Friday, 28 December 2012

Very Flat, Norfolk

We can muse over what the oft-quoted Noel Coward meant by this line from 'Private Lives', which premiered at the Edinburgh King's Theatre 1930. However, keen observers and students of geography will know that Norfolk, whilst undeniably low lying compared to some parts of the country is positively undulating when compared to others, notably the fens, at least in places.

Undulating is also a word that could be used to describe Amelia's sump plate, which won't be doing any sealing anytime soon:


Anyone got a spare one?

Wednesday, 26 December 2012

Ever deeper - Coupling Gears and Bearings

Under the guise of clearing out the workshop (I was - I was trying to finish off the primary case polishing, but Mrs H was surfing and wanted some Boxing Day P&Q) I ventured into the shed to retrieve the coupling gear cover.

The idea is that once the coupling gear cover is off, I can polish it and the primary case.

The nuts and screws came out relatively easily, but the cover was a b****r to get off, as we say in Norfolk.

Turns out that the cover has a steel locating sleeve around two of the studs, which corrode and resist the removal of the cover. A few minutes with the hide mallet and a soft drift had it shifted (seized at the front, where the steel sleeve meets the weather).

Anyhow, here it is, off:


No drama there, all present and correct - though I expected the coupling cover main bearing to slide out of its journal and stay on the shaft. The peculiar face-type oil seal is cratered - bits of the seal are completely missing.


Here is the cover, complete with bearing. There is a fair bit of gunge in there, which will be ferrous material from the wear on the gears I expect.

The bearing is in there, and for some reason refuses to turn. The story is that this bearing, which is essentially similar to the other drive side main roller bearings, has a inner race which is 0.001" smaller than the roller bearing in the crankcase, so that the corresponding journal on the crankshaft is also smaller. 

This means that when the engine is assembled, the smaller outer journal (the one for the coupling gear cover bearing) will pass through the main bearing in the crankcase.

This bearing is also lipped on the outside of the outer race. It's not entirely clear why they did this, since the crankshaft is located axially at the timing side.

Anyhow, this went back into the workshop to be cleaned up. It turned out that someone had fitted two paper gaskets to this cover for some reason.

The bearing came out with some gentle persuasion (a hammer and a socket in the time honoured fashion) but a look inside the outer race revealed it was junk:

A massive pit and some odd wear marks in the outer race. There were possibly some wear marks on the inner race as well, but we need to look further before passing judgement on those. 
All in all, a jolly evening's work.


Shock Horror!!!

To get further into the engine, we have to remove the crankshaft shock absorber. This consists of a sleeve splined to the rear crankshaft and hence driven by it. The sleeve has a external spline as well, and a section of it's length which is a plain bearing surface. The engine sprocket runs on this plain section, and is machined with a face cam. The corresponding cam profile is machined onto a further part, which is splined internally and is driven by the sleeve on the crankshaft.

In order for the crankshaft to drive the engine sprocket, and to prevent the face cams from riding over each other (resulting in no drive) the whole assembly is held together by a heavy spring.



Hence if the system is running smoothly, the cams are held together by the spring - but if there is a sudden high torque the cams are free to slide over one another and compress the spring. This thus forms a transmission shock absorber, rather like the rubber cush drives commonly found in more modern machines in the centre of the clutch.



I guess that at the time these engines were designed rubbers were not ably to withstand the heat & oil found in the primary drive.

Anyhow, it is all in pretty good shape, with no evidence of wear anywhere. Even the sprocket is good. It has 25 teeth by the way, just for the record. This strikes me as a little odd - Drags list 26T and 27T sprockets; my '52 Ariel Owners Guide says 24 solo and 22 sidecar; the '51 SQ4 parts book lists 22T, 23T and 24T.

Mr Waller however lists 25T, so it must be OK!

The only thing I could find at fault was the retaining nut, which is pretty mangled and the split pin was missing.



Bracketry

Brenton Roy posted this picture on the AOMCC forum to help out us poor souls restoring Mk 1 Square Fours:




It shows, rather obviously, the top of the oil tank with the breather tower, the filler and a mystery bracket.

I had no idea this bracket was there, but since I have had a mystery hole in the top of my tank I suppose I should have figured it out. Anyhow, it was a simple matter to make one out of a bit of steel strip that was laying about in the bits box:



I'll fill in that hole next time I have the welder out.



Friday, 21 December 2012

Monday, 10 December 2012

Still Cold Outside


So we have to find another job that will  bring us indoors.

I don't have many of those left now, but one thing I haven't touched is the oil tank.

