240D Cam Timing/Possible tooth slip?
 

I just bought a 1981 240D, (my birth year car!) after selling my two previous MB's ('77 300D and '79 240D) about 6 months back. This new one is a beauty find for somewhere like Ontario where we don't get too many that are not full of holes.

First on my list was an oil change and valve adjustment, which I have done well over a dozen times before, but apparently I'm a little rusty, I was turning the engine backwards for a few valves before I realized. I've turned everything back proper (clockwise, which I think I'll never forget again) and adjusted all of the valves. Now when checking my cam timing by lining up the cam notches, my crank is retarded by about 6 degrees. I didn't check it before, was it likely set like this or Did I skip a tooth?

I have read all of the searches I can find on timing and cam timing and found mention of skipping a crank tooth equal to about 7 degrees....did this likely happen by cranking the engine backwards?

Is it an issue? How can I fix it?

I'm afraid to start the car!

Help much appreciated.

Thanks,

Will

PS....I was turning the engine over by the crankshaft nut and not the camshaft nut.

I believe is more like 18, but you need to check the IP timing. Your crank/cam timing is off 6 degrees which means its time for a new chain. If your IP timing is off it will be very hard to start, I would fire it up.

I had the car running after I bought it for a few days and it seems to run like a dream compared to my last two MB's when I picked them up.

FYI: Milage is 249,000 km (152,000 miles), I plan on doing the timing chain soon.

Thanks for the advice. I think I'll start it up.

I think allot of folks have turned the engine backwards before they found out it was a no no. ;) With 6 degrees of stretch I would think it possible to jump a tooth, but hopefully all will be well.

I still do not understand how this is possible. The chain tensioner has a locking mechanism that keeps it from retracting when there is no oil pressure. I can't imagine how enough slack is generated on either side to jump a tooth anywhere.

The ratcheting tensioner was introduced into production in a certain year I am unware of. Chances are it's chain stretch.

I don't believe any tensioners for the 616s are ratcheting.

7 degrees is worn but fine, throw an offset woodruff key in the cam gear and adjust the injection timing.