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#1
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1992 400SE M119.971
Engine Dies After Cold Start on Accel./Decel. TSB: DDAF05_20-U-6400FA Date:01/27/1999 After much research into a dying engine, I pulled the valve covers to examine the Variable Valve Timing Actuators on the right & left intake camshafts. By cranking the engine by hand at the crankshaft nut strange clicking noises were coming from the right intake camshaft timing actuator as it spun. It was the signs that an indy told me were associated to a failing/failed timing actuator where it does not return to Retard Position quickly enough, thus essentially stalling the engine. I set the crank to 45 BTDC and went to lock the 4 camshafts. To my surprise I was only able to lock with the pins the Right Intake & Exhaust Camshafts & Left Intake Camshaft. The LEFT EXHAUST Camshaft is off as if it had jumped back a tooth or two (opposite of engine rotation). SEE ATTACHED PIC. I began examining the timing chain guide rails and found all intact (the top two between the camshafts came off without braking #6 & #16 in attached PDF). Further down I found the guide rail in the left/drivers side lower part of the block slightly snapped near the top end (#29 in attached PDF). The 3 camshafts locked in at approx. 38 degrees, which indicates 7 degrees of stretch. I’m looking for some opinions on how to proceed. The guide rail that’s broken requires the front timing cover to be removed ![]() I couldn’t snap a good picture showing the broken end, but it is a very small chip off the top end. How is it that the left exhaust camshaft sprocket jumped like that? The tension is very tights on the chain. Should I just reset the left exhaust camshaft so it locks with the pin and change the timing actuators which I have from a parts cars? |
#2
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Before doing anything! replace the chain & upper rails, also the guides between each of the cams!
If the chain jumps more than 2 teeth...the valves will be JUNK, and that is a 20+ hour job with $$$ in parts.
__________________
MERCEDES Benz Master Guild Technician (6 TIMES) ASE Master Technician Mercedes Benz Star Technician (2 times) 44 years foreign automotive repair 27 Years M.B. Shop foreman (dealer) MB technical information Specialist (15 years) 190E 2.3 16V ITS SCCA race car (sold) 1986 190E 2.3 16V 2.5 (sold) Retired Moderator |
#3
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Should the guide rail in the left/drivers side block #29 be replaced?
Since I would need to remove the front timing cover for that job I would also change the tensioner guide rail. If I proceed this route, should I change the timing chain with timing cover off instead of feeding it through? It appears the lower pan needs to be removed for that job and as such I would more than likely also change while in there: -oil chain -oil chain guide rail -oil pressure relief valve Any input to confirm or deny? Thanks |
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