Its the right tank, but it has a number of problems:
  1. The filler neck is bent, and the thread damaged on one side. It looks as though some clumsy oaf has dropped it neck down on a hard floor.
  2. The breather connection is bent, caused by said oaf probably in the same floor-dropping activity. The picture above shows this one, and the filler neck, though I had started work on it when I took this shot (as witnessed by the 38 mm socket acting as a former)
  3. The filter is missing
  4. There is a hummungous dent in the side that is hidden by the battery
The first of these little gems that I tackled was the damage to the filler neck. The bend was on one side and had splintered the crests of some of the thread away from the base material. Looking closely at this I decided that the material must be relatively hard, so I elected to normalise the metal.

Normalizing is the heating of steel to above its critical temperature followed by cooling in air. The piece is usually left somewhere warm. Normalizing is a quick method of softening a piece to the point where you can harden and temper it for use for your chosen purpose.

I used the trusty Rothenberger Superfire 2 to heat the area to bright red, and played the flame at a distance to bring the temperature down as slowly as possible.

Then, using a large socket in the vice, I placed the neck over the socket to use the socket as an anvil. I used a 38 mm socket, which supports the neck nicely and is a close fit.

With the material cooled & annealed, I was able to push the bent neck back into shape with a variety of drifts & chisels. This went very well, which just left me with the thread to fix.

I did this in two stages, possible needlessly. I started by grinding out the damaged part with the Dremel, since it was confined to about 15 degrees of the full circumference and maybe 6-7 pitches. I cleaned it up using a 1/2" CEI plug tap as a chaser.

Looking backward, I could probably have saved more of the original material if I had started with the tap. Still, the cap will now happily go all the way down to the seal!

The next job I had to tackle was the breather tower. I had a very good picture of what this is supposed to look like from (The Ever Helpful) Brenton Roy of the AOMCC.

As you can see from the pictures, the delightful minaret shape of the breather was a pale shadow of it's former self after the short bungee-less jump onto the garage floor, and I was afraid that much grief provided by attempting to cold form it back into shape would:
  • Squash the tube flat
  • crack the material of the 'minaret'
So, I figured some hot work was called for, though at this point I hadn't decided if I might do this with the breather detached from the tank. Holding the tank by the lower mount (so I could pull up on the breather connection) I heated the breather bright red and held the little tube in a mole grip, with a suitable rod (actually a masonry nail).

I found that the tube would move from side to side quite easily once the material was hot enough, and this with some upward pressure was enought to roll the minaret up and out of it's inverted position. A couple of cycles of this and it was back to a very passable representation of it's former self.

Next job: the dent in the side.

Friday, 30 November 2012

Engine Tolerances

Today I have posted a new page, 'Engine Tolerances'. This shows a table of the dimensions and tolerances I am using to inspect the engine, and will build up as I complete the inspection.


I started by measuring the bores. I now know that Amelia's bores are 20 thou oversize, but that they are looking good with little wear.

I've measured up the pistons, rings & pins. The results are shown on the 'Engine Tolerances' page.

In line with a current topic in the AOMCC forum, I will weigh the pistons & pins - though I don't know what I will compare them with! or what I will weigh them with!

Tuesday, 27 November 2012

Back in Charge

As an aside from the engine strip, which is challenging at the moment since Amelia is still resident in the Summer House and the bottom end is in the frame, and there is precious little light to use to continue the engine strip, I have been polishing up the chain case and making the battery tray.

You'll have seen the post Battery Carrier earlier in the blog and you will know that I had no part of the battery carrier originally. You'll also know that thanks to the generosity of the Ariel Owners Club members I have been able to get all the technical details I need to make one.

So, starting with Brenton Roy's drawing, the dimensions of the GU11E battery from an old Lucas catalogue and some 16 SWG cold rolled steel sheet, we could get started.

Using the faithful Bosch jigsaw, I cut an oversize blank just to have something I could handle on the bench. These days, having failed to make myself some engineers marking blue, I mark out using a Sharpie spirit marker before witnessing in the traditional way, with a dot punch.

The next stage was to cut out the shape with the hacksaw. The 'internal' tabs (those that the screws pass through, underneath the battery carrier) I cut out with a piercing saw, starting first with a 1 mm drill at each end of the cut. 

The shape was then finished off with various files.

The holes were then centre punched and drill 7 mm, (clearance for a 1/4" BSCy screw).

The next stage was to fit the nuts. These were 1/4" BSCy full nuts, tacked in place with the trusty MIG, and yes, those holes are noticably triangular - hard to drill perfectly round holes in sheet metal.

The next step was to bend up the tabs. I put both halves of the chaincase in the vice to check the overall width before I did this - I didn't want to end up with the tabs out of parallel or rebending them.

Here is the raw battery tray fitted to the chaincase for the first time. The special fasteners and spacers are from Acme Stainless. It's looking good.

