I have recently fitted a four- speed Crash gearbox to my 28 top hat to cut down on noise and driveability on long trips. Having recently completed a 1600 mile trip around the South island over two weeks I can say this was worth the trouble especially on the way into Dunedin and in and out of Nelson.
A number of interesting things were discovered whilst fitting and fettling the gearbox. The engine was NOT moved forward nor was this necessary despite what has been written elsewhere.
What I did discover is that the gearbox first motion (input ) internal spline on the four speed gearbox is closer to the flywheel clutch- lining.
I discovered this as I could not disengage the clutch completely causing drag and clashing of gears when trying to move off. This was despite careful setting of the clutch levers exactly to specification. I proved that the plate was unable to float away from the flywheel lining by loosening the nuts around the periphery of the gearbox and sliding slotted washers 1/16 " thick between the box and crankcase flanges and re-tightening (the register on the box is plenty long to locate despite this).
The improvement was immediate and astounding The clutch now cleared perfectly and all gears including reverse were selected noiselessly. As I was running short of time and energy before the big trip I left the washers in and the trip was completed without any more problems. I promised myself to do some careful measurements on return to see what the differences were between the early flywheel and the four speed Ruby type engine.
I did this tonight and the accumulated difference is around 1/8 "(3 mm) Yes the flywheel recess is shallower on the early 3 speed cars than the Ruby-Forward starter engine. this applies to the Borg and Beck clutches also. This would explain also why so many owners have experienced clutch drag when fitting 4 speeds to early cars. It is also a very plausible answer to the reason for the blind spline on the input shaft. it was there to prevent mis- matching of parts, the new flywheel depth was required as the input shaft on the 4 speed was closer to the flywheel. Believe the blind spline became standard with the forward starter, 4 speed box and deeper flywheel. The relative position of the flywheel face to the gearbox can also be variable - I have a number of engines here an I have measured a difference of 2-3 mm between them. This is due to manufacturing tolerances and lapping of flywheels to shafts as well as positioning of the front main bearing thrusts.
I hope this is useful information-Cheers Steve Hainsworth

Location: Wellington New Zealand

Steve your trip sounds wonderful - very jealous, will we get to see photos?

I too have fitted 4 speed boxes into 3 speed cars without issue or the need to move the engine.

I have several 3 speed boxes with blind splines, suggesting it was introduced prior to the 4 speed box.

I am aware that the splines vary in length on centre plates (see below,) the shorter may may have helped your clutch problem, then again, maybe not!

The issue of clutch plate clearance has come up in the Austin Ten Drivers Club.
If memory serves, the cause was that newer clutch linings are made to a thicker specification than original.
The answer appeared to be fitting spacing washers of appropriate thickness between flywheel and the clutch cover plate.
Steve V.

Location: Polegate, East Sussex, United Kingdom

I agree with Ruairidh that trip sounds great, anybody in NZ willing to loan a 7 for two or three weeks ?. Seriously !!

Location: Oakley ,Hants

I have found similar clearance issues with the nose of 4 speed boxes and clutch plates even in later engined cars. It has to be a common but possibly often undetected issue, just look at how many blind spline clutch plates show signs of wear on the rivets.

Derek, I may not be able to supply a car for 3 weeks, but if visiting these shores and wanting to meet a few A7 owners please do get in touch. PS this is an open offer to any other forum members wishing to sample the delights of Aotearoa.

Location: Auckland NZ

We took 7 weeks to drive the South Island.
No where near enough time.

Location: Wessex

Hi,thanks for the feedback. I dont think shortening the splines is the whole answer as I believe they can also suffer from the nse of the first motion shaft touching the spherical boss at the plate end, this may need relieving also. Now that the problem is known I guess some trial and error assembly will cure it on an individual basis. The comment about some 3 speed boxes having the blind spline makes me wonder that it was introduced at the time the 1-5/16" crank was introduced which necessitated the new flywheel.
With regard to the loan of cars in N Z is concerned I doubt it would be a problem, (some of us have multiple cars ) but it would need to be planned and to make it worthwhile, guided by the locals. The South Island scenery is Breathtaking as Ian would allude to and the 8 weeks he mentioned would be needed if you wanted to see everything, but 3-4 weeks would be realistic to see the best of that Island. My preference would be a maximum of 4-5 cars maximum to make the trip manageable . Needs to be done February March for best weather and fewer Holidaymakers on the roads. It all depends how much time and money you have to spend ,some of us ,like me, still have to work !

