softer advance springs in the distributor.  Problem was significantly lessened.

Ron Grove

Wauconda, IL

The vibration is there in park or neutral and you feel it when driving. Luckily its a low RPM and felt only when accelerating from a stop. Once out of that range it is much better. I took off the 6 bladed fan. Still no better. May an engine harmonics issue?