That is about it really. I re-cut all the threads since the welding appeared to have caused a little distortion  I draw filed the edges and deburred, and since this picture was taken I bent up that tabs that retrain the battery. Might be a problem here - I have ordered a battery from Drags but I don't have it yet.

Last thing before assemble was to paint - the usual UPol etch primer, followed by Halfords gloss black acrylic, then final assembly, and that's it. again, stainless parts from Acme.

A few days spent in a warm room saw it packed away in a box until the bike is assembled.


Wednesday, 21 November 2012

Nasty little pit

'Poor quality castings' is a criticism often leveled at Square Four Mk1s. Here's a nice little pit in the primary case. I might fill it, but it is not going to hurt anyone.


Monday, 5 November 2012

DIY Respite

So, a day came when there was no decorating or other householdy tasks, when the weather was not too wet, and there were no pressing domestic engagements. Amelia was mobile on her own (hitherto flat) tyres and we were able to face up to the beast that calls itself chain alignment.

My plan was to fully assemble the engine plates, gearbox and primary drive and determine once and for all whether I was going to have to modify, or replace the G107 gearbox.

The first job was to finally bolt up the engine plates with the correct studs - luckily I had enough of these and all of the special ones from the boxes of bits, plus the lower gearbox bolt from Acme Stainless. This was very straightforward, only needing a small amount of help from a jack to get the bottom front engine stud in and tie the bottom frame tubes to the down tube. All nuts on, and I was pleased to see the top & bottom gearbox lugs aligning perfectly within the plates.

Small problem - the bottom gearbox bold threads in the frame lug are caked in rust - must buy a 1/2" CEI tap to clear these. Previously when I had trial fitted the primary case I had realised that neither the special brake lever stop nor the side stand bolt would screw fully home, so I took the opportunity to clean the threads on those out - 5/16" CEI. Investment in tools pays of pretty quickly.

Here's the side stand trial fitted, to check it's function and to start to establish what spacer we need behind the inner primary case. Is the way that spring bears on the primary case as the designer intended, I wonder?
However, with the gearbox fitted we could take a look at the secondary chain alignment.  I wanted to use a toolmakers clamp to set a straight bar against the face of the  sprocket, and point it at the rear wheel sprocket. So I cleaned up the face of the sprocket in preparation. Of course, anyone who has  tried this will know there is no space to get a clamp in there!
So, it had to be hand held against the sprocket, which was a bit of a challenge when taking the picture! With the straight edge held against the gearbox sprocket, and the rear wheel roughly aligned, we appear to have a match. There is a small burr on the end of the straight edge, where it approaches the rear wheel sprocket which tends to confuse the eye a little but the exercise shows us that we have good alignment there.

So, onto the next task - building up the primary drive and the clutch.

This is pretty straightforward, since we have done it before - but never with the gearbox & engine fully bolted in!

The first small surprise was that when I had the inner primary case in, I fitted the top screw (the visible one) from the outside. I then found more screws (I don't have the original ones) for the lower positions and was confused when I found no thread - thinking I was in for a helicoiling session, I looked further and on the basis that both sides of these lugs are milled flat it looks like the lower three use hex bolts and nuts.

However, since the neither the Ariel parts book nor Drags list identify nuts for these maybe I'm wrong? But then, the Ariel list doesn't identify nuts for the engine plates either, so maybe it is a policy.

Any how, pressing on, we could then bolt up the inner case and re-fix the brake pedal stop at the bottom.











Next came the clutch race and it's thrust washers, which entailed making a special scraper to clear the gunge out of the clutch centre splines.

That all went fine.

Whilst I have new rollers for this bearing, there is no point in fitting them now - I will only risk losing them when I strip it again.










Getting around to fitting the clutch centre, here we can see the clutch sprocket has been fitted over the needle roller bearing. The  final thrust washer is in place as well, showing where the clutch centre will fit. I'm happy to see that the sprocket, bearing and thrust washers all fit and that everything is lining up for the centre to fit perfectly.















And here is the clutch centre in place, with a new tab washer. For some reason the new centre nut doesn't want to fit, thought the old one is OK. that proves the mainshaft thread is good which is the MAIN THING!







The moment of truth. Here is the straight edge again, this time across the two primary drive sprockets. the folded card is in there to hold the straight edge in place for the photograph  but the big news is that the sprockets align perfectly.






Two pictures here show the clutch basket in place with & without the clutch cover. Everything is running smoothly & freely, no sign of any misalignment here, so I think we can pronounce this potential problem, originally discussed in the Gearbox Woes post,  null & void.

Why we have a G107 gearbox number remains a mystery. Error in the factory? Curious that it has a J51 date code, which is November 1951, several months after the bike was shipped. Replacement part? warranty item? accident damage?

We'll probably never know.