Location: Wellington

Location: Wellington

Your trip sounds wonderful!

I established some time ago that the blind spline serves to stop the sliding element of a splined shaft from seizing up under load. It was common on gearbox input shafts well into the 80's on Ford and BL cars, probably many others aside.

Stuart

How does this work?

Not sure that it is a problem on an early Austin 7 - the splines are not under load when the clutch is disengaged and surely this is when you need the splines to slide.

Never noticed any difficulties with my 28-29 cars - all with full splines into a three speed gearbox.

Tony.

Location: Malvern, Melbourne, Victoria, Australia.

Having driven 3 and 4 speed cars I found that they both suffer from too big a gap between top and second or third and the only benefit of a 4 speed gearbox is to be able to climb up the side of a house. When I rebuilt our RN 20 years ago I looked at fitting a 4 speed box on the proviso that it had close ratio gears. Andrew Bird provided an excellent set for heavy saloons and a friend, who runs an RP saloon, commented on the improvement in performance. However the conversion, which left the engine in it's original position, involves a lot of work so for the other car I fitted Andrew Bird's higher ratio 2 gear to it's 3 speed gearbox, which I find to be almost as good. All of my 3 speed boxes have blind splines and I've only had one centre plate without blind splines and the splines were badly worn.

I fitted an 1-5/16" crank engine to my 1929 car. I used the forward facing flywheel that was lightened and modified to take the earlier rear facing starter.
On first assembly I had the same problem with the clutch binding.
I found the difference in length of the splines on the centre plate as mentioned above. Fitting one with the shorter splines cured the problem.
However I also did a bit of measuring and think that the later flywheel is a bit thicker so that the clutch lining ends up a closer to the gearbox aggravating the problem.

Location: Melrose, Scottish Borders

I have had fun as I have just fitted a 4 speed box to my Rosengart (essentially a 1927 short wheel base Austin ) using the Rosengart clutch assembly withs a splined plate and Rosengart thrust race set up, good fun linning that lot up. to do so I had too move the cross member back by 3/4", make new front brake cables, make a new handbrake anchoring point, shortened and fitted a Hardy spicer prop ,Hardy spicer to Rosengart adapted plate and new steel tunnels. Was it worth it, yes you bet. I still have all the removed components ready to refit if required.

Location: Oakley ,Hants

Like Dave I have fitted one of Andrew Bird's high ratio second gear sets.
It is excellent and allows easy running at 30mph in 2nd and can take it up to 40 when needed.
In addition the top gear dog is modified so that the change from 2nd to top is much quicker.
The slight downside is the wider gap between 1st & 2nd so that I have to use 1st a bit more and it's a bit more difficult to judge the revs changing into 2nd.

Location: Melrose, Scottish Borders

Stuart and Dave,

Still no explanation as to how the blind spline stops the splines from wearing-is it because the wider spline is stronger- seems unlikely.

I would have thought that spline wear was caused by lack of lubricant- a bit of graphite or moly grease on assembly.

The wear on a spline joint would be similar to the wear on the roller set in a universal joint - small movements with poor lubrication causing fretting corrosion.

Tony.

Location: Malvern, Melbourne, Victoria, Australia.

Tony

I believe the idea is that the extra strength of the blind, or master spline,stops the deflection caused by torque in a uniform size of spline, which can cause a spline to lock up under high torque. I wish I could find a published reference to back this up, unfortunately, I cant! However I do remember being taught this as an apprentice motor mechanic 35 years ago.

Stuart

PS If anyone has engineering theory books, maybe they can find something in them?

Stuart,

Mrs Google only brings up the use of a blind or master spline to ensure re-assembly in the original position.

Possibly Longbridge designers decided that a worn spline was best re-assembled in the original worn position to get best tooth support.

Tony.

Location: Malvern, Melbourne, Victoria, Australia.

Photos from Steve's NZ tour:

















A 1924 Chummy that was discovered en-route...















Now Steve, do you have any of the lovely scenery that I hope you saw on the tour, please?

Steve - how well I recall that Chummy. At Nelson during the 1972 International V & V Rally, friend Roy Hicks (now long deceased) and I as '25 owners, were discussing something about the chassis number of the car. We couldn't find the custodian to seek permission to lift the bonnet, so I suggested I crawl under the car and check the details stamped into the rear cross member. Rather surprised when, without asking me what I was up to, the returned owner had grabbed me by the heels and dragged me out! No chance to find out what we wanted. One of life's embarrassing moments. Your car still looks great - I hope other Friends noticed what a rare model it is. Cheers, Bill in Oz

Location: Down Under

Being upside down appears to be very good news for the curing of oilt oil leaks.

