Eureka!

Fuel enrichment

For a car to start from cold, you need a richer fuel-air mixture, modern cars use a computerised engine management system. Classic cars had a cable on the dashboard that pulled a lever on the carburettor(s) which allowed more fuel into the air stream. Guess which system is more reliable. Sometimes modern is not better.

Vintage cars are a bit light on engine management computers so a trusty cable system with a Bakelite knob mounted on the dashboard is in order. However, I really want to keep the instrument panel simple and elegant, a choke control is necessary but ugly. What else could I do instead?

Like a modern Grand-Prix car the Riley steering wheel has a bunch of control functions. Within a non-rotating central hub are controls for all the lights, the indicators, horn, distributor advance-retard and a hand throttle. All this is neatly wrapped in a Bakelite casting (unlike a modern Grand-Prix car). The existing hand throttle is connected via brass levers to the carburettor throttle linkage and is only used to increase the engine speed whilst it is cold. So that is part one of the enrichment solution inbuilt already.

The distributor advance-retard control is redundant because I have upgraded the ignition to modern distributor. So this gives me a control on the steering wheel that I could re-purpose. If you look at the picture below, the control in question is the metal item at 9 o’clock. The large teardrop ‘switch’ controls the indicators (non cancelling) and the control at 3 o’clock increments through side, dipped beam and full beam light selections. All of these controls connect to tubes inside the steering column and re-appear at the far end. You can just make out the hand throttle – its the black lever at 11 o’clock. That is actually mounted on the steering column just in front of the rev counter having been repositioned when I lowered the steering.

The challenge: the control on the steering wheel rotates (conceptually think left-right in an arc) but the fuel enrichment levers on the carburettors need to be pulled back, towards the driver. So how to convert a rotating left-right movement into a forward-backward movement. This took a fair amount of thought, because in addition I had to stay visually in period.

Below is a view of how the carburettor linkages are connected together and how they need to move – this is viewed from the side of the car

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I then had a Eureka moment fuelled by (sorry for the pun) an understanding of how Etype Jaguar throttle linkages change the direction of motion a number of times. A quick sketch later and I had a conceptual solution.

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If I inverted the rotating lever at the bottom of the steering wheel it would point outwards instead of inwards – so now when I move the steering lever the motion moves the relocated lever in an up down movement albeit in an arc. Converting an up-down movement  to a forward-back motion flipped at 90 degrees is easy if you understand lever principles and hopefully the drawing above explains it a little easier. There was a handy bolt on the steering box that just happens to be in a usable position. The ‘L’ shape lever needed to be fabricated from 2mm mild steel with the addition of a 20mm tubular spacer brazed on to the back to space the whole thing out from the steering box. All the parts were then connected together using spare throttle linkages and the result is this:

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Oh I almost forgot, Part of the challenge was to get the linkages to miss the immovable engine mount!

I am jolly pleased with the results of this weeks challenge 🙂 Maybe I should have made everything from brass? No that is perhaps a step too far…

 

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Instrument panel

After an awful lot of filing and shaping, cutting and drilling, the instrument panel is now taking shape. The position of the instruments is partly down to available space either on the actual panel or behind it. The positioning of the steering wheel and the intended priority of use.

The tachometer (rev counter) is more important than the speedometer so the speedo is smaller. Good job really because it is a perfect fit into the available space.

The other instruments are positioned so that the driver can see them 🙂

Also fitted is a battery cutoff switch (to meet race regulations) and a big Claxon button for the big Claxon ah-ooh-ga horn.

I am trying to keep the panel uncluttered but I imagine it will fill up over time as needs must.

The panel will be highly polished only once and then be allowed to mellow with age until it reaches a soft satin sheen.

Next steps are to build in reinforcing strips and a soft rolled lower edge to protect knees from abrasion.

I am quite please with the half way stage…

Aeroscreen glass

Well this evening was different and another step into the unknown…

The replacement glass for the Brooklands screens (actually called aeroscreens because they were fitted on WW1 aircraft) was of course new, the period 1930’s Brooklands frames are not new. Ipso-Facto naturally, the replacement glass doesn’t fit. It is very slightly too big for the original frames. Deep sigh of frustration – what to do?

I cleaned out the channels in the frames until they were spotless – but the glass still didn’t fit. Also, I discover that strangely one Brooklands frame is fractionally larger than the other. Strangely? Perhaps not, I have to remember they were made in the 1930’s when the quality mantra was probably “near enough is good enough”. Actually I should adopt that phrase at work, life would be far less stressful. But this doesn’t help me –  i need custom fitted glass.

