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I have a Moss 4 speed with no 1 gear synchronizer and a Laycock overdrive. Is it possible to replace the overdrive with a standard tail housing? Does the overdrive unit require a specific length output shaft that's different than a non overdrive?
As no one else has chimed in, I'll at least bump the question up the list.
I don't know the answer to your question off the top of my head, but I don't think it's going to be as easy as it sounds. Apart from the mechanics, there's the problem of finding the parts. There can't be many non-o/d Moss tail housings around without a gearbox attached. You could just leave the o/d in place. So long as it's not seized solid and the housing isn't fractured, it's not doing any harm. The Laycock o/d is a neat device and nice to have. It's very pleasant for cruising. It's worth trying to find out what's wrong with it and repairing it. Often the fault is in the electrical connections or the adjustment of the solenoid. The one of the service manuals below may help. The Ferrari version is more impressive for showing to your friends ... though the content is much the same .
BTW ~ Dave Twigger at Overdrive Spares in Rugby knows more about Laycock DN Overdrives than most on the planet. He is a most helpful gent & more than happy to help even if he sells you nothing.
Glyn, The Mk2 spares manual lists different prop shafts for O/D, standard, and auto transmissions. Within those, the shaft changes over the years, but I think the length remains constant for each transmission option. Diameters and various details change. All this may be a academic as I think Jay wants this for his vintage racer and the prop shaft will be a one off anyway. I'll second the suggestion of contacting Dave Twigger in Rugby.
When I removed the drain plug, there were dried oil chunks and lots of large metal chips. There's a 3/16" hole in the case near the drain plug, like a small cavern in the wall of the case. It looks like a casting issue, someone has JB Welded the inside of the case.
It may have run low on oil at some point, and damaged some of the internals. It's unfortunate as the Moss had all new internals, including the bronze shift forks.
I have a WC T5 from a Camaro, looking for a longer input shaft so I can use an adapter plate on the Jaguar bell housing.
I have a WC T5 from a Camaro, looking for a longer input shaft so I can use an adapter plate on the Jaguar bell housing.
I used a Ford Mustang version of the T5, it works with the Jaguar bellhousing. You'll need a 1/2" thick adapter plate between the bell housing and the transmission, and then use the Jaguar bell housing, clutch cover and release bearing. I needed to get a clutch disk made with the Ford spline and Jaguar clutch cover diameter. The bellhousing needed to be opened up slightly to fit over the transmission bearing housing, but it wasn't much material that needed to be removed. You'll also need to machine up a crankshaft pilot bearing, as the Ford input shaft is smaller than the Jaguar shaft diameter.
I took the overdrive apart today and what I thought was a JB Weld patch, was just more of the crusty dried out oil. So the hole does not go all the way through the case wall. I reinstalled the overdrive and just as the fasteners were tight the whole transmission would bind up. It turns out there's a case gasket missing on the overdrive, there's no end play at all. Backing off on the bolts 3/4 of turn is enough to free up the binding. The bearings look new, maybe it will be useable without the overdrive engaged. The overdrive is so much fun to install, I can't wait to take it apart again to install the gasket.
Now I know why the transmission was bound up when I got it.
The top cover is missing a couple of bolts. They appear to be BSW, does anyone know what thread pitch and diameter they are? I assume BSW also has different grades.
I just checked Ebay and they have listings of BSW hardware. They are listed as 1/4-20, 5/16-18, etc. The bolts in the transmission are not SAE, and the bolt head is not SAE or Metric wrench sizes.
I just checked Ebay and they have listings of BSW hardware. They are listed as 1/4-20, 5/16-18, etc. The bolts in the transmission are not SAE, and the bolt head is not SAE or Metric wrench sizes.
BSW, British Standard Whitworth...
I never referred to that thread type like that; I use BSF, or British Standard Fine, that would make a 1/4 inch thread at 26 threads per inch (TPI).
5/16 would be 22 TPI, 3/8 would be 20.
The pitch is different, but it's the odd thread count that will get you into trouble when it comes to its fine thread count.
My 51 Bentley is entirely made up of fine thread, and there are no BSC (British Standard Course) threads on the car.
