Beck TD, Part 57: Overdrive Success!

After my recent post about my attempt to understand how my M41 overdrive does its work, I was ready to reassemble. I used a lot of new parts, including all three bearings in the overdrive unit, and all the parts still available via Moss Motors - mainly o-rings, a spring or two, various seals and washers. I won't bore you with pictures of the assembly, because it is extremely well-documented in this pair of videos by John 'The Box' Roseby on The Sunbeam Alpine Channel on YouTube:

Disassembly: https://youtu.be/Ht6eb7w4gto

Assembly: https://youtu.be/WvAjwhIaSzw

Once it was done, I installed the overdrive unit on the transmission, and set it on my crude but effective test stand:

Beck TD, Part 56: Understanding my M41 Overdrive (Laycock D-Type)

At the end of Part 2 of this overdrive saga, when I had just gotten the transmission working (minus the overdrive unit), I promised I would try to actually understand how the overdrive works. I've made some good strides toward that goal, so I'm going to try to tell you what I've learned. Nothing like trying to teach something to tell you what you don't understand...

Here's the problem: most of the multitudes of books and web pages I reviewed assume you know certain things. For instance, what all the parts inside of the overdrive are called, and maybe how they go together. So, if it refers to the "annulus" you have to have some sense of what that is. In addition, there are cryptic, color-coded cut-away diagrams that are difficult to read if you've never held the parts in your hands. Not ideal for beginners.

I'm going to try it a different way, leading you through discovering certain points based on pictures of the individual components. Let's start with this one:

Beck TD, Part 55: Tom Bryant's SU Carb Tuning Procedure

When I rebuilt the SU HS6 carbs in Beck, I followed the online procedure published by Tom Bryant, who has rebuilt hundreds of sets. It worked great, although I couldn't know it right away because the engine in Beck was in such poor shape. After installing a used engine I procured from Joe Lazenby, I installed my rebuilt carbs and proved that I had done it right.

When I first set them up, I purposely left them "fat" at Cor Engelen's advice - he noted that it would do no harm to be a bit rich, but you could burn a valve if they were too lean. It ran fine, but blackened the plugs after a few hundred miles. I decided today, when PA weather was gloriously warm and sunny, was a great day to tune them better.