A Broken Crankshaft and Center Main Bearing

[TimK]

After being on the road for the past few months I finally got a chance to tear into my Burb and figure out what the hell went wrong with the engine. Right after Thanksgiving I was leaving the work site and the engine started getting really loud. By the time I got pulled over the engine was making one helluva racket. The closest way to descibe it is the sound of very big rocks in a very big blender. At first I thought it was the torque converter coming loose from the engine again but it wasn't.

I pulled the pan off this week end and I found 2 major fractures in the crankshaft on either side of the center main bearing. I also saw where the center main bearing was broken way from the block. I would most definitely say this engine is dead. With 250K miles on this engine I don't think I would even consider reusing the heads and installing a short block.

I have looked at some long block alternatives. Until I can save some cash and convince my wife on spending it, it appears the old Burb won't be going anywhere for awhile. If anyone has a running donar engine (cheap) let me know. I may be interested. On the otherhand, If someone is looking for a Heavy Duty (K-case)TH400 that was rebuilt 1500 miles ago, let me know. It's not doing me any good right now.

TimK

[CleviteKid]

Bad Luck, Tim ! !

Sorry about the engine deciding its time is up. One option to considered is a used, guaranteed (90 days) engine from The DIESEL DEPOT (http://www.thedieselpage.com/vendors/avant.htm).

And when you calm down enough to look at the old engine objectively, we would all like your assessment of the condition of the torsional damper on the front - had it deteriorated enough to break the crankshaft ? ?

Good Luck with a replacement,

Dr. Lee :cool:

[Ratau]

How do one do a assessment of the condition of the torsional damper as I am busy to replace the sprockets and chain with gears from DSG. The damper came off easy with a puller it was a light press fit and no damage on the crank or damper shaft area.

[CleviteKid]

Damper inspection:

You have done step one, pull it off the crankshaft.

Now, look carefully at the rubber layer between the hub where all the bolt holes are, and the heavy outer rim. The rubber should still be pliable, not cracked and hardened, and it should not be extruding outward anywhere, NOR should it be sucked in anywhere around the two surfaces you can see. The outer heavy rim should be firmly attached via the rubber to the inner hub.

If in doubt, replace it. Better than a broken crankshaft when you least expect it.

Dr. Lee :cool:

[cubby]

A bad damper got me last March. I had a rattle that I couldn't figure out. Then I found It was the damper. I replaced it. Apparently it was to late, a couple months after I replaced it, The Big Bang occured with no warning. It was an expensive mistake on a motor that was rebuilt only 2 years before its demise. I couldn't figure out what happened to that motor until I joined the DP.
With my confidense restored, and helpful hints form the wonderful members at the DP I have just finished a full restration of my 86 Chevy 1 ton 4x4 dually. Texas cab, sanblasted everything!!!, everything repainted with coal tar epoxy, rerouted brake lines, rebuilt 6.5 block with all of my 6.2 stuff bolted on, new trans, checked out np205, new springs/hangers front and rear all seperated sandblasted painted with coal tar, drive shafts rebuilt, all new brakes, the list go's on and on. Everytime I turn around, it's another 300.00 dollars. Every inch of this truck has been inspected, fixed,or replaced. I figure I owe it to my truck because it has plowed snow every year of its life, and I hope to still be plowing with it for another 15 years.
Sorry to ramble, I just love th DP. I am already starting my next 6.2 project, 85' 1 ton single axel, at least 250,000 miles, motor tired, will recieve the same treatment as the above.

Thanx Everyone

[gmctd]

You should enter your rig in the photo contest here.
Or make an e-album of them all with a link in your sig.
Rebuilt or restored '74 to '87 trucks are neat stuff.

[cubby]

I just got a digital camera for christmas. I'm planning on taking pictures of it before I put the front clip on. (tomarrow) We've been so busy plowing I hav'nt had a spare Two days to finish it. I have to by sunday night, so I can get exhaust on it.(supposed to snow monday night) I just lost 3rd gear in my 1 ton single axel that I've been plowing and salting with while I finish the dually. At least With pulling the trans I have a good excuse to put in my np205.