Classic cars forum & vehicle restoration.

[Mark_S]

Hello,

I would like to convert my Series 2 from 3 speed to 4 speed. In my hometown there are several small hills and the jump from 2nd to 3rd gear is quite heavy.

I got a 4 speed gearbox from Series E. The 4 speed gearbox though is significantly longer

Now I have already 2 issues.

1. The main drive shaft is too long
Questions:
- Is the Series E drive shaft shorter?
- How long is it?
- Does anyone have a spare one?

2. The rear mountings are different. The 3 speed gearbox has a mounting plate while the 4 speed has not. The distance between the bolts is also different.
Questions:
- Are the frame attachments the same?
- Where could I get the rear mountings of a series E?

Should I expect more issues once I have taken out the 3 speed gearbox?


Looking forward to your suggestions.

Best regards

Mark

[ukdave2002]

Hi Mark

What a coincidence, I've just come in for a cup of tea, in the middle of rebuilding a Series E gearbox !

The input shaft (flywheel end that connect to the main shaft) is longer and wider on the series E, this is because on the pre series it locates in a bearing in the flywheel. On the series E it locates in a bush in the crank; you have 3 options:

1) take the bearing out of the flywheel, and insert an 3/4 x 5/8 oilite bush into the end of the crank, the series E box will now bolt straight on.

2) turn the end of the input shaft down to the same dimensions as the pre series input shaft.

3) fit the pre series input shaft to the series E box, it's a straight swap.


Re the mounting, Austin/Morris 1100/1300 rear subframe mounts have proved successful, you really just need to fabricate something that's man enough for the job, I've seen others using a couple of exhaust mounts.

It's a popular conversion that make a positive difference to the car, shout if you need more help.

Dave

[Mark_S]

Hello Dave,

thanks a lot for your reply.

Had to learn something today.javascript:emoticon('')

Don't believe the obvious. I turned down the shaft to the preseries dimensions and was quite proud about the result. When I checked how it fits to the crankshaft guide bearing I had to learn that the new engine it got has the series E bearing in the crankshaft. I did not see it as the clutch was still mounted and a metal shield was hiding the bearing. This means though that the current gearbox did not run with a pilot bearing. javascript:emoticon('')

Now I see 3 options:

1. turn a bearing in brass which will fit behind the metal shield with a 12mm bore. (could be done tomorrow)

2. get a new Series E shaft (bit more difficult)

3. fit a ball bearing behind the metal shield (need to measure more accurate tomorrow. There are bearings available in 12/32 mm, which is quite close.



Would you mind measuring the drive shaft length as I will have again 2 options

1. shorten the current drive shaft

2. find a Series E type

Your thoughts are welcome.

Best regards

Mark

[goneps]

[goneps]

Mark,

I did this conversion a couple of years ago (my UB engine already had a counterbalanced crankshaft) and have extensive pictures and notes from the job, which might help you. Although the mechanical conversion is fairly straightforward there are numerous issues concerning getting the car to fit around the much larger E 'box, which you'll have to deal with. There's also the not-so-small matter that the speedometer drive gearing is very different, and it's not just a simple matter of swapping components.

Let me know if you'd like the pictures and other info., but before I can post them I'll have to follow the instructions re. Photobucket and all that nonsense, so it won't happen straight away.

Richard

[Mark_S]

[ukdave2002]

Hi Mark

I think your best option would be to fit a bearing, and fabricate a cover plate; it's only a simple bit of pressed steel.

After some consultation with Richard, we have identified the bearing you need is a 6201ZZ , originally Morris fitted a self aligning bearing (1201) you can purchase either of them from the supplier link below.

http://simplybearings.co.uk/shop/advanced_search_result.php?search_in_description=0&sort=2a&search_3fields=1&keywords1=12&keywords2=32&keywords3=10&keywords=12x32x10%2032x10x12%2010x32x12%2032x12x10%2010x12x32%2032x12x10&&page=1

Cheers Dave

[Mark_S]

Hello,

bearing fitted. Fits perfect. Metal shield was there but no bearing. At the same time I secured the bolts with wire-locks which was also not done. Previous owner talked about an expert who replaced the engine. Need to think about definition of expert.

