1955 312 Engine shake

[mechanicboy]

A buddy of mine has a 1955 Thunderbird and claims it's a 312 Y-block (which from what I find can't be the original engine) that's freshly rebuilt and fully restored with only 13 miles on it. He claims not to drive it because the engine shakes. Unfortunately he wasn't about to start it as the battery was completely done after sitting for a year. My question is, are these internally balanced? If they are is the only remedy to rebuild and re-balance the rotating assembly?
Thanks.

 

[Steve@Tasca]

I'm not an expert on Y-blocks by any means and I honestly doubt you'll find any here but before you guys jump in to a tear down the first thing to do would be to verify that everything is currently correct as far as plug wires/firing order, cam timing, ignition timing etc.

Just did a quick internet search and found this book as well, try this link http://books.google.com/books?id=I7...e&q=ford y block internally balanced?&f=false

-Steve

 

[mechanicboy]

I'm not an expert on Y-blocks by any means and I honestly doubt you'll find any here but before you guys jump in to a tear down the first thing to do would be to verify that everything is currently correct as far as plug wires/firing order, cam timing, ignition timing etc.

Just did a quick internet search and found this book as well, try this link http://books.google.com/books?id=I7...e&q=ford y block internally balanced?&f=false

-Steve

Very nice, I missed that somehow but looks very useful. I'll be reading that when I have a chance.

I finally was able to hear it run and it had a random misfire while warming while warming up that needs to be sorted out. This went away when it was fully warmed up. The engine itself doesn't seem to shake much at all visually and by placing your hands on the valve covers but there's so much vibration transferred to the passenger compartment that he won't drive it. I noticed that the engine side stabilizers (can't remember the proper term for them) feel like they are made of hard polyurethane like compound and I would expect a rubber unit on a car like that. Maybe that's transferring more vibration to the passenger compartment than it should.

The carb does have a slight leak that is dripping a small amount of fuel down into the secondaries.

I told him that before we pull the engine we could at least fix that, pull the valve covers and check the valvetrain, a compression and a leakdown test. From sitting in the drivers seat it feels like it has a bent rod that's worst around 2k rpm.

Also note that the fuel is of unknown age, I just know that the car hasn't moved in over a year.

 

[Steve@Tasca]

Modern fuels don't hold up all that well over time without a stabilizer so fresh gas might help. I wonder if the torque convertor is out of balance or bolted on wrong, I've seen that before even though they're only supposed to bolt on one way.

I'd also expect rubber engine mounts, I have no idea how smooth a Y block should run but I know rubber vs urethane mounts is a massive difference.

-Steve

 

[mechanicboy]

Modern fuels don't hold up all that well over time without a stabilizer so fresh gas might help. I wonder if the torque convertor is out of balance or bolted on wrong, I've seen that before even though they're only supposed to bolt on one way.

I'd also expect rubber engine mounts, I have no idea how smooth a Y block should run but I know rubber vs urethane mounts is a massive difference.

-Steve

It is a stick shift and he had the clutch and flywheel replaced because he was told it could be shattered which would cause the unbalance. It's wasn't shattered though.

 

[Steve@Tasca]

Could also be an issue with the flywheel or clutch, could be any number of things though, that's the fun part.

-Steve