FH - hooking up the oil tank

 There's a few jobs knocking around at the moment and it's all starting to get a bit confusing. This next task is aimed at preparing for running the engine up on a power drill to circulate the oil before we put it under any load. 

First off I'll have a look around the oil tank and make sure it's clean and to make sure that I understand the connections - basically that so I don't make a mistake when I'm hooking it up.

Looking inside the filler neck with a camera reveals the return pipe and its hole just above the return strainer.

Next to this on a flat ledge is the restricted hole which leads down to the chain oiler:

Deeper in the tank we can see the feed pipe which is raised above the bottom of the tank, and behind it the drain plug which unsurprisingly is right at the bottom of the tank.

The next step is to finalise the hooking up of the oil lines. These are connected correctly, with the feed pipe on the outside of the tank going to the feed connection at the bottom of the engine.

Next we'll swill out the tank with paraffin, finalise the screwed connections, and make up the push fit hoses for the chain oiler and the rocker box oil feed.

FH - centre stand

 I noticed as I was building the Huntmaster up that the rear wheel was in contact with the deck of the lift. Now I did specify rear suspension units that were marginally longer than normal to give me some extra travel and some extra comfort but I hadn't bargained for the fact that the centre stand had so little lift that the wheel touched the ground.

Shame I painted it before I noticed this, but that's the way it goes sometimes. I found a spare moment and removed the springs again using 2.5 mm copper wire wound into the open coils mainly because I didn't have enough thin washers to hold the coils extended. The springs came off relatively easily and I built up the stand stops which were rather worn, using the TIG welder. This picture shows one of the stops part way through the process: I added another layer because this did not prove to be thick enough.

Testing installation for the second time gave me 3/8" of clearance to the rear tyre. The lift has a removable panel under the rear wheel to allow the wheel to drop out and this is something like an 1/8" thick, so we probably have a total of 1/2" or so of lift off the ground. 

That job was a lot easier than I thought it might be. I had the welder set to 60 amps with quite a long stick out to allow me to get into the corners of the stand stops. I didn't have worried about the paint - it was scarcely burnt. 

Whilst I was under there I fitted the spacer between the frame and the primary case. Now all Ariels need this spacer and it is of somewhat variable thickness. Unfortunately I realised that I should have fitted the spacer before the primary case went on; withdrawing the gearbox bottom bolt at this point to fit the spacer would have released the centre stand springs that I had worked so hard to install.

This photograph therefore is here as a reminder to me to fit the spacer properly next time I take the primary case off. Right now the spacer is of a C-section so that it can be fitted without withdrawing the bolt.

FH - gearbox

 First off let me just say that I'm not going to rebuild the GB gearbox on the Huntmaster just yet. The gears select well, there's no play in the mainshaft, no lateral play in the gearbox as far as I can tell and whilst there's a little bit of movement in the sleeve gear it's no worse than other gearboxes I've looked at at the outset. Turning the shaft by hand doesn't reveal any strange noises so I think we'll just leave it be for the moment. 

However, there is something strange going on. When I assembled the clutch I discovered that I couldn't get the plates to touch, even when the screws were done up relatively tightly against the springs which made me think that perhaps there were two ball bearings within the main shaft. I fitted a new one when I replaced the push rod but now that the pushrod assembly is effectively over long I think there may be two. 

Of course I can't remove the ball bearings from the clutch side because they are right down at the other end of the mainshaft and I've no means of pulling them out. Therefore I've got to remove the kickstart case cover, have a look at the clutch mechanism and remove the balls from that end. This will give me a chance to polish the kickstart case cover to match the timing cover. Secondly it will give me a chance to look at the mainshaft end float and to learn a little bit about the gear selector mechanism on the GB, which I've never looked at before.

The kickstart quadrant is in lovely condition:

It looks very clean inside and it's immediately obvious that the design is a little more sophisticated than the BA/CP type that I'm used to. The mainshaft has no detectable end float that I can find. It's obvious that the gearbox has only had oil in it; though I will probably use the Morris K400EP grease in it as usual.

Moving the pushrod from the clutch side, having pulled the lifting mushroom out revealed something rather strange. There's a large lump of what appears to be oily rust sitting at the end of the main shaft:

I pushed this out and then ran a little roll of paper up and down the inside of the mainshaft swabbing out the remaining muck. It was at this point that I realised that the quarter inch push rod that I had made in a previous post is the wrong diameter for the GB gearbox. Speaking to the various members of the club, including the gearbox specialist, revealed that GB gearboxes use a 5/16" diameter push rod. 

While waiting for some new bits to arrive I'll polish the end cover:

FH - clutch

 We left the Huntmaster earlier this week with the clutch basket fitted loosely. After a busy few days doing other stuff I had a few moments this afternoon to progress the clutch.

The clutch basket tab washer is quite difficult to access. All the post war Ariel clutches use this washer so I've fitted a few of them by now. What you have to do is to bend the edges up in the vice before you fit the washer to the clutch basket.

When you have fitted the washer and the screws and tightened them up to your satisfaction, you can use a thin chisel and a bit of round bar to tap the tab washer up against the flats of the screws.

