Going from reverse to first is quicker with a non-syncro first gear. The syncro on the later box slows the shift down.
It is hard on the box though! Maybe that is why my S started jumping out of first gear?

All my Minis have had the three synchro Mki S box, even the van. Many old school Mini racers preferred this box claiming it was lighter and fractionally quicker to shift than the 4 speed synchro.

My Cooper S has got the ST three synchro cr/sc gearset but still in a 3 synchro box even though it's a MK2 S ( I sold the original 4 speed box to Tony Cullen back in 75). Double de-clutching to get into first if necessary, but to be honest I've never missed the lack of synchro on first in a Mini. I've got it on the Rover SD1 but seldom use it.

The main problem was people would try to put these boxes into first without de-clutching and still on the move leading to chipped teeth on first gear. I don't think the 3 synchro first gear assemblies are available new anymore, or at least they weren't last time I checked. Is anyone re-manufacturing them?

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Slide
1965 Mini Van (1360)
1970 Mk2 Cooper S (1310)
1978 Rover SD1 V8 (4.6)
1996 Land Rover Discovery V8 (4.0)

I presume there is nothing stopping you from use "plastigauge"(spelling?) and fit the primary case with the gasket in place, remove and then measure the thickness of the plastigauge.

I've never used it or even seen it, but it is just a little plastic strip, and as its squished it gets wider. You then compare the squished piece to a special tool which tells you the clearance depending on how much its squished.

I could be mistaken though as this was only explained to me as the way to check bearing clearances on cranshafts

Well!
Engine is now removed from the gearbox and I appear to have no damage to the idler gear or idler gear spacers or casing.
But when I reassembled the clutch housing onto the gearbox and tightened up the nuts and bolts I discovered I have NO clearance for the idler gear to the point where it was locked solid
So what to do next?
The gearbox looks to be OK with no play in the bearings and I will check the synchro clearances tommorrow night but I am now thinking I have found the problem and I have no need to dismantle the gearbox, BUT I always have a small voice saying "pull it apart any way and check". BUT as previously stated the gearbox was good prior to my last engine rebuild and it has probably only done about 5000 miles since a major rebuild of most parts.
So I think I will check what I can without dismantling the gearbox and spend my time searching for the old style orange clutch housing gasket.

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1969 Cooper "S"
1967 Mini Deluxe
1973 Clubman Van (the fleet spare)
1978 ex 1275 LS ("Wizard" Eaton Supercharged)
2015 HSV GenF GTS(occasional drive & tow car)
2019 MINI F55 Cooper S

These gaskets are often thinner than the originals.
If you can't get an original gasket, you need to either change an idler thrust washer, or get one surface ground- to the thickness you need.
These washers are NLA new it seems.

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DrMini- 1970 wasaMatic 1360, Mk1S crank, 86.6HP (ATW) =~125 @ crank, 45 Dellorto (38 chokes), RE282 sprint cam, 1.5 rockers, 11.0:1 C/R.

Im thinking of 2 x black gaskets = 1 x orange gaskets.
But obviously I need to do some home work prior to reassembly.
Plus tidy up the engine bay and a few other small jobs.

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1969 Cooper "S"
1967 Mini Deluxe
1973 Clubman Van (the fleet spare)
1978 ex 1275 LS ("Wizard" Eaton Supercharged)
2015 HSV GenF GTS(occasional drive & tow car)
2019 MINI F55 Cooper S

I think I had the opposite problem too thick gasket = too much clearance
I managed to get a thinner one. The mini king John may be able to help you, 2 gaskets is not the right way to go methinks

I had this happen - took me a while to work out the gear shaft was just - only just hitting the bearing retainer circlip instead of going through the middle of it - the little ears may need a good push down or a tickle with a file.

Dosen't look much but those tags with the holes on each end of the clip were encroaching enough into the line of the shaft for it to hit and be stopped by them.

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David L


My greatest fear in life is that when I die my wife will sell my Mini and tools for the price I told her I paid for them!

Michael,,, you shpould be able to sort it via "One" thicker gasket,,, have them measured & fit them up & use feeler guages through the primary gear hole & into the idler gear--?> case to measure the end float

But,,, Wombat,,, if i am right in what i`m thinking with what you have just said,,, then maybe you should rip yours apart too,,,, if you have a short shaft idler gear fitted into a long shaft type case,,, the you had better rip it back out & fit a long shaft idler gear

was the idler gear that you used the same length shaft out each side??? o one side longer than the other???

& is the bearing in the gearbox case "recessed" into the case about 10mm??? (IE: not flush with the outside (thrust surface) of the case?????

This is most important David,,, i really don`t want to hear about a pre-mature distruction of your idler assy after all that work you`ve done & all that time you`ve put into it

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No offence intended here but--> anyone writing a book about minis 30 years ago may not have experienced such worn or stuffed-with components as we are finding these days.

You should put your heart & soul into everything you do.

ah,,, wrong circlip then?

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No offence intended here but--> anyone writing a book about minis 30 years ago may not have experienced such worn or stuffed-with components as we are finding these days.

You should put your heart & soul into everything you do.

Supplied by reputable Mini dealer as the correct part, - took to it with a file and flattened the tags a bit.

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David L


My greatest fear in life is that when I die my wife will sell my Mini and tools for the price I told her I paid for them!

So you do have a long shaft idler then yeah?

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No offence intended here but--> anyone writing a book about minis 30 years ago may not have experienced such worn or stuffed-with components as we are finding these days.

You should put your heart & soul into everything you do.

Yep (and in case you're wondering - I took the clip out to file it - didn't want filings in the bearing )

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David L


My greatest fear in life is that when I die my wife will sell my Mini and tools for the price I told her I paid for them!

circlip looks to be the wrong type? The one I have does not have the little "wings" and needs to be prized out with a very small screw driver.

And thanks for all of your help and ideas.

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1969 Cooper "S"
1967 Mini Deluxe
1973 Clubman Van (the fleet spare)
1978 ex 1275 LS ("Wizard" Eaton Supercharged)
2015 HSV GenF GTS(occasional drive & tow car)
2019 MINI F55 Cooper S

minor revival -

I've got mine apart and discovered that I had put a thinner gasket in back in March and didn't check the end float. There is a little bit of damage to the transfer housing. I took it to work today and milled the teeniest bit off it to make it flat again - it might work

I took the inner bearing out and KC are sending me another one, didn't arrive today so I haven't checked the end float properly. I assembled the casing with a new gasket minus the bearing and the idler gear flops around too much to measure accurately (or at all)




I was going to ask this very question Matt - I was looking for idler gear thrusts and took the idler gear out of my old Mini K (4 synch) box to pinch them, and discovered the idler gear's shaft is short on both sides. My dad's friend built it for me when I was 18, and it's got a thick washer between the inner circlip and the bearing, to space it outwards - dodgy pr*ck... (it didn't do any damage tho, not that it did a lot of work, synchros were rubbish)

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did I tell you that I won a trophy?