What's the basis for this conclusion, other than the desire to sell more parts?

And, what about the tensioning rail........does he make mention of this component?? If you are going to do the chain and the tensioner, does it make any sense to ignore the tensioning rail?

I did take a close look at the rail but it really did not appear to have much wear. All things considered, it looks quite smooth and even. Wouldn't the chain wear a trench of sorts in that rail?

I really am thinking the chain and rail and upper guide may have been replaced before I bought the car.

I just want to PREVENT a problem, but do not want to pay to do unecessary maintenance. But I do not want a catastophic failure either.

Thanks for letting me know about the valves versus stretch issue.

The first time I lined up the marks on the cam washer and read the balancer, the mark between the upside down 1 and zero fell right in the middle of the marker tip on the block. I guess that would mean 1/2 to 1 degree of stretch?

The second time, it fell on the counterclockwise edge which someone already said meant no stretch.

That is still well within standards and may mean that the former owner had it replaced. His mechanic had purged his records as had the owner but the mechanic said he did whatever was needed to the car. The mechanic said he had considered buying the car very seriously but didn't have the cash at the time.

__________________
1982 300SD Light Blue
2002 Honda Accord SE
1974 Toro Wheel Horse Tractor
2000 Toyota Tundra Pickup

You can't determine how much wear is in the tensioning rail because the chain is in the way. You need to remove the tensioner and then remove the chain to carefully inspect the tensioning rail. Anyone who believes that they can do a proper inspection with the chain in place is kidding themselves.

The chain, clearly, has no wear. It more than likely has been replaced, however, the SD currently reads 2.5° on the balancer using the tower marks and I'd doubt that it was ever replaced. So, you really never know.

Here is a qoute from the ************** web site regarding the timing chain, etc (emphasis added):

This is a super important maintenance item for your diesel engine. Depending on maintenance and oil change schedules this chain should be replaced in the 150,000 mile to 200,000 range. If your timing chain lets go while driving, it is not a pretty sight. It will usually destroy the engine. If the chain is stretched more than 3 or 4 degrees your cam timing and injection pump timing with be retarded. This will lead to rough starts, excessive smoke, and poor power.

As well as the chain I always replace the timing chain tensioner and upper chain guide at the same time. By replacing this you will be pleased with the new performance as well as sleep better at night.

Notice he makes no mention of the tensioning rail, the item that suffers the most wear. I presume that he means the "upper chain guide" is the slide rail in the head. This item is relatively easy to change but it suffers little wear.

As for the chain itself, we've discussed it to death, but, if the chain is not overly elongated (6 degrees or more IMHO), it serves no purpose to change it just becuse it has reached 200K, with the sole benefit being the enrichment of Mr. Bergsma's bank account.