The 'E' Type Forum

I want to convert my S3 Auto to manual and after reading a lot on this forum I think I will go down the 4 speed man OD route,
Does anyone know part numbers or things I should be looking out for to make sure I get the correct one for a V12 as I believe there are different jaguar boxes that people use in Mk2's etc

Thanks
Malky

You need a box which has the two threaded bosses on the rhs of the gearbox as the slave cylinder mounts to these.. Given that the xj12 went into production just before the etype v12, a box from at least 1970 or later will probably be when they started making them that way.

Other than that, it has to have the short top cover for the gear stick to come out in the right place.

The compact type A overdrive replaces the long tail so it'd have come out of a long wheelbase car.

kind regards
Marek

Hi Malki....first i have no experiance of 5 speeds and V12.....i do have a 4 syncro JBN box and compact overdrive in the for sale section.. viewtopic.php?f=7&t=11898 the top is from an XJ6 so dosent put the gear lever in tbe correct position.....im also not sure what bellhousing you will need......i knom a 4 syncro fits into the recess on the 4.2 bellhousing....but will the 4.2 bell fit the V12.....or does it need a V12 bell.....also what flywheel do you need.....there is a V12 4 syncro and bell for sale also in Ludlow....not mine https://www.ebay.co.uk/itm/ORIGINAL-Jag ... SwridaBGh8. Im not just pushing for a sale but if i can help with photos etc then contact me......i know that converting auto to manual can be awkward...all the best.. Steve

Hello Malky,

Unless you plan on always driving the car sedately, Its advisable to upgrade the overdrive to competition spec - springs, pump. UDC/ clutch etc.

Overdrive Spares can do this work for around £500.00 plus carriage plus VAT. The link to them follows:

http://www.odspares.com/phdi/p1.nsf/...ocument&part=2

or, they will supply the parts to DIY.

In answer to Steve's comment "but will the 4.2 bell fit the V12", no; accordingly, you will need a bell housing to suite.

As Marek suggests, the Type A (Laycock de Normanville) OD is the correct OD to use, as there is no requirement to do any modification to the body, or the remainder of the drive-line.

In my opinion, this is a good conversion for an S3, particularly if you want to maintain the correct look inside the cabin, with the original 4 speed pattern gear lever knob. We have done this conversion many times and use the right most rocker switch of the centre instrument panel (normally vacant unless your car is a 2+2 with a heated rear screen) for the OD switch.

If you buy a gearbox that wasn't originally equipped with an Over Drive unit, then you will need to get a Main Shaft that suits the OD. Look for a box that has a Serial Number suffixed with an N, indicating that it was equipped with a Laycock de Normanville OD. If you do get such a gearbox, but missing the OD, it should have a large nut on the Main Shaft, outboard of the rear bearing. If the serial number suffix is correct and its missing the OD unit, with no indication of it being able to take such a nut (no thread on the Main Shaft just after the rear bearing), then its been converted to not use an OD and you will be again looking for a correct Main Shaft.

Regards,

Bill

Bill, As you have done the conversion many times is there a difference in the transmission tunnel width?
Is is tighter after the pedal box is installed and is there room to rest your left foot or does it have to hover over the clutch pedal?

Regards
Malcolm

Malcolm Wrote:

Bill, As you have done the conversion many times is there a difference in the transmission tunnel width?
Is is tighter after the pedal box is installed and is there room to rest your left foot or does it have to hover over the clutch pedal?

Hello Malcolm,
The pedal box is the same unit as the Auto, but with an additional pedal hanging down. The transmission tunnel is exactly the same for a Manual and Auto car, the only difference being the top cover that doesn't alter the tunnel in any way. Except for the addition of the OD unit, the finished project will result in a car that is the same as a factory built manual vehicle, with the same degree of comfort/discomfort that may be perceived comes with a manual car. There is room to rest your foot and I don't find driving a manual S3 uncomfortable in the slightest.

Regards,

Bill

PM Sent

mgcjag wrote: ↑

Sat Feb 10, 2018 8:01 pm

Hi Malki....first i have no experiance of 5 speeds and V12.....i do have a 4 syncro JBN box and compact overdrive in the for sale section.. viewtopic.php?f=7&t=11898 the top is from an XJ6 so dosent put the gear lever in tbe correct position.....im also not sure what bellhousing you will need......i knom a 4 syncro fits into the recess on the 4.2 bellhousing....but will the 4.2 bell fit the V12.....or does it need a V12 bell.....also what flywheel do you need.....there is a V12 4 syncro and bell for sale also in Ludlow....not mine https://www.ebay.co.uk/itm/ORIGINAL-Jag ... SwridaBGh8. Im not just pushing for a sale but if i can help with photos etc then contact me......i know that converting auto to manual can be awkward...all the best.. Steve

Hi Steve, thanks for your reply, I think your box does not have the two bosses on the RH side for the clutch slave so it would not be any good to me, or has it?
Thanks
Malky

Hi Malky....my box dosnt have the 2 bosses......but on a 4.2 the slave bolts to the bellhousing....what im confused about is that as far as im aware compact overdrives were only fitted to 4 syncro boxes in 4.2.......you can obviously get 4 syncro with the bosses for the V12 like in the link i posted above but no ovetdrive....but what car would have a box with bosses and overdrive for V12......suggest you contact Bill from the posts above for suggestions.... Steve

I was told an XJ6 s1 or maybe 2 and a Mk10 but I don't know anything about this so thats why the forum is great

Hi Malky...im fairly sure s1/2 xj6 slave mount on the bell housing....S3 had 5 speed gearbox....mk 10 dont think had 4 syncro.....you need to find someone who has a V12 with overdrive...Bill said he,s done it..pm him.....please keep this thread going..... Steve

Hello Steve,
The attached picture below shows an authentic Overdrive Gearbox sourced from an XJ6, complete with the Slave Cylinder Mounting on the side of the Gearbox and on the Bell Housing.