With that bit done, you can move on to the clutch centre. I have bought a few clutch baskets new from the AOMCC gearbox spares specialist recently and they come disassembled. You have to fit the clutch springs studs to the clutch centre - I used red Loctite for this, and you can rivet the backside of the stud in place.

The next job will be to rivet the backside of the spring studs:

The routine here is to centre punch the stud, then form the river head with the ball pein of your hammer. In fact, that produced an over-long rivet head that fouled the clutch basket screws, so these studs had a little go on the linisher before the second attempt at forming a (shallower) head:

The vague dome shown above is fine. You can just about see the stud has mushroomed into the holes that the AOMCC thoughtfully countersunk (countersank?) for them.

Next step is the tab washer. These are supplied flat, but need a little crank to fit:

The clutch holding tool comes in handy here, allowing you to hold the basket and centre still while you heave on the clutch centre nut:

For the record, the tab washer is bent up to hold the nut from shaking loose:

That's almost it for the clutch; I assembled the plates, and realised that the pushrod protrudes too much which means either the adjustment is all wrong (I haven't touched it yet) or there are too many balls in the mainshaft. Either way, we need to go to the other side...

FH - primary case again

 Just a small update today. The primary case is now on and together; I fitted the outer cover with a gasket with Wellseal on the outside and grease on the inside. It took a while to identify all the screws (stainless steel from Acme), but it's finally together. 

The clutch basket is a trial fit for the moment - I haven't bent up the tab washer yet.

FH - clutch pushrod

 I usually make clutch pushrods for the simple reason that by the time I find that I need one I don't usually have the time to order one from one of the main suppliers. You can make them very easily with material from eBay or somewhere like that: they're just a 1/4" round silver steel bar cut to an appropriate length. Most Ariel ones are around 12 1/2" for the CP & BA boxes; later models with GB gearboxes are around 9 1/2" or so and are 5/16" diameter. Don't take these figures as gospel since there are a number of different variations in length due to different mainshaft lengths, different numbers of clutch plates, and the presence of friction material in the clutch basket in the last machines.

When you obtain the steel it will be in normal condition and will require the ends to be hardened. This is very simple - All you need to do to harden the steel is to heat the end to cherry red and quench it in water. 

First, before hardening you want to cut the rod to the right length. It's easy to find the right length, because the wonderful people at Draganfly provide a parts list which has the lengths recorded. If you're feeling guilty about using their information but not buying the parts rest assured that you'll be buying lots of bits from them at some point or other!

Start by marking and cutting the steel to the right length.

Next you'll want to square up the ends and smooth them off. You can use a file for this but I usually use my bench linisher with the mitre attachment set to 90°. With the end squared off I like to put a tiny bevel on the edges just to soften them.

Next step is to heat the ends and harden them. Some while ago I took one of the mini beer kegs and turned it into a small furnace with some ceramic blanket and fire cement. It makes heating this kind of thing very much more efficient, because it contains the heat from the torch. You use a lot less gas and the whole job heats up a lot more quickly.

Next you just plunge the end into a cold water bath, and turn around and do the other end; the middle part of the bar doesn't need to be hardened. You can clean off the oxide colours if you want to but it's not necessary. 

Pop your push rod into the main shaft and you're ready to build the clutch. 

By the way, these pictures show a 1/4" pushrod in a 5/16" hole. You live and learn!

FH - fitting the cylinder head

 Fitting the cylinder head didn't prove to be the routine operation that I had envisaged. I started with a coat of Wellseal on the top of the block and on the top of the gasket. Prior to this I had cleaned out the threads in the block with a new tap and cleaned the threads on the head bolts with a new die. Two of the head bolts were damaged and needed replacement.

Lowering the heavy head into place was the usual faff but eventually I got a couple of the bolts dropped in on the near side. I wanted to put the corresponding bolts in on the far side next but for some reason I couldn't get them to mate with the threats in the barrel. After a lot of messing about I pulled the head off again to have a look:

It's sometimes a challenge when you buy pattern parts - in this case you can see that the bolt pattern in the gasket is wrong and the holes don't line up. I decided, rather than to use the composite gasket in the kit, that I would anneal the original gasket and reuse it. This is very straightforward - it's just a question of heating the copper to cherry red and leaving it to cool followed by a clean up with some Scotchbrite pad.

After that, and a second coat of Wellseal, the head bolts all went in easily. Neither Ariel nor the BSA service sheets indicate a recommended torque for these bolts but they do show a pattern you have to follow when tightening them up:

All that went swimmingly, as expected, and we now have the head fitted. Of course fitting the head opens up whole new set of work faces including the carburettor, the rocker box and the exhaust pipes. OK, the exhausts will have to wait until I have finished the primary case and I'm going to repair the stops on the centre stand as well since access will be better without the pipes in place.

More later.

FH - primary case

 I've bought (from Simply Bearings) and fitted a new spring link to the primary chain, tensioned it, bolted the gearbox up tight and finished the crankshaft shock absorber.

