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?

Attached Thumbnails

       

Attached Files

M119.971.pdf (78.7 KB, 192 views)