Jig for Adjusting Valves
by Scott Ashworth

My dad and I got together on Saturday to do some overdue maintenance on the TF. We contemplated a valve adjustment, which led us to talking about how to do the valve adjustment, which inevitably led to a discussion of designing a jig to do the adjustment. Yes, I have feeler gauges and even a Click Adjust. However, (and maybe it’s just my inexperience) it seems that my valves are pretty fiddly to get right. We got to thinking that using a dial indicator would be a good way to go. I checked the archives and didn’t see anything about a jig, although I did find one reference to a fellow who used one on an MGA with the indicator mounted on a set of adjustable rods mounted on a head bolt. So, fighting our tendency to over-complicate, I made the following jig which is really very simple. I used it last night to adjust the valves, and then because it was so easy to use, I checked the valves again after a long drive.
It really is simple. I use the two threaded rods that hold the valve cover to suspend a steel bar across the length of the engine above the intake manifold. With ¼” pipe, I made two spacers that fit over these rods. Because I did not want to remove the hood to do the job, the front spacer is in two pieces, each of which fits the clearance under the hood. Two short pieces of aluminum angle run from the rods to suspend the steel bar. Above these pieces are two spacers that run to within ¾” of the top of the rod so that I can use the knobs from the valve cover to hold the thing in place. These pieces are in the picture that I have attached to this post.
I made a sled for the dial indicator out of ceramic magnets, and put an adjustment at the mounting point so that I could get an angle that was close to that of the valve in the head. That will be in the post #2.
What is nice is you can set the sled next to #8 valve to see when it is fully open, then move it to #1 to set the gap, and then leave it there to do the reverse. I really like being able to see the exact amount of gap on the dial indicator. (You can go to the archives for all the discussion you want about the right amount of gap, but I used .012”.) The jig in use is in post #3.
It takes very little time to set-up, which is important because I am slow as molasses and always lose the race to the cooling engine. Isn’t it nice that MG provided us with a crank just to be able to adjust valves?
Once again over-thinking a simple task…..
Safety? Fast?
Scott Ashworth – ’54 TF with

Here is the magnetic sled for the dial indicator.

Here is the jig in use looking from the manifild side. I put a post in the back of the sled that keeps it registered to the right spot in the rocker.

From adjustment side

From the adjustment side - wider picture.
Good Luck.
Safety? Fast?
Scott Ashworth - '54 TF

insert content here