I need help identifying a part. I have a '90 300ce. I made the grave mistake of allowing an alleged mechanic do some simple engine work that resulted in some serious engine damage. After a lengthy period of time, and it never getting fixed, I had to remove my vehicle from his shop, along with a number of boxes of parts. I have a part that at first sight looks like a wood-ruff key, but with an end ground off and a notch on the flat side. I think that it must ratchet or index in operation. I do not know if it is associated with the timing chain tensioner. I can not find it in my manual or online. The approximate size is 10mm long, 5mm tall, 5mm thick. I can almost complete assembly and see no where this part should be. Also, there is a possibility, this fell into the box in his shop and is not related. But, I doubt it, and would be foolish to not seek help.

 

If you have a credit card with a US address on it, you can access Mercedes EPC here:
http://epc.startekinfo.com/epc/login.jsp

You can then look up your engine and find where this woodruff key may have came from.

 

This has not been subject to any 'hammer'. There are no impact marks. All sides still have casting/machining marks without dents, nicks or scratches. The flat side, at the tapered end, has slight abrasion marks from where it makes contact when it is in place. The notch/groove is perfectly symmetrical, shaped and positioned, it resembles the sears and pawls on parts that I would see on parts while doing gunsmith work. I have lined it up with the wood-ruff key that I have on the crankshaft and it exactly identical, except the flat end and the notch. This was formed by a shear or a shearing action. This has to be an intentional and deliberate part. I cannot believe this was caused by failure or an inept mechanic. It is too perfect. And, if a 'mechanic' caused this, at least one other part would be showing signs of force. I have attached another angle of view, and, I could provide some pictures, taken with my macro lens, that can show a more clear view.