Next job will now be to rebuild the gearbox.
This needs to wait 1 or 2 weeks as I am waiting for a washing station.

I also talked to a local classic car workshop. They can shorten the prop shaft and balance it also.

In the meantime I will service the break master cylinder.

I will keep you posted. Thanks for your support.

Mark

[goneps]

Mark,

Since you're about to rip apart your 4-speed gearbox you have an excellent opportunity to overcome the problem of the incorrect speedometer gearing. For the record, the Series E gearbox speedometer drive translates the output shaft motion to 1600 revolutions of the cable per mile, whereas on the 3-speed it's only 1000, so a significant difference.

Theoretically you could have an instrument technician recalibrate your S2 speedo to suit, or fit one of those expensive little cable gearboxes from Speedograph Richfield, but there are better alternatives.

Easily the best, in my opinion, is to transfer the worm drive components from a 3-speed 'box (I'd salvaged the parts from an otherwise irreparable unit). On the 3-speed the spiral worm drive gear is machined on the output (prop shaft) flange, whereas in the 4-speed it's a separate item mounted on the extension shaft. The 3-speed item was machined off the flange to the same dimensions as the 4-speed, and transferred together with its matching worm to the 4-speed. DO NOT MIX UP THE WORMS AND DRIVE GEARS—they are incompatible and will rapidly destroy themselves if not kept as a matching pair.

Another reasonably neat option is to use the 'guts' of a Series E speedometer in the car. Although the face of the E instrument is much larger, the body containing the mechanism is the same as that of the earlier cars. However, this will still require the instrument to be calibrated since the needle has to be removed to change the face. Changing the worm drive in the gearbox is, in my view, by far the most elegant solution—presuming you have a 3-speed unit from which to cannibalise the parts.

Richard

[goneps]

This picture shows initial 4-speed installation completed.



What follows are some implications of the conversion that are not usually considered, but may influence the decision to proceed.

The drawbacks.

1. In this thread we’ve already dealt with the longer spigot shaft and speedometer gearing, so no point in repeating them.
2. The 3-speed clutch thrust bearing fork, together with its cross shaft, pedal, and spring, must be transferred to the 4-speed unit.
3. The gear lever has a different shape. I modified mine to bring the knob to the same position as with the 3-speed, bearing in mind that the turret of the gearbox cover sits 1/2” further back. Gear levers are not interchangeable, and I would advise against removing the lever from its cover because it’s extremely difficult to reinstall.
4. The 4-speed unit is 6 1/4” longer than the one it replaces, so the prop shaft has to be shortened by this amount and a new mounting arrangement devised (details of the latter to follow).
5. The gearbox moulded rubber cover will not fit over the much wider 4-speed unit, and in any case as mentioned above the gear lever is positioned further back. Some modification of the toeboard and nearside floorboard is also necessary.
6. The transmission tunnel needs extensive modification to its leading edge and both supporting legs. Considering that the latter support the floorboards it’s advisable to weld in a stiffening gusset on each side, to restore the legs’ strength.

The benefits.

1. The gear ratios endow the car with a very different feel. First and second speeds are lower than their 3-speed equivalents, and third is only a little higher than the 3-speed’s second. See table below.
2. That said, the extra 5mph at maximum revs in third (compared with 3-speed second) makes a disproportionate difference to hill-climbing ability, and the closer spacing means that on all but the steepest hills one is not constrained to a slow grind in second, as with the 3-speed.
3. For most purposes third may be used where second served previously, but obviously has much ‘longer legs’.
4. On the level, second is quite adequate for moving off from rest, particularly if the car is only moderately loaded.
5. Overall the car feels much more relaxed and it’s hardly necessary to rev the engine at all, except for upward gear-changes on inclines.

