1275 engine/box - what clutch mechanism ?

[jameswallace]

Hi,

I'm currently wondering whether to change my 1098 and related gearbox for a 1275 set up. But am wondering what I might need to do with regard to the clutch mechanism - do I need a hydraulic set up with the slave cylinder or can I get away with just the same 1098 mechanical clutch pedal set up ? Would the clutch be a lot more fierce without the hydraulic set up ?

Any advice on this would be greatly appreciated, and anything else with regard to this upgrade would be useful.

Jim

[aupickup]

1098 box and 1098 clutch works fine, HAD THIS SET UP ON A VAN AND IT WORKED VERY WELL

[bmcecosse]

1275 engine can be fitted with the flywheel and clutch etc from your 1098 engine (some hole drilling involved - but it's easy enough to do) and then it just fits on the 1098 gearbox. I'm in the middle of doing this right now - well I'm actually building 2 x 1275 engines - will then decide which one to fit - but I have done the flywheel hole drilling - took about 20 mins. I believe using the Spridget hydraulic set up (which obviously involves quite a bit of work) results in a fierce clutch. Using the 1098 flywheel/clutch seems the way to go - just don't expect it to deal with mega power and wheelspin starts - which will only break the half-shafts anyway!

[jameswallace]

Oops, sorry folks,

I think I worded the question wrongly - I'm looking to fit a 1275 engine and 1275 gearbox together - would the current 1098 clutch mechanism fit the 1275 gearbox and if so, would it work smoothly ?

Jim

[bmcecosse]

Well -which 1275 gearbox ? The Spridget box is virtually same as 1098 box - except it's rigged for that hydraulic clutch (and has reverse light switch!) but that can be changed to the 1098 mechanical operation which is much easier in a Minor. If it's the Marina/Dolomite box then lots of problems - not a good idea!

[jameswallace]

[quote="bmcecosse"]Well -which 1275 gearbox ?

It's the Spridget gearbox - how can I adapt the conventional clutch mechanism for the 1275 box ?

Jim

[bmcecosse]

Basically - transfer the bits from the 1098 box. if you sit them side by side you will see what's involved. But - don't think you can then use Spridget clutch/flywheel - need to fit 1098 flywheel. Or just use the 1098 box - and sell the 1275 box - seem to get good money on ebay!!

[jameswallace]

ok, that sounds hopeful, it looks like I'm coming around to trying this option. What about exhaust - can I use the current 1098 stainless steel exhaust ?

Jim

[bmcecosse]

Well - you 'can' use it - but obviously it's going to be a bit small to handle the additional flow - especially as it was designed for the 948 engine - and not changed/enlarged when the 1098 came along. Been various threads in the past - attempts to get suppliers to do a run of larger bore systems at fair price. My plan is to use the larger bore ex manifold from 1275 Marina - and I have a Marina down pipe to fit that - and then I will just fabricate something from various bits I have in stock!

[aupickup]

u can buy large bore exhausts to fit

[jameswallace]

u can buy large bore exhausts to fit

Can you say where ?

[bmcecosse]

And does it fit the larger Marina manifold - or just the normal Minor/Mini manifold? Better still of course is the double exit Mini/Ital manifold - is there an exhaust for that - or even better - a proper LCB manifold!

[bigginger]

the double exit Mini/Ital manifold

Mini? How would you make a mini manifold work, then? I ask as I have a Maestro double pipe one knocking about.

[IslipMinor]

All you need for the 1275 clutch to work with the standard Minor mechanical set up is to replace the clutch release arm from the hydraulic operation with the standard one from a Minor. The gearbox front cover, carbon thrust and clutch remain from the 1275.

The operation is not at all fierce, and has worked with my 1380 very well indeed (has a Toyota 5-spd box, but the release operation is standard Minor mechanical with an uprated 1275 clutch).

The exhaust is a large-bore LCB (Maniflow I think) with a 2" o/d system using Jetex universal components from Demon Tweeks. The only 'mod' is the over axle part that needed a short section taking out from one side. Other than that, all off-the-shelf parts. In 9 years have had to replace the over axle part only (once).

[bmcecosse]

Ok - I had assumed that if the mech release arm was fitted - then 1098 clutch should be used. But if Spridget clutch is ok (it's smaller diameter isn't it ?) then that's great!
Later Minis and Itals had twin outlet exhaust manifold - but don't think anyone makes a suitable pipe designed for the Minor to match this - of course Mini/Ital pipe could be butchered sorry 'modified' to do the job I suppose.

[Bazzalucas]

For what it's worth, I just finished installing a complete Midget 1275 & 'box combo in my '58, using the mechanical clutch operating setup, and the action is indistinguishable from the 948 with smoothcase that came out.

[Packedup]

And to add to teh dragging up of an old thread - The Midget box has the same case casting, but stronger internals. The input shaft has the same splines, so the Minor clutch will fit as will the 1275. The pressure plates are different, so you fit the mechanical linkage fork and use the 1275 flywheel and clutch plate, or you drill a 1098 flywheel and use a heavier pressure plate that gives less grip! Sticking the the 1275 set up results in less rotating mass, *and* more bite.

My Minor has a 1275 with a 1098 flywheel/ clutch in it, and though it had a new clutch kit last year it definitely feels soft. As does the one in my Midget, which is a 1098 engine and so 1098 clutch - And that engine is completely rubbish! To me it's obvious the best option is to use the best clutch, which in this case has less inertia and more grip.

Though I'm still on the hunt for a 1275 Midget flywheel if anyone has one left over from going the less sense way

[bmcecosse]

Well - many say the Midget clutch is harsh - but it's not something I have tried. Remember in the Midget it has much less weight to move - compared to a fully loaded Minor. As far as i know there is no internal difference in a Midget gearbox - just the reverse light and the hydraulic clutch arm. Maybe it's only harsh when used hydraulically in a Minor ?

[Packedup]

Well - many say the Midget clutch is harsh - but it's not something I have tried. Remember in the Midget it has much less weight to move - compared to a fully loaded Minor. As far as i know there is no internal difference in a Midget gearbox - just the reverse light and the hydraulic clutch arm. Maybe it's only harsh when used hydraulically in a Minor ?

The ribbed Midget box has far better bearings and can take a lot more punishment than the Minor version. Not all Midget boxes had the reverse light switch either! I think reverse lights came in around 69, they were certainly a mk3 feature not a mk2.

I don't know about the harshness of the 1275 clutch, only that the coil spring 1098 one is barely up to 1098 Midget power let alone 1275 power. When testing the handbrake on my Minor (1275 Midget engine, 1098 clutch which was replaced under a year ago) I found my foot totally off the clutch in first with the car not moving and the engine running!

On the bright side, I suppose a slightly softer clutch is a little kinder to the drivetrain when driving "unsympathetically" ;)

[IslipMinor]

The internal difference in a genuine Spridget gearbox is that the mainshaft gears run on needle roller bearings instead of phosphor bronze bushes. The rest of the bearings are identical to the Minor/A35 etc. Originally it used a heavier duty layshaft spindle, but that was standardised across all the boxes, and became the only one available as a spare.

Again in a genuine Spridget box the ratios are closer for 1st, 2nd and 3rd.

Externally, apart from the later reverse light, there is no difference.