Timing chain off crank-please help! - PeachParts Mercedes-Benz Forum

tomawilson · #1 03-31-2008, 09:41 PM

Hi guys, I'm a noob

and I didn't get the timing chain secure after taking off the cams. How do I fix this? I find a lot of info about replacing the chain by following the old chain but no info if you have no clue where it should be. I noticed there are 2 other sprockets besides the crank, are those crucial as to the position as well

Its a 85 500SEL M117.963 Sorry for the long post.
Thanks guys!

Johnhef · #2 04-01-2008, 08:33 PM

What exactly do you mean by off the crank? part of the front cover holds the chain in its place on the crank when the chain is off of the cams.

Tomguy · #3 04-01-2008, 11:04 PM

If you are sure your cams are far beyond alignment, and don't recall the original alignment, there's only one thing you can do at this point. You're going to have to install the chain as is, after removing all the rocker arms (to ensure there is no valve/piston interference), and calibrate the timing. Make sure you know which rocker arm goes where for proper re-installation to minimize uneven cam wear.

1) Turn the engine to TDC for the #1 cylinder as indicated by the marking on the hub.
2) Check the mark for the driver's side camshaft. Disconnect the chain from the sprocket and rotate the camshaft to TDC if it is not already. Reattach the chain to the sprocket, and turn the engine another 2 full revolutions (720°) to TDC - if you pass the mark, do NOT turn the engine backwards but rather go forward another 2 revolutions. Ensure it's aligned properly, and if not, reallign and re-check until it's spot on, or within 3° assuming new rails and a new chain.
3) Repeat step 2 for the passenger side camshaft.
4) Making sure the engine is still at TDC, remove the distributor cap and ensure the rotor is within 10° of the TDC marking on the distributor, and if not, remove the distributor, rotate the rotor into position, and re-install. Adjust until the timing is as close as possible.
5) Re-install all 16 rocker arms. To make life easier you can rotate the engine forwards while doing this so you do not need a spring compressor.
6) Start the engine, set the ignition timing. If engine timing is not close enough, time while cranking, then time once fired.

wbain5280 · #4 04-02-2008, 03:18 AM

If you mean that the chain has decended into the front area, but not fallen in, just pull up. The only issue will be the the distributor alignment. There is a small notch on the flange for TDC.

Make sure all the marks line up, cam notches and crankshaft.

Take some pics and let us know.

tomawilson · #5 04-07-2008, 10:49 PM

Thanks for the help guys, only the topside was out of position. The chain was still on the crank. I had marked the chain and cams so I'm just going to replace the chain after I put the old chain back in the original position.

Johnhef · #6 04-07-2008, 11:24 PM

crisis averted, good job.