Here is the information on John Walkers do-it-yourself timing chain tensioner tool. If you have any questions, or run into any problems, feel free to contact me by E-mail:

Ray Livingston


I'll be happy to provide whatever assistance I can.

This information is provided as a courtesy only, and on a strictly AS-IS basis. USE THIS INFORMATION STRICTLY AT YOUR OWN RISK!! I will accept absolutely no responsibility or liability for anything that happens as a result of your use of the information presented here.

John Walker has come up with what I think is a very clever way to build your own tool for tensioning the upper timing chain of any XK engine. This tool is fabricated using only hardware available from any local hardware store for just a few dollars, and simple hand tools. Given that most of the commercially available tools these days seem to be of very poor quality (mine
required significant modification before it could be used), making your own seems like a great way to go.


  • 3 1-1/2" OD fender washers.
  • 1 3/8-16 or 3/8-24 X 1/2" bolts
  • 1 3/8-16 or 3/8-24 nut
  • 2 3/16-24 X ¾ bolts, preferably stainless steel
  • 2 3/16-24 nuts, preferably stainless steel

All the above materials should be available from any good hardware store or home center (Home Depot, Lowes, etc.). Stainless steel is preferred for the two 3/16 bolts, for extra strength, though plain steel can be used.

An assembly drawing of the tool is show below. Basically, the fender washers are used as a mounting plate for the two 3/16 screws, which are spaced such that they will fit into the two holes in the tensioner adjusting plate of the XK engine. The 3/18 bolt both holds the stack of fender washers together, and also provides a means of easily turning the tensioner, by means of
a standard socket wrench.

First, Insert the 3/8 X1/2" bolt through the center hole of all three fender washers as shown. Be sure the bolt is centered in the washers. Use locktite on the threads and tighten the nut onto the bolt securely. 

Grind, saw, or file the head of the center bolt down until it is about 1/8 inch thick.

Drill two 3/16 dia. holes 180 degrees from each other exactly 1-5/16 inch apart (center to center).

Insert one 3/16 X 3/4" bolts through each of the holes you just drilled. Make sure the bolt heads are on the same side of the fender washers as the nut of the center bolt. Secure each of these bolts with a nut.

If necessary, slightly file down the last 1/4" of each of the 3/16" bolts so they slide easilyinto the adjuster holes.

The beauty of this tool is that you can adjust the chain tension with a socket wrench and a 9/16" socket.