Gearbox internal parts compatibility

[iain1967s]

Time to learn something new...

After a year of looking I finally managed to pick up a 22G333 Q gearbox case for my ongoing Mk1 1275 S restoration.

It’s just a bare casing, and I expect it will take me a good while longer to accumulate all the parts to build it up - I’m in no rush - but what I don’t know, is which gearbox parts are compatible with which cases.

Assuming standard helical gears for general road use - not close ratio etc - is there anything internally which is specific to the 333 box, or are all A-series ’3 synchro B’ internals generally compatible?

For example, can I can use parts such as linkages, selectors, diff cage and gears from a donor 22G68 magic wand box, refurb them with a rebuild kit, and assemble them into the 22G333 casing?

Build deviations will include a 3.44 or taller FD and changing from cruciform to hardy spicer outputs. Is that just a straight swap of crown wheel and pinion, diff output shafts and side covers?

[Also, I’ve read that the MG Midget 3 synchro box used the same internal gears, but obviously not the diff, and that might be an easier source of spares here in the USA]

Thanks for any pointers.

[ricardo]

You can use all the internals from the 22G68 box to build up the 333. That should have a gearset based on the 22G231 laygear (I say should because it is magic wand, opposed to a remote type from a 998 cooper which normally are based on the 22G232 gearset) which is the standard road gearset.

The 333 original gearset is the 22G232/22G1100 (same, renumbered) and that is known as the close ratio gearset. The reverse, both synchro hubs and second gear are shared between the 231 and 232/1100 gearsets (both are B type). The laygear from minispares is good, so the difficult gears are 3rd and the first motion shaft.

I can probably help with some NOS gears if you need them.

The selector rods and forks can be those from the 22G68 box as well as the mainshaft, locking gates, bearings (buy new but they're the same). The idler gear bearing will be different though.

[iain1967s]

Thanks Ricardo, very helpful. I’m going to see what guessworks can do for me, if not I will buy a donor 22G68 off eBay and start doing it myself...

As usual with being on the wrong side of the pond, it’s the limited parts supply in USA and the high costs of international shipping that limit my options.

[Andrew1967]

The Midget laygear, 22G232/1100, is the same but I don't think anything else is.

[spoon.450]

That's great information Andrew. Out of interest, what's different about the idler gear bearing in a 333 box compared to any other early ( 1 " diameter bearing ) box ?

[Andrew1967]

I wasn't aware there was any difference. That said, I've only ever had (now got) one 333 box so will have to have a look.

On the look out for a 'Y' 333 casing if anyone has anything

[spoon.450]

Sorry Andrew..... I mis read My question was intended for ricardo after reading his informative post. ricardo, can you inform of any differences between the idler gear bearings please ? Thanks, Dave

[Andrew1967]

No worries Dave

[ricardo]

Dave,

the early 3 synchro boxes, like 22G68, use the smaller 88G302 bearing. This is the same bearing used on the front top suspension arms and the early flywheel housings (22A108/22A524 if memory serves me right).

The 333 box on the other hand uses the bigger bearing, 13H7848, which is the same as those used on early 4 synchro boxes (22G1128 / 22G486).

I believe the S flywheel housing (22A208) uses the larger bearing as well, so both sides of the idler gear are supported by the same type of bearing (although I couldn't confirm that so far).

Having said this, I've heard of 333 boxes with the smaller bearing. Maybe very early ones were like that, but I never seen one. I have a Y type and a Q type and both have the larger item.

Now we should look at some 190 boxes and see what they have

[spoon.450]

I have a 190 here that has the 1 inch dia bearing, and have had two 333's also with the small bearing...….

[ricardo]

Makes sense the 190 box having the smaller bearing.

Regarding the idler bearing, there are 2 types of 333 boxes then. This is my Y case, the bearing hole was not opened up. As you can see it has the larger bearing.

Now that I mention it, I also have a 22A1288 box (3 synchro) which has the larger bearing as well. But that is a later casting, from a 998 Cooper.

[iain1967s]

Well, my 22G333 casing arrived and is as described - completely stripped but no damage or cracks, except for a few slightly chipped fins, and a stress line near the engine mount on the clutch cover (which I wasn’t going to use anyway). Even the drain plug thread is good!

However, my quest to find a donor parts ‘B’ 3-synchro gearbox isn’t going so well.

I put out a call to our local mini club, and I’ve ended up with three gearboxes being offered. They are certainly 3-synchro, but all 3 are the earlier cone rather than baulk ring style.

Case # 22A104 Laygear # G40
Case # 22A145 Laygear # G40
Case # 22A363 Laygear # G40

I don’t think they are going to be much use as donors for my Cooper S gearbox. Guess I’ll have to keep looking.

[ricardo]

Iain,

Your case looks good. The boxes you mention are very early boxes with A type gears.

If it was me, I would stick to B type gears, they're easier to find in good condition and MS / Minimania should have all the bits you need for the rebuild.

