I got a 1884 380 SE and the timing belt has jumped. What are the after effects of it jumping? Is it likely that the valves are bent now or couldv'e gotten bent?

Well,TOPCOW if the motor still cranks and run it's a
good thing.But if doesnt it's a grim thing.I've seen
alot major engine damage when the (CHAIN)breaks.Depending
when the jumping or breakage happened at 70mph or turning
it over for first start in the morning.If it still runs
but more than likely poorly,you may be safe and POSSIBLE
no major damage occured.I would suggest you take to a
good dealership or garage and have them check it out.
either way it will not be a inexpensive repair.





GOOD LUCK

P.A.RONDEAU

20 YRS. M&B EXP.

No belts. Just a chain and its amazing how you will have only bent the valves on the left bank.

Let us know if you have a special case but in the two or three hundred my shop has repaired less than ten were any different.

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Steve Brotherton
Continental Imports
Gainesville FL
Bosch Master, ASE Master, L1
33 years MB technician

Paul, whats TOPCOW mean?
The 380's are famous (or infamous, as the case may be) for unreliable timing chains, as they were ex-factory with single-row chains. Updates to double-roller are commonly executed. If the chain jumped at start-up, you may be OK as far as further engine damage. For cripes sake don't drive it if it runs, don't even crank it. Get it in and get it changed over, as a good dealer would have recommended a good 10 years ago, after the problem was apparent. Jumps at speed are know to cause damage, including, but not limited to, holy pistons, pretzel shaped valve stems, and ventilated valve covers and blocks.
Gilly

Thanks Very Much

I am 18 and my parents benz timing chain jumped at start up in the morning and I recently bought one from a auction with a jumped chain. BTW my parents benz had a rough idle he changed the idle box (black one against the firewall.) and when the O2 sensor was disconnected it works fine we even replaced with a new one and it worked fine for a bit then went to rough idling... any ideas?

As for my nick.. just means top of the crowd... but its a nick from while back

Paul: I thought you were using an acronym of some sort, didn't see that TOPCOW was original posters handle. I just had a little brain fade (kind of like brake fade, but doesn't smell as bad).
TOPCOW:
What did you buy at auction, a whole car or a motor with a jumped chain? If your parents car jumped at start-up, hopefully it is a simple chain and gear update. I have done a couple that were OK, but unless the owner is willing to pay for a motor tear-down, there is no guarantee that bendable bits didn't get bent. Ya pays yer money and ya takes yer chances.
On the rough idle, that doesn't make alot of sense in a few different ways. Mainly, the idle control module controls how fast the motor idles by adusting the frequency of the idle valve. It doesn't really have much to do with how smoothly the engine runs. By disconnecting the O2 sensor I believe the Lambda would go to 50% fixed operating mode. Maybe this is running the mixture closer to where it runs smooth, but not where it should be for emissions and so forth. I would begin to suspect something amiss in mixture preparation, not sure if it's driving rich or lean, common suspects would be a vacuum leak, bad injector or fuel distributor, or air flow sensor. Best bet would be to get it to a shop so they can inspect the Lambda control with the O2 sensor hooked up and see if it's driving rich or lean and go from there.
Gilly

Topcow,

The 84 already has a double chain. What you most likely have is bent valves on the left bank;it's a classic.What happens is the chain stretches past the limits of the chain tensioner because of extended oil change intervals or high mileage.The chains starts to whip until it breaks off the chain rail in the left head.The broken rail then lodges between the chain and the left bank sprocket causing it to skip and bend the valves.The right bank is usually not affected.Adding to this is poor design on the part of Mercedes;it seems they chose to screw steel head bolts into aluminum.Now the repair will require helicoils which should have been installed at the factory.

Peter

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