1948 Buick Roadmaster Harmonic Balancer Causes Engine to seize Up??

[Guest Caddy Guy]

I just inherited my dads 1948 Buick Road master Sedanete,it is in great shape and was running great! I went to start it today and it turned over then all of the sudden a loud banging noise happened and it stopped turning over. I looked and felt where the pully is and you can move it side to side where the harmonic balancer is attached,very loose. The harmonic balancer was tumbling hard when it would idle so Im not sure if that caused the car to sieze or what,how far up the creek am I??? Its a straight 8 with the Dynaflow. Any help would be appreciated and I can answer any questions. Thanks in advance!!

[Pete Phillips]

I dont' understand what "tumbling hard" is in relation to a harmonic balancer. Had the engine been sitting up unused for many years before you started it? I know you said it was running great, but how long ago? I've never heard of a straight eight crankshaft breaking, but that's almost what this sounds like.

Pete Phillips, BCA #7338

[1939_Buick]

The other thread on the same topic http://forums.aaca.org/f165/1948-buick-roadmaster-harmonic-balancer-causes-350089.html

Can a moderator move & merge ?

[Guest Caddy Guy]

Thanks for the response you guys. It wasn't running at all when this happened, I was giving her a bath and went to start her so I could finish cleaning the rear white walls,and as I started it the motor turned over and then it thumped hard and the belt stopped turning. I felt the harmonic balancer/bottom Pulley and you can shake the bottom pulley cause it is loose,the belt never broke. If it is the bottom pulley that broke off at the crank, is that something that can be fixed with out pulling the motor?? I will check the starter in the morning to see if that is the problem but I dont think that is it, and I may have jumped the gun by saying it was seized up with out knowing more first! I was heart broken cause she was running great and the car is in beautiful shape and was my dads daily driver until he passed away a few weeks ago. Just got back with it from Winslow AZ yesterday. Thanks for the help, I appreciate it!! And Pete, I meant that the bottom pulley was shaking on regular idle while the car was running,tumbling like it wasn't balanced.

[old-tank]

Pull the plugs and try cranking...might be water in a cylinder.

[tom_in_nh]

It is possible that the harmonic dampener separated at the rubber. It is safe to assume that the timing chain did not break.

[Guest Caddy Guy]

Do I need to pull the motor to check? Or can I just pull out the radiator etc to get to that bottom pulley? I have worked on quite a few motors since I was a kid but this is going to be my first run with a straight 8, I noticed there are bolts on the front of the motor behind that pulley attached to a plate as well. trying to be careful so i don't mess anything up in this process. Thanks for the help!