You can lookup for a B type gearset in the following boxes: 22G333 (of course), 22G68, 22A1288 and 22A1522.

Lookup for the reference stamped in the laygear: 22G231 (standard) or 22G232/22G1100 (close...r ratio).

Only the laygear, third gear and first motion shaft are specific for each gearset, everything else is interchangeable, so that's makes thing easier even if you start with a standard set and then later want to upgrade to the S set.

I believe the 1100/1300 range (Austin/Morris/MG) shared some of these boxes, so extend your search for those as well.

Hope this is of some help.

[iain1967s]

Thanks Ricardo. Sure enough I found a helical "S" laygear (22G232 / 22G1100) relatively easily, from the MG Midget parts bin... but the "S" 20 tooth first motion (22G322 / 22A982) and the 24 tooth third gear (22A557 / 22A983) are elusive, as I thought they might be.

I haven't given up yet, but I am considering using either the 22G231 non-S ratios, or the widely available AJJ3371 "ST" straight cut gear set (but keeping the helical drop gears)

Per Mark's table and ST info, there are five ‘B’ gear options:
22G231 3-synchro helical standard ratios 3.63, 2.17, 1.54, 1.0 (non-S standard)
22G232 3-synchro helical “S” ratios 3.2, 1.92, 1.36, 1.0 (22G333 standard)
22G210 3-synchro helical “S” close ratios 2.57, 1.78, 1.24, 1.0 (22G333 close ratio)
22G335 3-synchro spur “ST” std ratios 3.08, 1.88, 1.31, 1.0 (22G333 straight cut)
22G306 3-synchro spur “ST” close ratios 2.57, 1.72, 1.25, 1.0 (22G333 straight cut close ratio)

My 1293 S engine currently sits on a 22G846 4-syncro gearbox with a 3.65 diff. I don't know what laygear is in the current box, but first gear is so short with that FD it's practically useless - I can easily start off in second without slipping the clutch, and it's revving its nuts off by 75 MPH in top gear...

I have no experience driving with either of the "S" or the "ST" close-ratio gearbox, and my concern is that 1st gear on the "ST ratio" is very long, and might be a step too far - I'm not building a race car, I just want something close to what my car would have driven like when it was built in 1967.

Any thoughts?

[iain1967s]

I should add that I'll definitely be using a 3.44 FD on the 22G333 - I have an “S” diff with Hardy Spicer outputs that I’m currently rebuilding to install into that casing.

Comparing to the 4-synchro standard ratios of 3.52, 2.22, 2.03, 1.0 (which I am assumimg is what I have currently) my gut feel is that the 1st gear of 2.57 on 3.44 FD is roughly where 2nd gear 2.22 on 3.65 FD in with my current box, so it might be OK?

[ricardo]

In my opinion the 3.65 is too short for a road 1275.

I have a 3.44 in mine with a 22G232 gearset and I think it is well balanced for the roads I use. The car is quick to respond, pulls very nicely from start and begins being a bit loud around 65mph/100kph (I don't use the highway much, so that's ok). Depending on your driving style and roads you have there in the US you may even consider a 3.2 or 3.1 diff.

As for the gearset, I can't help much with an opinion, my experience is mainly with the 22G232 and 22G1040 (4 synchro) gearsets. They're both good enough for me.

[iain1967s]

Snowing here today... a good excuse to stay indoors and strip down a donor 3-synchro 22A363 A-type magic wand box, then start building up the new parts into my 333 B-type casing

Thanks to several forum members, I now have a nearly-complete NOS set of the S ratio helical gears. Just waiting on MiniSpares for a new laygear, needle bearings and 1/2nd synchro hub.

Ricardo was right - there isn’t too much that is reusable, as well as the gears being completely different the A-type box also has a smaller diameter mainshaft. But it is a useful source for misc hardware items such as the selector mechanisms, oil pickup, speedo drive and input gear.

[scott6058]

I was able to source a late 3 sync box with perfect gears 22A1522 with H/S and a 3:44 diff.
Some will say a 190 box never had H/S but it will be more reliable in my opinion.

[iain1967s]

Bugger...

Four months after I started this build, I thought I finally had all the parts ready to put the gearbox together today.

But when I assembled the mainshaft, the 24 tooth third gear I bought via Facebook (from someone who is also a forum member) turns out to be A-type, so obviously it doesn’t mesh with the B-type laygear.

I’m sure it was a genuine mistake, I certainly didn’t notice the different tooth angle when the gear was on its own, but obvious to spot once assembled - see photo.

Unfortunately that brings my build to a halt - I’m back to looking for a B-type 24 tooth third gear (22A557 / 22A983), the last part I need to complete my 333 gearbox.

[abri]

That's a bummer...I hope you're successful in your search soon.

Are any of the cone synchro gears you have usable? I have a 104 gearbox that needs some gears.