Tuesday, 30 October 2012

Wisdom of Years


A silly boy once restored a BSA Bantam and when he came to put on his nice new tyres he thought "those old inner tubes look OK, I'll put them back in". And every week he came to ride his motorcycle, the tyres were flat and he had to pump them up.

The old inner tubes were made from some nice butyl rubber which like most rubber was natively good at passing small molecules through its elastomeric matrix. However as this rubber was very, very old and had become, over the years, very wise, it had learned how to pass the small gas molecules through its matrix very well and was now highly accomplished at the art. 

But, the time comes for us all and after a while the boy realised what he had done and decided it was time to retire the old rubber and he took the shiny new tyres off again, and replaced the 60 year old rubber, with nice new tubes. 

The new tubes still haven't learned how to leak, but the boy has learned not to scrimp on inner tubes!

But for now, dear Amelia sits in her shed with her old tyres and tubes which leak. Since I have no need to remove the tyres just yet, as I want to sort out lots of other things first, I have taken this handy can of tyre weld and re-inflated Amelia's tyres.

They are now full of fluffy goo. I'm told this is not good for tyres you want to keep, since once they are contaminated by the goo they cannot be repaired.

And so now dear Amelia can roll about on hard tyres and sit outside her shed in the sun. Here she is, ready for me to sort out her side stand, and her primary chaincase, and the gearbox.

Isn't she lovely.

Friday, 19 October 2012

How lucky am I..

Ebay can be a marvellous thing sometimes...

Do you know what I managed to buy? at a very reasonable price?

Yes! Its a cylinder head! It has all it's fins intact, it is clean as a new pin, it has new valves & guides, all the threads are helicoiled, both surfaces have been skimmed and there are no cracks!



There is a god... and he lives in Bungay.

Thanks again Draganfly!


Monday, 15 October 2012

Finishing the clutch

Easy job first - degrease and clean the clutch cover. Chrome plate as suspected, with a nice little ding at the front, presumable from someone's boot. Maybe we can beat that out with a handle planishing hammer and a sandbag... maybe not...
Clutch sprocket, plain and friction plates. All jolly nice; friction plates are worn but not burnt. Plate thickness is 1.6 mm/16 SWG, about 1/16". Cork protrudes anywhere between 1/32" & 1/16", so they will need relining. Since they are easily accessible from the outside, and i have 101 things to do, this job will get put aside for a dark winter night.

An additional plain plate, by the way, kindly provided by AOMCC member  & 'Cheval de Fer' magazine editor John Mitchell. Several other parts provided by John are stashed away to appear in later posts.

Next up, clutch basket, repainted by moi, cleaned original needle roller cage and thrust washer, and original pressure plate. John Budgen (John Budgen) provided a new set of rollers.
Here's the centre, which may need to be replaced. I've recut the threads, but as we've seen the splines are not good, inside or out. John Mitchell has provided another. Spring lengths vary 1.625 - 1.64", but since I'm not sure what the factory limits are we will have to see whether this is OK.

I nice set of new set screws for the basket to sprocket flange, with a tab washer - all from John Budgen.
Clutch, assembled and ready for testing. Clutch nuts all ok, spring cups ok, all assembled using my clutch screwdriver, pictured in an earlier post.

Friday, 12 October 2012

Clutching at straws

The clutch has resided at the bottom of the tea chest for almost a year. I think this is the only picture i have of it, sitting on the right of the shot in it's dome. Now I know what it is, it looks like an Ariel clutch though most of the special nuts are missing - but they were soon found in the box of miscellaneous fasteners.

However, since I need to finally face up to the horror that is contained in the gearbox i.e. the long search for a replacement case and mainshaft, I need to get to grips with the clutch and get it fitted.

So dragging it out, what do we have?

Here is the pressure plate, grubby but sound, with all its cups, springs and nuts. All ship-shape & Bristol fashion.

That mangled mess in the background is the clutch centre nut and the tab washer. That is for the bin.  
Here are the plates. One plain plate is missing; the others are mostly OK (no corks missing or horrendously worn) but will relining eventually. The cork protrudes above each plate in the range 1/32" - 1/16" - the plate thickness is about 1/16".
 Hmmm... clutch centre. Ugly.
Hmmm... clutch centre. More ugliness. The splines are very worn and I wonder whether we have a bearing or thrust washer problem that is allowing the centre to rub on the basket screw heads.
Basket/sprocket flange & thrust washers. No evidence of the centre rubbing here? Wierd. Bearing & thrust washers look ok, but most of the needle rollers are missing. Couple of screws missing too.
Here are the pressure plate slots in the basket - not much wear here.
And here is the sprocket. Again, looking good.











Now, we need:
  • tab washers
  • plates
  • needle rollers
  • maybe a new centre
  • a set of basket flange screws
Let see who's got what...