MK10's were available with a 4 speed synchromesh box, but didn't have the mounting on the side of the gearbox for a slave cylinder. However, the Top Cover has the same gear lever position as an E-Type.

The following picture shows the Main Shaft with nut aft of rear bearing if a gearbox without the OD unit is found. This is the Main Shaft required for a Type A, Laycock de Normanville ODrive unit.



Regards,

Bill

Hi Bill.....so is that a KFN gearbox....and will all KFN have the 2 bosses.....thanks... Steve

Hello Steve,
Yes, this a KFN box and has the Slave Cylinder Mounting on the side of the box, blanked off with the two bolts shown. Its my understanding that all KF boxes have the Gearbox mount for the Slave Cylinder; at least all that I've handled have. The "N" in the Prefix simply refers to the Gearbox being originally equipped with a Laycock de Normanville OD.

There are "work arounds" to be able to use a box without the mounting for the Slave Cylinder on the side of the Gearbox, with a V12 engine.

Regards,

Bill

Hi Bill.....you cant leave us hanging....what are the workarounds......drilling and tapping tha case? All the best.. Steve

Hello Steve,
I have the benefit of a well equipped CNC machine shop, but the same operations can be done on a manual milling machine.

1. Spot Face dia 3/4" (19.05mm) at the location of where the mounting points should be. You can't go very deep with these due to the relatively thin wall thickness of the Gearbox. You won't get a full Spot Face for the boss.

2. Drill and Tap through the wall of the Gearbox to take 3/8" UNF threaded studs.

3. Drill and Tap two x 19.0mm bosses 3/8 UNF

4. Using Loctite, Screw Threaded studs through bosses to have the wall thickness of the Gearbox, of thread protrude.

5. Using Loctite, Screw wall thickness length of protruding thread into the drilled/tapped holes in Gearbox wall and tighten.

6. The length of the Threaded Stud now protruding from the boss should be sufficient to pass through the mounting holes in the slave cylinder housing and take a washer and nut.

I make the boss as an integral part of the threaded stud, so that its a solid part. If you don't have access to a lathe, making the stud with separate boss component as stated above works.

The other "work around" is to install an after market, hydraulically actuated thrust bearing unit. There are many and varied examples of these available. This is arguably the better solution, as it gets rid of the original solid thrust pad.

I've only done a few conversions using gearboxes missing the Gearbox Mount for the slave cylinder, as we are usually able to find KF boxes. The hardest part in Australia is finding Top Covers to put the gear lever in the correct position. You don't seem to find junked E Type gearboxes ten deep at the dump.

Regards,

Bill

Bill....as ever a great explenation.....I like the sound of the hydraulically opetaterared thrust dearing...theres now enough information in his thread to identify or modify a gearbox/overdrive to suit a V12.......thanks..... Steve

If I HAD to use an early box on a V12, I’d fit an hydraulic throw-out bearing. Not any simpler but more places will probably know how to do it.

Nit-pick alert:

For the sake of newbies like the OP, we have to stop calling the correct overdrive a Type A. A Type A is the big version used on Mk2s etc. If the ID plate says Type A do not buy it.

The correct version is ‘Compact Type A’ and almost always uses that name on the ID plate. More than one buyer has fallen into this trap, which reminds me of the MkX triple SU manifold scan.

Soapbox put away for now...

Seems to me that getting hold of a mainshaft from a Jaguar KFN gearbox will be the biggest problem - do we know if these gearboxes, or shafts where unique to Jaguar, BL were doing a fair bit of economising at the time?

Also, this post: http://www.xketype.com/e107_plugins/con ... content.18
talks about there being a bearing oil pump in the tail housing that would be replaced by the o/d unit. Is this correct?

Colin Wrote:

Also, this post: http://www.xketype.com/e107_plugins/con ... content.18
talks about there being a bearing oil pump in the tail housing that would be replaced by the o/d unit. Is this correct?

Hello Colin,
Yes, that’s correct. The oil pump for a 4 speed all synchromesh Jag G/Box, without an OD, is driven by the Inner Race of the rear bearing (by friction), where the large nut is shown on the Main Shaft in the following picture.



This picture is of a KFN (XJ6) G/Box minus the Laycock de Normanville Overdrive it was originally equipped with. And yes, this Main Shaft is rather hard to come by, particularly here in Australia. Accordingly, the best option is to source a complete G/Box – Overdrive package.

As Pete points out, it is the Compact Type A with the corresponding ID Tag shown in the following picture, that's required.



Regards,

Bill