Rosy, a restoration project - Transmission

Now for me the interesting part,  I am now rebuilding the transmission unit out of odd parts I have accumulated so I can mate them to the engine that, if you recollect was also built out of 'odds and sods'.

I have two spare gearboxes apart from the one that was fitted to Rosy, so I selected one to strip and refurbish.  But first I had to fit the flywheel housing to the engine, and the flywheel. Here I encountered the first problem, when Pete had rebuilt the engine he had fitted the sump.  The flywheel housing has 13 bolts fitting it to the engine block, 11 from the front and 2 from the back, so off had to come the sump!


Bellhousing

Fortunately when I had a utility extension built for my wife to the rear of our house I thought what a good idea it would be to extend the garage at the same time, and whilst doing that why not a pit to work under my MG's and a RSJ to act as an overhead beam to fit a hoist to.  What a wonderful idea it was to extend the utility!
It now came into use for the first time in real action, I hoisted the engine unit up to unbolt the sump, I do not know how heavy the assembly is but at least a two man lift.  But now it was a few simple pulls on the chain and up into the air went the engine.  The sump was removed and the flywheel housing fitted.  The engine gasket set that I had acquired over the years had mainly been used up on the engine rebuild and fortunately I had remembered where I had kept the spare gaskets.  As usual the appropriate gasket did not fit at all well and some modifications were called for, eventually it was made to fit.  This has taught me a lesson, after all the trouble making it fit, it would have been quicker to have made my own, buy a sheet of gasket material in future!


Clutch

When I removed the clutch and flywheel assembly off the original engine I was perplexed by a circular ring of what appeared to be a cork gasket type build up around the inside of the flywheel housing.  I realised what it was, it was a mixture of the worn clutch corks and oil that had been thrown centrifugally on to the inside of the housing, so it was not a problem.

The flywheel was now fitted to the end of the crankshaft and the bolts wired for security, it would not do for one of them to come loose at high revs.  Now the next item to fit was the clutch assembly.  I had acquired a re-corked clutch somewhere in the past and that assembly had to be assembled and fitted to the flywheel.  Trying to fit the horseshoe shaped circlip over the spigot, whilst compressing the three springs began to tax my patience, to make sure it could be done I tried assembling it with the old, worn, clutch and it proved easy to do.  However the new clutch being that much thicker was not letting me compress the assembly enough to fit the circlip.  On inspecting the centre drilled into the centre of the crankshaft, I realised there was a plain diameter that I could tap " BSF and using the threaded wire I had from clamping the road spring assemblies together, I screwed a length in and with a nut and washer fitted I compressed the assembly easily and was then able to fit the circlip.

( I was later to discover that reason why it was difficult to fit the circlip, the re-corked clutch plate was 1/2" thick instead of 3/8".  see 'My Apologies' further down this page.)

I had assembled the remote assembly ready to fit on to the gearbox when that is rebuilt and I have yet to fit the bell housing to the flywheel assembly.  I had fitted the thrust bearing and washer without consulting the manual, big mistake, fortunately I noticed looking at the assembly drawings in the manual that the thrust washer goes behind the thrust race, not in front of it as I had fitted it.  Another little job to rectify in the near future, but at least I have nearly got a transmission unit to fit into Rosy!


Shaft for clutch lever

The other job I have to do is replace the shaft that the clutch operating lever goes on, when I stripped it down I read that there was a taper pin securing the lever to the shaft.  When I tried to punch the pin out I realised the punch was hitting hardened steel, i.e. the shaft itself.  When I realised the pin was not fitted I commenced to lever the clutch lever off the shaft, in doing so the shaft came out with the lever.  The reason for this is that at some time the shaft had sheared ( see photograph left ) but it had not stopped the clutch from operating, fortunately for the previous owner.

Rear engine mount
Rear engine mount.

Having now assembled the complete transmission unit I came to finally fit it on to the chassis, using the block and tackle and my trusty RSJ overhead I lifted the unit and lowered it on to the frame mounting brackets.  It is not possible to get the TA type front engine mounts anymore so the TC type one is used.  I found one of the differences between the two is that the hole in the frame-mounting bracket is too small and needs to be opened up to 28mm.  Off came the brackets to modify them, this done I replaced them and once more attempted to fit the unit.  Everything went well until I had to work out which side of the rear mounting brackets the gearbox half of the engine mounting went.  This goes to the rear and is clearly illustrated by the photograph on the right.


