I am recovering from the cracked head syndrome while I wait for Metric Motors in CA to build up a new one for me. I decided to replace everything above the pistons. The precambers were rusted into the head on three cylinders due to water injection. So all new valves, lifters and prechambers. Much to the dismay of my checking account, I decided to also replace the cam, injectors, glow plugs, and fuel lines. Meanwhile, I am fixing a few things here and there while I wait for the new head. I've replaced the vacuum pump (due to recent threads on the subject) and the aux water pump. The timing chain is 10,000 miles new and has no stretch. However, I noticed that the lower rail has small cracks or fractures in the plastic. It also has groves formed by the chain that are about 1mm deep. I would like to think I could let this go, because the procedure to change it looks somewhat complicated. I would appreciated any insight.

If I have to replace it, I have a few questions that I was hoping someone could answer. With the head off, I am afraid to move the crankshaft even a little. How can I remove the Hub bolt without moving the crank? I have searched the forums and there was mention of pulling the starter and doing something to freeze the crankshaft but it was not clear. Is this necessary, or is there an easier way. Should I wait until I have the head and timing chain back on to attempt this? The manual also talks about lifting the engine to gain access to the bottom bolts for the timing cover. Is this really necessary? I have the front bumber and radiator removed and it seems I have ready access to all the hex bolts. Has anyone had experience with this?

Also, I might as well replace the front crankshaft seal while I have the timing cover off. Is this something that can be accomplished without special tools? I read some threads which talked about R&R of the seal with the timing cover attached. Seems like it would even be easier with the timing cover off the engine. The seal does seat in the timing cover doesn't it?

I would appreciate any responses. It seems I am now in restoration mode of my newly acquired 1987 300SDL. I wouldn't even attempt it without this forum, although my wife still thinks I am nuts. Thanks.