smoothcase/ribbed gearbox

[estepona1999]

Can someone tell me which is the better to be fitted to a 1098 engine and a 3.9 diff,would it be a smoothcase gearbox or a ribbed box? the engine has been tweeked. I read somewhere that the smoothcase box was a stronger box,I would like to know which is the better one please.

[bmcecosse]

Quite the reverse -the smoothcase is poor weak thing........

[philthehill]

Even the standard 1275cc Midget/Sprite box is not that strong when mated to a 'tweaked' 'A' Series having had one fail on me whilst road testing a MG Midget Even the SC/CR Midget/Sprite box failed on me when asked to deliver anything over 100bhp. The solution fit a Ford RS 2000 or Ford type 9 gearbox. Both are good strong boxes with the bonus of synchro on 1st gear .

[bmcecosse]

But certainly not necessary for a slightly modified 1098... The rib case will be fine.

[estepona1999]

thanks for that,I will use the ribbed case box.

[ampwhu]

I have the original 803 box (smooth) fitted to a 1275 engine. I have covered 1000,s of miles without a problem.

if you drive the car properly then it will be fine.

[katy]

if you drive the car properly then it will be fine.

Ditto

[philthehill]

Whilst the 803cc smooth cased gearbox may be alright when driving with a light right foot. When driven in a normal manner the margin between alright and failure is narrow. When mated to a 1275cc engine I would consider that margin to be even narrower. The 803cc engine only gave out 30 bhp at most and the 948cc 37 bhp. The Marina 1275cc (HC) gives out torque of 69lb ft at 2500 rpm max and the MG Midget 1275cc engine gives out 65 bhp max (all figures from Autocar road tests) So you can see from the figures quoted that an 803 cc gearbox mated to a 1275cc engine does need a very light right foot. Fitting the 1275cc engine has nearly doubled the power needed to be transmitted by the 803cc gearbox.
If it suits you to have the 803 cc gearbox mated to the 1275cc engine all well and good but I would be always thinking in the back of my mind is it going to fail?

[ampwhu]

regular oil changes and a 3.9 diff lets me cruise at 70mph without hassle.

if I want a car that does 0-60 in under 10 seconds then I use my Mercedes. when driving my split screen, I poodle around town and then put my foot down on the motorway.

[Chipper]

Whilst the 803cc smooth cased gearbox may be alright when driving with a light right foot. When driven in a normal manner the margin between alright and failure is narrow. When mated to a 1275cc engine I would consider that margin to be even narrower. The 803cc engine only gave out 30 bhp at most and the 948cc 37 bhp. The Marina 1275cc (HC) gives out torque of 69lb ft at 2500 rpm max and the MG Midget 1275cc engine gives out 65 bhp max (all figures from Autocar road tests) So you can see from the figures quoted that an 803 cc gearbox mated to a 1275cc engine does need a very light right foot. Fitting the 1275cc engine has nearly doubled the power needed to be transmitted by the 803cc gearbox.
If it suits you to have the 803 cc gearbox mated to the 1275cc engine all well and good but I would be always thinking in the back of my mind is it going to fail?

Agreed, when I fitted my 1275cc MG Midget engine to my Traveller at just past the 100,000 mile mark (because the original 1098cc was rather tired), the standard 1098cc ribbed-case gearbox packed up shortly afterwards. It then broke a halfshaft and a recon replacement 1098cc gearbox within a short space of time, until I was finally able to fit a matching 1275cc MG Midget gearbox, which touch wood, has been fine since.

[estepona1999]

Thanks everyone for your comments,I will stick to the ribbed box,so anyone want a good cheap smoothcase box?

[darren1camper]

I have a midget 1275 engine, clutch and gearbox. Any ideas how I modify the clutch fork to work with the minor pedal, I do not have a hydraulic clutch. Thanks for your help.

[Chipper]

The clutch fork unbolts, and you can swap in the standard Minor item. I wouldn't recommend using the standard linkage though; the Midget diaghragm clutch is very heavy to operate, and will give a snatchy on/off action, and wear out the linkage bushes quickly - far better to fit a hydraulic actuation setup (they use standard classic Mini slave cylinders).

Complete hydraulic clutch kits are available from Minor specialists for around £100, which may seem alot, but they give a lovely smooth, light, progressive action.

[IslipMinor]

the Midget diaghragm clutch is very heavy to operate, and will give a snatchy on/off action, and wear out the linkage bushes quickly

That has not been our experience.

Since the restoration 16 years and 50,000 miles ago, we have had a 1275 diaphragm clutch on our 1380 with completely standard Minor mechanical linkage and it works very smoothly and easily. The cover plate is standard 1275 Midget and the driven plate a combination of Midget outer and facings, with the Toyota 21T spline for the T50 primary shaft. There is no restraint fitted at the rear of the box, and there is no judder forwards or backwards.

[Chipper]

Ah yes, but is this on a track-day/race car? I found that when I first fitted my Midget engine/clutch with the standard linkage, it had a rather sharp action, making driving in heavy traffic something of a chore.

It also wore out the linkages quite rapidly, in fact, it left me stranded in London one time, and I had to leave the car on my grandmother's driveway for a few days until I could get around to fixing it.

[IslipMinor]

The main use of the car is very much ordinary motoring, including being part of the Lord Mayor's Show parade at less than walking pace for an hour or so!

The only part of the clutch operating mechanism that has worn in the 16 years with the 1380 engine is the 'Rod - Relay to Engine Lever', that connects the mechanism to the clutch operating arm, and that was very recently.

Seems like quite different experiences?

[Chipper]

Indeed. I can only assume that your larger 1380cc engine's extra torque and your 5-speed gearbox may have some bearing on the driveability in traffic and clutch action...