Location: Wessex

Thanks for Posting these R. I loved Bills story of the 24 chummy- Perhaps the Owner thought him a vagrant having a nap- or stealing his speedo drive mechanism !
I was fortunate that the Guardian of the Yellow chummy was the brother- in- law of our host in Dunedin and he allowed me free range with my tape measure to check dimensions for my 25 chummy rebuild. The car belongs to the Otago AA and is housed in a transport museum. Another 25 AC bodied car is owned by the Otago Car Club.There is also a 23 scoop scuttle car in Invercargill (one of 3 in NZ )
There are more and better photos that Damon Rose took on the trip of scenery and me in compromising situations ! I will try to get these to you to post.
Bill I still have the Oil guage for you , will send it off when I get sorted-Cheers Steve.

Location: Wellington

Your car still looks great - I hope other Friends noticed what a rare model it is. Cheers, Bill in Oz[/quote]

Yes, as Bill says, Steve's saloon is indeed a rare car. The side photograph shows how it differs from the " normal " narrow door saloon.
Front mounted headlights, higher nickel radiator, scuttle vents, roof covering stretching from the peak right to the rear, the clasp body join in the rear wheel arch area and particularly the plain door with no beading and with different radii on the bottom edges
Further changes are the fitting of a coil engine, the dashboard with side pcckets and a flat steering wheel.
See page 187 in Purves's Source Book for more information. ( The car illustrated now has the radiator correctly plated + coil engine )
Why Austin's introduced this short lived model is a mystery. It cannot have been to use up unwanted bodies as they differ quite a lot from the previous R one. It appears they were being built at the same time as the RKs and this seemed to give Austin's a problem - everyone wanted the new RK model! Unable to sell them they appear to have shipped much of this unwanted stock to New Zealand, and possibly other areas, although not Australia.
Currently in NZ there are about ten examples, the largest concentration, but in the UK I know of only three and with one in Holland.

Location: Melton Mowbray

Steve writes:

Hi R,
When I received this from Dunedin the other day I thought you would love to see it also.
Dick was with us on the Trip down south ,but left us in Alexandra near Cromwell to do this Trip. Dick stopped off here last night and gave me permission to forward this and some extra photos which show the wonderful scenery we drove through.
Dick flew Sikorski Helicopters in New Guinea for many years then Did heavy logging with Russian helicopters on the west coast before retiring. He is also great company and a wonderful and clever friend.
If you could post them on the Friends site I am sure it will delight others also.
Cheers Steve Hainsworth

To return to dragging clutches if I may, I found that on reassembly I could not persuade the clutch to disengage. As far as I could tell, all clearances for the fingers were correct and the throw of the release bearing was adequate. Keith found that the new nut he had fitted to the flywheel had rather proud corners which interfered on the inner edge of the hole in the plate. A touch with the flap disc on the grinder relieved the pointed corners and this allowed the disengagement on the bench.
Back in the car there is still a crunch when stationary, slightly relieved by engaging reverse before heading for first or second. It may be my technique but I've found I can only engage a forward gear by a very positive snick into gear. Any hesitation creates a crunch.
I was tempted on reading the previous posts above to fit spacing washers between engine and gearbox but I can't see how they would improve the action as this would put the release bearing further from the disengagement point and so not free the clutch components from each other?
I'd appreciate further opinions on this...

Hi duncan,
The washers will allow the plate to float back from the flywheel into the splines by about a sixteenth of an inch. I found that the plate was rubbing on the flywheel linings as it was unable to go back any further on the splines. It only takes half a hour to make and fit the washers and is well worth it to cure the crunch going in to gear. Please let me know if it cures the problem-Cheers Steve H

Location: Wellington New Zealand

Thanks for that explanation Steve. When Keith was looking at the clutch he noticed that the splined nose was a short one, perhaps from a Chummy so I wonder if the problem is somewhere else…
However, the spacers will only take a short while to make and fit and it may be worth a try. I will report back.

Location: Ripon

Are you certain the lock washer on the rear crankshaft nut is not touching the centre plate?

I always trim anything that protrudes outside of the nut ,once the tab has been turned up, with a sharp chisel.

More pics! Apologies to Steve for mixing up the annotations!