Click for a bigger view of clutch assembly

Finally the transmission unit was fitted and "Rosy" was beginning to look like a car, however after I had fitted the prop' shaft and the transmission tunnel to fit the floorboards, I then came to connect the clutch operating lever.  Here I found a major problem; I could not remove the excessive amount of free play in the clutch pedal.  What could be wrong?  I spoke to several colleagues about the problem and got nowhere, they had either had the clutch assembly apart too long ago to remember or they had never met up with the problem.  They had probably kept meticulous notes when they stripped theirs down and re-assembled it going by the notes they had made and not the diagram on the left taken from the workshop manual.


My way.

 


The workshop manual way.

I checked with the spare pressure plates I had acquired and sure enough I was in a quandary!  Two of them had the thrust race washer in front of the thrust race, where I had fitted it in the first place and the other two had had them where the workshop manual showed them fitted.  So I set about removing the bell housing from the flywheel housing to sort out the problem of where they probably should go.  Removing the floorboards and the transmission tunnel (only dropped in position) and easily removed I then found that the instructions in the manual on stripping the gearbox and clutch began to make sense.  When the engine is suitably supported at the rear end, do not forget you are removing the rear engine supports as well!  Having unbolted the bell housing from the flywheel housing, I began to ease the two apart, fortunately I had made my own gasket and had used "loctite" gasket seal between the gasket and the flywheel housing so the gasket stuck to that and was not damaged.

Easing the assembly backwards, I had removed the clutch-operating arm, as this would have prevented the clutch operating fork riding over the thrust race.  Now as the assembly came clear I found out why you have to rotate the gearbox through 90, it is for the rear engine mountings to clear the chassis cross member.  It must be clockwise viewed from the rear, if you try turning it anti-clockwise you will clear the cross member but foul the handbrake assembly.

Now it was free, so I left it suspended whilst I removed the circular nut, thrust race and washer and reassembled them as I had done originally.  (See photographs, "my way" and the other showing how the manual shows it) I then put it all back together.  The two photographs with the battered circular nuts are as I received them as spares, I did not bash the hell out of the locking holes

I now have control over the free movement of my clutch and I am feeling a lot happier, perhaps other TA enthusiasts will ponder over this and let me know the definitive answer, am I right or is the manual right?

October 2006

No one answered the question that I asked as to whether I was right or the manual.  I can now categorically state that the manual is correct!  I was wrong, even though I thought I had control over the clutch, I had still used up a massive amount of adjustment to get it to work.  Not being happy with the assembly I went into a period of inactivity, I was not happy with the clutch and I could not easily turn the engine over, it was too tight.  After some time and consideration I decided I needed specialist help, this I got.  I found one of the rare persons still around who knew old engine rebuilds and the MPJ series in particular.  I asked him if he would have a look at my engine unit and give me his opinion.  To do that he would need the engine over at his place and then he would strip it down and let me know if there were any problems.  THERE WERE!

I think I said somewhere that if you wanted an MG similar to my first one the thing to do is buy one that has been rebuilt, it is a hell of a lot cheaper as I was about to find out!

My Apologies

I hope I have not caused problems for anyone reading my clutch rebuild description.  The reason that I write this is to confirm that I made a mistake on the clutch assembly.  The workshop manual is correct and my assembly is incorrect.  The reason for this is that as indicated by me the clutch lever shaft had broken and had to be replaced.  The shaft I had made was manufactured with the woodruff key way in the incorrect position radially; this meant that the mechanical advantage of the clutch lever was lost.  When the new shaft was made the assembly I thought to be correct, now had to be reverted back to that shown in the workshop manual.  The assembly was also compromised by the clutch plate being too thick, it should be 10mm or if you like 3/8" thick, the one I had acquired was " thick.  With this combination of errors it was no wonder that when I had the engine fitted on the chassis the clutch mechanism would not work, hence my lack of enthusiasm and no update on the rebuild site.  However all this is behind me and once more we can make progress.
For further information on the problems with the engine, go to the engine section.