Engine/Transmission (1998.5 - 2002) Timing has Changed?

[DThibault]

I finally have the 2001 HO engine apart where I can see all the timing marks, the pistons and even took the cam out part way. I bought the truck as is with very little history. Reportedly it was idling on the coldest day last winter with no one around and when the driver returned it was dead. A mechanic glanced at it and most of the pushrods were bent and therefore no compression. I bought it and took the front cover off and removed the head. There is very little signs of contact but one can see faint marks in the carbon where the valves did hit the pistons. The head is at the machine shop for inspection. All the gears under the front cover look healthy and the dowel pin is in place, and when I line up all the timing marks to TDC, the No. 1 and No. 6 pistons are at the top of their travel. The alignment pin on the crankshaft looks to be intact. I slid the cam out enough to see the first lobe and it is pointing straight up as if to open the valve. That does not seem correct to me as when the engine is TDC both valves should be closed. I did try to turn the gear on the cam by hand but it did not turn with the torque I put on it with oily hands. Any ideas? Am I missing something?

Has anyone ever heard of the timing moving on a Cummins? Thanks

 

[JMetzger]

I am sure that there is a key in the cam for the gear so that it will be in time. Try taking the gear off of the camshaft to see if key sheared. If that happened I really don't know what happened unless you had #6 as TDC instead of #1

 

[Vaughn MacKenzie]

If you were one engine revolution off both the intake and exhaust lobes of #1 will be right on the edge of the opening point, definitely not straight up. . . the only time a lobe will be straight up is when the piston is halfway down the bore.

 

[DThibault]

thanks, I'll yank the cam out and see what the damage is. Very strange unless I didn't get the whole story about the failure. Doesn't matter, I'll fix it and drive it.

 

[DThibault]

Pulled the cam and the third journal in had seized enough to evidently allow the gear to turn, I haven't taken that off yet. Now, I have to find out why. Maybe the oil passage holes weren't lined up all the way and the cold morning thick oil didn't do the trick. All the others seem fine.

 

[Bob4x4]

You do know that cam bores 2-7 do not have bushings right?

 

[DThibault]

No, I did not, what could have scored the cam up? How is it supported in the middle? It looks like a badly seized journal. I have not pulled the gear off yet, I need another rainy day so I can hide in the shop. Very weird situation so far. Any help is appreciated.