MTFCA Forum

Last week I started a thread that related to the 13/16" gap for the clutch spring.
Mine was tightened so the gap was way over an inch, close to 1.25".
A few readers gave some suggestions which I tried but still had a bad vibration around 30mph.
I decided to go ahead and see what was involved in replacing it with the engine in the car.
Ordered a new one and gave it a try. Took some creative thinking and two of us making stuff up on the go.
We did manage to get it out and put the new one in. Adjusted all the fingers so the gap was set
to the recommended 13/16". I have attached a photo of new and old. The overall length of the old one
was down to 2.5 inches. I am sure it is probably the original spring. You can see the difference in old and new.
We had some crazy vibrations around 30 mph so kept it under that prior to the change but I would say now that
the vibration has been reduced about 60% and the car is now drivable at 35+ mph.
Would it have been the clutch plates causing the vibration because of the old spring length?
I have read that if you have your engine out just go ahead and replace the spring which I did not do.
It would be a lot easier out of the car.

The test for the spring is to compress it on a scale to 2.00". Should read 90#
However, a spring that is that short is suspicious before the scale test.

The Ford service manual has several paragraphs about replacing the clutch spring with out pulling the engine which are very helpful. But with that said it’s easier to do with the engine out of the car especially when going an engine rebuild.

The two things that sometimes get overlooked when doing an engine rebuild are the clutch spring and the magneto coil ring. The engine block work itself becomes the main thing to do and the rest unintentialy overlooked.
And the clutch spring becomes the center of attention when you get it all back together and find that the engine runs great but the car won’t go like it should!!

There is really not much associated with the clutch that contributes to the vibration you're feeling. Here's a few easy things to check for that may cause vibration.

1. Missing the side wood blocks between your motor mounts and the frame.
2. Out of balance fan blade. (Surprising how much vibration can come from this. Try running with the fan belt off as a test.)
3. Worn out 4th main bearing. (Hopefully you checked this during your spring replacement.)

Hey Jerry, thanks for the suggestions. The only thing we did was replace the spring and a lot of the initial vibration went away. Could the 4th main have been a bit out of alignment during the initial assemble? I do have the wood in the rear mount. We checked the 4th main and it did not have any play in it but I have never checked the fan blade. Will try that next time we take the car out. A little history. When I bought the car and checked the serial numbers I found out that the engine was a "22 build and assumed the transmission was the same as it has the narrow brake band. I have found a 26 engine and transmission and will be installing it later this spring. The transmission is being rebuilt and the block and crank are getting some prep work done prior to assembly. Also getting a reconditioned balanced flywheel. I suspect that being new to the passion and having no experience working on a Model T was the cause of a quick assembly job that overlooked a lot stuff. The car is drivable right now up to about 32 mph and hopefully after the new engine and transmission it drive like it was new. I have driven a '25 touring that was as smooth as a modern car so that is what I am hoping happens to the coupe. Again thanks for the info.

Bill