Broken cam? How??

[Mark Nixon]

Picked up a '90 1 tonner this past weekend that was supposed have a broken crank, got there and found it was actually the cam that's broken, which is probably a better scenario.

I'm curious as to how this can even happen, as the dowel pin is still where it should be and none of the internal case bolts are missing.
It does show signs of some sort of gear damage, but I can't for the life of me figure what would have gotten into the gear train to break the cam.

The history I was given is that he'd had an injection pump done on it, and it definitely HAS been changed, then drove it until it just all at once broke the cam one day.
Is a cam breaking out of the blue a Cummins problem, or must there have been some sort of interference in the gear train for this to happen?

Mark.

[BC847]

This would be the second time for a 1st gen in reading these and other forums over the past five years.

[dpuckett]

Seems like it was a D350 I read about. About a year or so ago. Could be the same one, could be different. Why? I dont know. I'd say find another nonIC cam, check out the engine for other damage, and stick it in there.

Dan

[burnt_servo]

where did it break the cam ?

[Oddfire]

where did it break the cam ?

X2

[Philip]

Check and see if the key is still in that injection pump drive gear.

[BobS]

Check closely to see if it is missing any of the cam retaining bolts or timing case bolts.

[PToombs]

Something had to go thru it. Cams on these engines don't just break. If they did, with the number of these engines out there, we'd hear about it alot more often than we do.

[Gen 1/2]

Check the valves. I rebuilt my motor 8 months ago because my cam broke right in side the motor right behind the berring it also bent the push tubes.

[Mark Nixon]

It broke the cam right between the first lobe and the front cam journal, it didn't even damage the bearing.

dpuckett, it's probably the same truck, I got it out of Sanger, Texas.

I did take a quick, but closer look at it earlier to-day, then had to go help a bud with his '03 Dodge, he had a lift pump go out on it and it hadn't been updated.
At least HIS was easy. Maybe. We'll see if he loses the injection pump soon.

Whatever went through this enginein the'90, it trashed the bearings in the injection pump, and the vac/power steering pump, because they are extremely sloppy in shaft play.
Didn't think of the key in the pump gear, will take it apart and look to-morrow.
Will look at valve adjustment, too.

Mark.

[Philip]

Mark when you get the broken cam out. I want it. I want to check it against an IC cam to see what the difference is between them.

[dpuckett]

Philip- report back to us. I need to know if a nonIC cam would be worth the money when I change gear housings. Though a goodly dose of silicone is holding the oil in check for the moment.....

Mark- I have a parts VE pump I can sell you. But, my mom's pump has 30K or so on a rebuild, and it has some slack in the main shaft, too. Not sure what that means- maybe needs shims for the return springs? KTA- what's your take?

[Mark Nixon]

I figured it out.
The last owner was right, but then that proves he probably doesn't listen to noises in his vehicles.

The vacuum pump bearing apparently locked up, spun the race in the pump case and sent the ball bearings into the gear train, which to me is some VERY severe lack of attention.
It HAD to make some odd noises in the engine, even while idling, as loose as it is, plus the fact that the race bangs and clangs around on the vacuum pump shaft.

Destroyed in the process:
BOTH vacuum pump AND power steering pump (Cracked P.S. case stem).
Cam and cam gear.
Injection pump gear, possibly injection pump.
Possible crank gear, can't see it all from the top.
Gear case is cracked, possibly a patch for leakage will fix.

I was running the engine in the '90 4x4 I bought out of Kentucky to-day, (The one I'm parting out) and noticed it has an unusual thunking noise in the front case area on the driver's side, any bets on if I pull the pump and it's getting ready to do the same thing?
Figures, I just sold an extra '92 pump assembly I had here.

I'm not too sure WHAT I'm going to do with this thing, the thought is there to part the whole deal out and use some of it on the re-birth of my irritating Carhauler, of which I STILL need to do a re-power and re-body.

If it runs, it ain't broke, right?

I may have pulltilbroke come over and asess the I/P for me, possibly can re-use it on the other engine in the 4x4, since it's extremely high miles and never been touched.

PHILLIP, If I get that far, you can have the 2-piece cam, just pay shipping and take BOTH pieces.

dpuckett, may very well be interested in the parts VE, depending on what pullit says.

Mark.

[KTA]

Daniel there is a bushing/thrust deal in the vane pump area of the injection pump that has to be replaced when it starts getting sloppy. I know of 2 cams that were broken by people dropping the pump key and thinking it would be alright to just put another in and go on. Wrong answer!

[dpuckett]

This is in-out, not up and down slack. It is tight side-side/ up and down.

DP