[ukdave2002]

Hi Mark

If you are rebuilding the gearbox the following may help you source the bearings, the bearing numbers are universal, the bush numbers are Oilite.

Series E Gearbox bearings

Input shaft drive gear, Morris part number ;X15625 :
LJ1NR Imperial Open Snap Ring Type Open Deep Groove Ball Bearing 1x2-1/4x5/8 inch Also known asRLS8NR


Main shaft front, Morris Part number; X15625:
LJ1NR Imperial Open Snap Ring Type Open Deep Groove Ball Bearing 1x2-1/4x5/8 inch Also known asRLS8NR


Main shaft rear, Morris part number; QA11033:
6205, Metal Shielded Deep Groove Ball Bearing 25x52x15mm consider replacing with 62052RS for better oil sealing.

Layshaft bush (x2) Morris part number X15523:
AI1012-20 Oil Filled Bronze Plain Bush 5/8x3/4x1-1/4 inch. The layshafts are normally worn, a new one can be made up quite easily from 5/8" ground steel shafting.

Clutch pivot shaft (x2) Morris part number X19325:
AI1012-16 Oil Filled Bronze Plain Bush 5/8x3/4x1 inch

Input shaft spigot bush, Morris part number X15075:
AI0810-16 Oil Filled Bronze Plain Bush 1/2x5/8x1 inch

Reverse gear bush, Morris part number X17342. Originally a single bush, now difficult to source so substitute 2 shorter bushes:
AI1012-16 Oil Filled Bronze Plain Bush 5/8x3/4x1 inch. The are often not worn so won't need changing in many cases.

Dave

[Mark_S]

Hello Dave, Richard,

thank you so much.

I have now turned down the speedometer worm gear drive and it fits very well.

I also changed the broken spring in the gear lever and bent the lever at the same angle.

At the moment I am struggeling a bit with the rear mounts, but I think I found a nice way finally.

For the rear bearing I bought an open one, but I think you are right to go for a 2RS / 2Z. I will get one later this week.

Prop shaft is at the dealer for shortening.

Now with the information about the bushings I may need to make another round and buy some pieces.

Best regards

Mark

[goneps]

Mark,

Herewith details of mounting arrangement. This is the most popular method among Morris Register members. It comprises a BMC 1100 rear subframe mounting that, with a little modification, results in a strong and tidy installation as shown. The mounting bolts directly to the top of the cross-member, so only two holes need be drilled therein.





When modifying the mounting make sure not to leave any sharp corners that might cause stress cracks.

Mount as purchased.


After modification.


As the pictures show, only the two centre gearbox mounting points are used, but these are more than adequate. Hardened flat washers need to be used for the nut and bolt over the slots; ordinary washers will simply 'dish' into the slots.

The outer left side stud should be removed and replaced with a bolt M8 x 1.0 x 30mm., otherwise it will get in the way later (the hole needs to be plugged to prevent oil leaking out).

I used the right outer mounting hole on the gearbox to attach the chassis earthing cable. The external thread of the studs is 3/8" BSF.

Richard

[goneps]

These are pictures of necessary modifications to the transmission tunnel (front metal section).

Position of tunnel without modification


Cut and bend front section.



Left leg modified.


Right leg modified


Reinforcing gussets welded to legs.



View from top after mods completed


The final stage concerns the gearbox cover. As mentioned earlier, the original rubber cover will no longer fit. The cover on my Tourer had been replaced by a fibreglass reproduction cover when restored in the 'seventies, so I constructed a mould from scratch and made a slightly larger one. It was no easy job, and took five months to complete. Unfortunately it proved impossible to remove the new cover without destroying the mould.

The object of going to so much trouble was to retain the car's original appearance as far as possible. There's no evidence that it's not the original 3-speed gearbox unless you crawl underneath.

Good luck, and let us know if you need any further info.

Richard

[Rosco663]