Moss Gearbox - Plungers into Striking Rods
#1
07-30-2017, 05:54 PM
Moss Gearbox - Plungers into Striking Rods
Hello Everybody,
As I'm rebuilding the engine in my '56 XK140MC FHC, I couldn't resist looking into the Moss Gearbox while I had it out of the car. The Overdrive wasn't working so I had it rebuilt (not by me, I try to be realistic regarding my limitations). It felt like a natural move for me to peek into the gearbox.
All looked remarkably clean and in good shape. I did come across an NOS 1st/2nd Gear Fork, so I replaced that part, even though there really wasn't much wear on the old one. I also have replaced all gaskets, seals, bearings, and springs, since those parts aren't very expensive. Plus, I had the gearbox apart and couldn't resist the temptation. I also set the end float on the countershaft since it was quite a bit out of specification.
I got the transmission back together, and all seems right. I then moved to the top cover and replaced all bushings, washers and seals. It's back together and the gearbox shifts nice and crisp on my workbench.
The last thing for me to do before closing up the gearbox is to set the tension on the plungers into the striking rods. This is accomplished by tightening the 3 grub screws (1 for each striking rod) at the rear of the top cover. I've not found much guidance on how much to tighten these grub screws before securing them with safety wire. Obviously, if they're too loose the shifting feels a bit mushy and the gearbox may pop out of gear. On the other hand, if they're too tight, the shifting will be stiff and there may be premature wear on the tips of the plungers and the striking rods.
So, my question is, do any of you have any advice as to how much to tighten the grub screws? I realize that it's probably a matter of tightening them "just enough", but I thought I'd ask anyway.
Any advice will be most appreciated. Thank you.
Borron
As I'm rebuilding the engine in my '56 XK140MC FHC, I couldn't resist looking into the Moss Gearbox while I had it out of the car. The Overdrive wasn't working so I had it rebuilt (not by me, I try to be realistic regarding my limitations). It felt like a natural move for me to peek into the gearbox.
All looked remarkably clean and in good shape. I did come across an NOS 1st/2nd Gear Fork, so I replaced that part, even though there really wasn't much wear on the old one. I also have replaced all gaskets, seals, bearings, and springs, since those parts aren't very expensive. Plus, I had the gearbox apart and couldn't resist the temptation. I also set the end float on the countershaft since it was quite a bit out of specification.
I got the transmission back together, and all seems right. I then moved to the top cover and replaced all bushings, washers and seals. It's back together and the gearbox shifts nice and crisp on my workbench.
The last thing for me to do before closing up the gearbox is to set the tension on the plungers into the striking rods. This is accomplished by tightening the 3 grub screws (1 for each striking rod) at the rear of the top cover. I've not found much guidance on how much to tighten these grub screws before securing them with safety wire. Obviously, if they're too loose the shifting feels a bit mushy and the gearbox may pop out of gear. On the other hand, if they're too tight, the shifting will be stiff and there may be premature wear on the tips of the plungers and the striking rods.
So, my question is, do any of you have any advice as to how much to tighten the grub screws? I realize that it's probably a matter of tightening them "just enough", but I thought I'd ask anyway.
Any advice will be most appreciated. Thank you.
Borron