I'm going to assume that if the bolts on your OD unit is BSF or Whitworth, then they will be a fine thread version of this thread scheme.
You will need some new tools to work on it, if it is indeed BSF
Britool makes sockets and wrenches, and I've had mine for over 20 years and they've stood up, but after searching, they don't seem to be around anymore.
If you are able to remove another bolt for the cover and positively I.D. it as BSF, then chances are I may have a couple of bolts I can give you.
This thread gauge will ID the the BSF threads, or you can simply use a rule and count them _ not the most accurate way, but there will be enough of a difference to tell.
Whitworth and BSF are essentially the same, but one uses the inside of the bolt as a way of measuring known as the "Minor Diameter", and the other uses the "Majour Diameter".
So there is 1/4 BSF and 3/16 Whitworth marked on one wrench where the 3/16 referes to the minor diameter of the thread on a quarter inch BSF bolt.
You may buy sockets and wrenches individually, and you won't need that many tools, there are not that many sizes.
1/4, 5/16 and 3/8 BSF are the most common.
BSW, British Standard Whitworth...
I never referred to that thread type like that; I use BSF, or British Standard Fine, that would make a 1/4 inch thread at 26 threads per inch (TPI).
5/16 would be 22 TPI, 3/8 would be 20.
The pitch is different, but it's the odd thread count that will get you into trouble when it comes to its fine thread count.
My 51 Bentley is entirely made up of fine thread, and there are no BSC (British Standard Course) threads on the car.
I'm going to assume that if the bolts on your OD unit is BSF or Whitworth, then they will be a fine thread version of this thread scheme.
You will need some new tools to work on it, if it is indeed BSF
Britool makes sockets and wrenches, and I've had mine for over 20 years and they've stood up, but after searching, they don't seem to be around anymore.
If you are able to remove another bolt for the cover and positively I.D. it as BSF, then chances are I may have a couple of bolts I can give you.
This thread gauge will ID the the BSF threads, or you can simply use a rule and count them _ not the most accurate way, but there will be enough of a difference to tell.
Whitworth and BSF are essentially the same, but one uses the inside of the bolt as a way of measuring known as the "Minor Diameter", and the other uses the "Majour Diameter".
So there is 1/4 BSF and 3/16 Whitworth marked on one wrench where the 3/16 referes to the minor diameter of the thread on a quarter inch BSF bolt.
You may buy sockets and wrenches individually, and you won't need that many tools, there are not that many sizes.
1/4, 5/16 and 3/8 BSF are the most common.
Hey,
Thanks for the information. In the 1970's, I owned a 1963 MGB, it must have been SAE as I don't remember needing any special tools.
This is my first encounter with the fasteners that were used on early British cars.
From the MK7 onwards Jaguar went SAE to meet the needs of the North American market which was their main export customer. So the MK1, Mk2, S type and 420 are SAE.
HOWEVER, sub parts providers like Lucas, Smiths and Moss etc. continued with Whitworth, BSF and BA and strange brass threads on things like Lucas driving light mounts on the MK1.
The bolts on the Moss box top plate are BSF.
Most of the nuts and bolts used are (UNC & UNF), a standard developed after WW2 so that English and American engineers were working to the same sizes. But there are some exceptions and if you start working on the carburettors, you will quickly find that your trusty AF socket set isn't much help. This is because when they made the H4 carburettor, SU were still using bolt head sizes common to British Standard Fine/Whitworth threads (BSF/BSW).
Rather than risk damaging the various carburettor fixings, it is best to get the right spanners up front. The three sizes you will need are:
3/16"BSF / 1/4" BSW
Float chamber lid retaining hollow bolt
1/4" BSF / 5/16"BSW
Jet adjusting nut
3/8"BSF / 7/16" BSW
Float Chamber Retaining Bolt
Jet Locking Nut
Fuel Line Banjo Bolt
Dashpot Brass Cap (later black plastic)
You will note that in each case the BSW size is 1/16" larger for the same bolt head size. You probably know this already.
Last edited by Glyn M Ruck; Mar 15, 2024 at 11:48 AM.
Moss 4 Speed with bad overdrive
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