I just noticed that there is a specific tool to assist in replacing the timing chain. Based on my research it seems like it's not necessary for the job, but it sure looks like it might helpful in keeping tension on the chain as you are rolling in a new chain.

Has anyone ever used one of these before and was it worth the extra help?

I have never used it, but some members have made their own version out of wood etc..

try searching under the 'Resources' tab.

Who is selling that tool? Peach?

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1984 W123 300D turbo
1989 SRW F-350 Reg. cab 4X4 &7.3 w/ Banks turbo
1993 Cherokee 2dr 2wd w/ 4.0 L6
2007 20ft Tiger car hauler trailer

I have a similar Klann tool design for the OM 60X engines, I have used it numerous times and it works excellent. The biggest advantage as I see it is that it allows me to roll a new chain into place without needing another person to assist. That can be done with tye wraps etc but these tools make it easy and quick. I get the original chain broken and connected to the new chain with a link, then I lay a plank off to the left hand side and stretch out the new chain on that, grasp the old chain with my left hand as it comes of the sprocket and turn the engine over using my right hand to operate the ratchet/socket on the crank bolt.

I stuff rags in around the sprocket to avoid loosing any parts down the timing chain chase. If you don't have a temporary link with clips to secure the link in place, I use a very small O-ring to tension the link in place. I put the pins of the link through the first half of the double chain, then with the second half links flipped up out of the way stretch the O-ring over those two pins, flip the links back down and push the pins fully through the second half of the double chain. The O-ring rides where the center link plate usually resides, it can't come off and it gives enough tension on the pins to keep the link in place as it's pulled through the engine.

I find the hardes't part of a timing chain R&R getting the center link plate forced onto the pins of the new link. Not much room to work in and you want to be careful you don't position that link too close to either half of the chain, it should be evenly centered in the space between the double chains not touching or binding against the side plates of either one.

I'm not sure what the tool costs but it makes the job quite a bit easier and less prone to a "skipped tooth" error so it will be worth it if you've got some extra cash to spend for "piece of mind"! Or you can always buy it, use it, and then sell it! Good luck!