Ever seen a 617 engine jump time?

I finally really got down to business with my daughters car.

To make a long story short, it was showing compression readings in the 100 PSI area. This is an engine that had 300 PSI in all cylinders just a few thousand miles ago.

I pulled the valve cover to adjust valves and check cam timing. The cam is severely retarded, at least one tooth, maybe two.

This seems to be an almost impossible thing to happen with this engine.

Could it be that the tensioner went completely slack and caused this when she shut it off?

I would appreciate anyone sharing any experiences you may have seen like this.

Thanks in advance,

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Larry Bible
'01 C Class, Six Speed
'84 Euro 240D, manual, 533K miles
'88 300E 5 Speed
'81 300D Daughter's Car
Over 800,000 miles in
Mercedes automobiles

Larry, I have worked on MB diesels since 1967 and have never seen one "jump" time. I have seen a few break chains but never jump a link. There is no room for the chain to jump a link as it travels around the engine. Especialy at the injection timer gear and crankshaft gear not to mention the wee spaces at the chain guides. If the chain tries to jump a link, something has to give and it is usually the chain. Now if one of the Woodruff keys(cam or crankshaft), gets sheared off, well thats a different story.
Please let us know what you find out.
Bill Lewallen Lexington,Ky.

Bill,

Thanks for the response. The woodruff key sounds like something that could happen. I could not see how the chain could possibly jump like it might on an American car. The only possibility I could come up with was the tensioner going limp and somehow causing this to happen.

I'm going to go out there right now to see what I can find. It's warmed up a little. If I wait until the morning, I'll freeze. There's too much diesel fuel all over the place out there now for me to be safe lighting my propane heater.

Thanks and I'll report back later,

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Larry Bible
'01 C Class, Six Speed
'84 Euro 240D, manual, 533K miles
'88 300E 5 Speed
'81 300D Daughter's Car
Over 800,000 miles in
Mercedes automobiles

Larry, I know your daughter's car is giving you fits, but don't despair you will solve the problem
The last 617.952 engine that I rebuilt had on off-set on the crankshaft that was wallowed out(us Kentuckians say wallered). I replaced it with the right key and welded it in with JB Weld. With 200+pounds of torque on the 27mm. bolt holding the vibration damper against it, I don't think it will move. This is the engine that I rebuilt the turbo. Cost for turbo parts;$22.63. Who says you can't rebuild the turbos?
They (turbos)are made in the USA. Mine was a Garrett.

[engatwork]

I have seen a lot of folks in south Ga. broke down by the road with a car that would not run because they said it had "jumped time". They were still sitting there by the road broke down when I pulled off. I have given a few of them a ride home though.
good luck
engatwork
'95 E320
'97 Honda CRV

[Benzmac]

I have seen them jump when the vacuum pump comes apart. This will cause pieces to get into the area below the cam where the chain goes around the pump and crank.

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Benzmac:
Donnie Drummonds
300E
ASE CERTIFIED MASTER AUTO TECHNICIAN
MERCEDES SPECIALIST 8 YRS
PARTNER IN MERCEDESSHOP.COM
OWNER OF MB AUTOWERKS .COM

Thanks for the responses.

Benzmac,

What you sounds the most plausible, I will pull the vac pump as the second step of my exploratory surgery. It sounds like if something has jumped at the bottom sprocket, I need to check the vac pump anyway.

I checked the cam sprocket yesterday and all's well.

Please keep the experiences coming, and I will keep everyone posted.

One of the scariest things is disturging the harmonic balancer after reading all the harmonic balancer nightmares that I've seen here.

Thanks to everyone,

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Larry Bible
'01 C Class, Six Speed
'84 Euro 240D, manual, 533K miles
'88 300E 5 Speed
'81 300D Daughter's Car
Over 800,000 miles in
Mercedes automobiles