Clutha River From Helicopter



Access Road to Piza Range



Benmore Hydro Station on the Clutha River( N Z s Largest-Supplies the Aluminium smelter at Bluff and North Island. via Cook Strait cable)



The entry road



Wonderful road !



This is a ski-field in Winter and That’s Mt Aspiring I think near the Glaciers ( Fox and Franz Joseph )



This is 4 Wheel drive only unless you have special permission!



Shades of the Lake District?



Rocky Mountain high (4000 ft)



Thats The Clutha Down There !



Now what Do I have here!



Cool car this, Pressure fed Phoenix Crank, Vince Leek step up gears, goes really well




Picking his way down





First gear most of the way



Rock Star



Gently does it !









Time for a dip on the way down



It ‘aint ‘arf ‘ot Mum (32 degrees )

Duncan,

Re the 'graunch' when engaging first- possibly not the same as your problem but in my cars (three speed), quickly engaging first gear always causes a nasty crunch when starting off in traffic with no time to let the plate stop spinning.

Tony.

Location: Malvern, Melbourne, Australia.

Steve,
I've just fitted 1.6mm thick cut-open washers between the engine and gearbox and the clutch now frees better than it has ever done. As soon as it stops raining and all the salt has gone I can give it a road test to ensure that it still bites without slipping.
I like this forum me!

Location: Ripon

Hi Duncan ,
Thats good news ,It wont slip as you have not altered the compression on the springs. It is likely that a permanent fix will be able to be done by allowing the plate to move back more by relieving the spherical end of the boss in front of the splines and making sure the plate is not bottoming out in the gearbox nose splines.
cheers Steve H

Location: Wellington New Zealand

I'll leave that tweak for later. I've had the engine out and in three times in the last few weeks and don't want any more practice at that! I did think of making an ali spacer but your suggestion is probably more appropriate as a better cure.

Location: Ripon

Just to add to this old thread, having just taken the engine apart for a re-build, putting it all back together, the clutch would not properly disengage, even though I put it back all as before...

So, took it all apart for a second time, and dismantled the clutch and there was the typical wear to the fulcrum pivots, the lever contact points and the pivot rods, so I ordered new parts (came the next day!) and fitted, comparing old with new and there was quite a bit of wear.





Re-fitted it all and despite the new parts, the same problem!

Took apart again, and this time, I repaired the wear to the fulcrum pivot point on the clutch/flywheel cover, using the grub screw method (I used cut-down bolts) and I set these slightly proud of the original "trough".

Re-fitted it all again, same problem!

Took apart again, and this time, cleaned the clutch withdrawal plate (someone had spray painted the assembly when the new linings were fitted (in 1977, first used in 2015!), the paint film had a couple of runs, which may have prevented full compression, so cleaned back to bare metal. I also noticed that there were washers fitted to the clutch cover in the spring housings, I hadn't spotted these until one fell out, these were about 2mm thick and would have the effect of making the springs stiffer, so I whipped these all out.

Re-fitted it all again, same problem! That was yesterday.

It was only last night, reading this thread about inserting spacers between the crankcase and the gearbox, that I thought I would give this a go, which I did this morning. I cut washers to insert over the studs between the crankcase & the gearbox, I used the discarded washers from the clutch cover!

Hey presto, the clutch was working properly, all gears engaged silently, not a single crunch, indeed, gears can be selected on part depression of the pedal, a significant improvement, but what had been going on with my clutch?

I think previously, before being disturbed it was just about working properly, reverse often grumbled and the odd occasion I used 1st, it would give a "clang" as it went in, anyway, I had a close inspection to see what the problem was.

My first thought was that the spline input shaft was bottoming out within the gearbox, but no, there is a good 5mm clearance, so this was not the problem. It was then that I noticed that the boss for the clutch withdrawal spring was shiny - it was the rivets to the clutch plate itself that was in contact and it was this that was preventing full disengagement.



As I have had the gearbox in and out so much over the past 5 days I am going to leave matters as they are for the time-being, I am planning on stripping down the gearbox soon, so it can wait until then, my options will be to either grind the rivets down (I may buy new and get a blacksmith to fit these as I do not wish to weaken the fixing), or make up a single spacer for the contact area between the gearbox and the crankcase.

I am guessing that perhaps the new linings (in 1977!) are thicker than the originals ever were, which would mean that the clutch plate is further rearwards, the difference between working and not working is minimal clearance, so anything that is slightly different is going to upset the equilibrium, anyway, I am sorted now and it just goes to show the value of sharing experiences!

Location: Saltdean, Brighton