I spragged the sprockets like this:

There's definitely a split pin in the crankshaft shock absorber nut!

FH - dual seat

 After a lot of welding and modifications to the seat base to accommodate threaded fasteners, all previously shown in the blog, it's time to finish the seat. 

The first job, and this is part of painting activity, is to get the seat base coated with two-pack:

With the seat base on the bench we put some strips of double-sided tape on top of base. This is going to retain the rubber and stop it sliding about as we try to fit the cover.

This is the original foam rubber:

This is probably not the original cover, because it's PVC and not Rexine. I might be wrong of course because I don't really know when the industry stopped using Rexine for seat covers; all I can say is that my 1960s cars always had Rexine covers and not this very compliant PVC material.

The key thing with these covers is to make sure that the orientation of the seams line up with the appropriate parts of the base. Once this is done, it's sensible to retain them with as many clamps as possible. I've got a lot of these little spring clamps, which are very cheap, just for this job and a million others:

I've experimented with the different areas around the edge of the seat base to decide where I should start gluing. Some areas are much easier to access than others and some areas prevent access to other areas when folded over.

I'm using a contact adhesive from Screwfix which I use for laying lino. It seems to work very well and goes off in a couple of minutes. I've started at the front of the base and held it all in place with three large clamps. When this has dried enough to be very sticky I move backwards down both sides of the seat simultaneously.

When the sides are done I move on to the back. This is the most difficult bit, but cutting darts into the cover enables the glue joints to sit down quite nicely. You tend to go around the cover pushing the fabric into place as the glue goes off. I used a small hammer to knock the retaining spikes back because actually the glue does a far better job than those little metal spikes which are never in the right place.

That's it, finished and ready to go back on the bike.

I think it looks great. Some people think the seat looks better in black, but the tan colour is very characteristic to Ariel and I like it.

FH - rebuilding the ATD

 The only job that's getting in the way of timing the engine is the rebuild of the automatic timing device or ATD. I've got a kit with excellent instructions from Priory Magnetos, and this will replace the fibre gear and the springs on the old original timing unit.

The first part of the job is to remove this collar which holds the whole unit together:

After various activities with old cars in the past I've got a number of different pullers and ball joint splitters and all sorts of things like that knocking about. This bearing puller make sure work of grabbing hold of the collar and pulling it off:

The collar allows you to release part of the ATD from the section that carries the fibre wheel. The next job is to use a 3/16 drill to remove the rivet heads that hold the ATD to the fibre wheel. The pillar drill makes sure work of this little job:

You can then knock the rivets out, and essentially the whole thing will fall apart. You might have to untangle the springs and the bob weights but that's as far as it goes. This the units now completely disassembled and it's had a little while in the cleaning tank to get rid of all the old oil.

The next job is to replace the fibre wheel with the new rivets that are supplied in the kit. Before I do that I have a good look at all the parts to make sure there is no damage. In fact the unit has been apart before because one of the stops that prevents the unit over advancing has actually been replaced by some thinner piece of material braised in place. It seems to be in about the right place and it functions so we'll leave it as is. The second problem is the back plate is a little bit bent for some reason but that strains out quite easily with a small hammer and some judiciously placed taps.

With all that straightened out, we can rebuild the ATD using some new rivets and a new fibre wheel from priory magnetos. This goes together quite easily and it's riveted up using the ball pein of my hammer.

With the rivets in, we can assemble the loose parts of the ATD using some new springs and some lubrication for the moving parts. Then we can put the unit in the vise and squeeze up to refit the collar.

That's it, done for now until we're ready to time the engine.

Mini-Lathe - torque upgrade

 Inspired by Ted Hansen's book, I resolved to increase the torque available at the chuck using a smaller motor pulley.

Ted provides all the details of how to make a new pulley in his book. However I reasoned that if I could learn how to specify a timing belt pulley, which would entail learning how to specify timing belts, I would probably be able to find a ready-made pulley that I could buy. The target pulley: 12 teeth, 8 mm bore, 10 mm wide.

The standard pulley has 17 teeth; moving to a 12 tooth pulley should give us a 28% torque increase.

I discovered that timing belts typically come in a variety of forms centred around the shape of the teeth. The lathe uses a belt which has a trapezoidal form, and this is called an AT format belt. The pitch of the teeth is 5 mm which makes it an AT5 belt and it's quite easy to find an AT5 format pulley with a 10 mm width. The difficult bit is that the hub is typically quite small - the one I found had a 10 mm diameter hub which I needed to bore to 8 mm, which therefore has no room in the hub for a grub screw: the screw had to be drilled and fitted between the teeth of the pulley.

With the new pulley in place, I spent some time adjusting the level of the motor such that the belt would run in the middle of the pulley. From the dust on the end of the motor it appeared that the original pulley had allowed the belt to rub against one end and slowly abrade the belt.

With the adjustments I made the belt now runs in the centre of the new pulley which should lead to less wear. 

You can notice the change in motor speed versus the spindle speed now that the gearing has changed but you will have to wait for the next instalment to hear if this has made a difference to the depth of cut that I can successfully achieve.