I then had a thought – the people that created the replacement glass have ground the edges smooth. So if *they* can grind the edges smooth – then I can grind the edges back until the glass is smaller… This for me is a pretty scary idea, I dont even know if it is actually possible in a home garage. But when did that ever stop me?

My weapon of choice is of course my trusty angle grinder fitted with the most evil,  sanding disk I could lay my hands on. Spinning at 14,000rpm and with a light touch, I approached the glass with a degree of nervousness and gently brushed the leading edge  with the grinder… to my surprise, it *did* leave a sanding mark… so I continued gently stroking the glass with the evil grinder over quite a period of time until I had removed close to 3mm off one edge of the glass.

Below you can see the laminated glass held securely in a vice so that I could sand the offending edges. The ground areas are not visible so they dont need to be pretty.

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I then did the same on the horizontally opposed side. Although this was jolly boring (and noisy – sorry neighbors) the glass now slid about 75% of the way into the frame. Fast forward a few hours and I now have 2 fully fitted Brooklands aeroscreens.

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And in case you ask – yes the passenger aeroscreen *IS* supposed to be at an angle – If it was mounted horizontally true – the gap underneath would make it nigh on pointless. So nobody does that.

So far, i am properly pleased with how the car is progressing – our vintage sports car is beginning to emerge. IMG_3706

Poop Poop!

Exhaust Mounts

A short and sweet update – the exhaust system is now held on the specially made mounts with springs – in theory springs were used because it makes the systems quickly and easily removable, although I struggle to think why I would want to remove it regularly…

Below is the exhaust header mounting

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And here is the tail end mount. There is another one in the middle of the system that looks the sameIMG_3701

And the instrument panel is coming along too. You can see the four holes that produced the disks i used to make the wind deflector mounts. The picture below was taken before I fitted the Brooklands Windscreens.

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Wind deflector fabrication

The problem with having bespoke bodywork on your car is that a lot of parts available from retailers were not designed to fit the car which leaves you with a bit of a problem.  Take the two wind deflectors for instance (I can’t really call them windscreens). In period they come with a very simple 2 inch high mounting bracket on either end which whilst adjustable to a certain degree are not able to accomodate being mounted on anything other than a fairly flat panel. The bodywork on our car doesnt have *any* flat panels… The big butterfly nut allows you to adjust the angle of the glass so that in theory the wind is pushed up and over your head.

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I dont like these mounts and they dont fit my car anyway so what is needed is an elegant engineering solution.

I have spent many a happy hour across several months looking at how other people had crafted a way of bolting down the wind deflectors. Some had simply used the bracket shown above and lived with whatever angle the screens ended up at (in some cases it looked horrible) but most had come up with something else. Some people had removed both the bracket and the fixture it is clamped onto replacing them with a simple alluminium panel folded to conform to the shape of the bodywork. In some instances this looked quite nice but it wasnt really the look that I wanted.

Some people weld a vertical tube onto a spreader plate. The plate then being bolted to the bodywork with 3 or 4 bolts and the screen end is inserted and clamped into the top of the tube. This was more elegant but I didnt like seeing the mounting bolts and wanted something cleaner. Having learned to braze-weld alluminium recently, a design concept formed in my mind as I really wanted the whole structure to be crafted out of alluminium:

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Step one – investigate the challenge.

By far the most complex challenge is the highly shaped cowl in front of the driver, it has steep angles and complex curves. Having worked out where I think the best place for the screen will be – you can see below that the new screen vertical support needs to be cut at quite an angle in order to mount flush onto the curved panel

IMG_3682The round disk is a two inch ‘useful throw away’ from when i cut out all the holes on the intstrument panel – as luck would have it, I need 4 disks – 2 for each of the wind-deflectors and I had cut cut 4 holes.

You can see in the photo above that the disk needs to be slightly curved to match the profile of the bodywork and the bar needs to be cut at an angle somewhere around 45 degrees but its impossible to measure what that angle actually is. Rather than risk wasting lengths of alluminium – I cut a piece of wooden dowel (which is much cheaper) and sanded the angle until it fitted.

IMG_3683This particular support I then knew needs to be cut at 48 degrees. Before making that cut, using the lathe I drilled a deep hole into the end of the bar in readiness for fixing the threaded rod. This way when I cut the bar at 48 degrees – I would know for certain that the hole in the bar and the cut-off end piece would line up perfectly. In case you were wondering, the cut-off end piece would be used on the oppostite side of the body panel as it matches all the angles of the body work and allowing the nut to be fitted square to the threaded rod (see the sketch if my wordsd confuse)

A thread was then cut into the long bar and a length of studding fixed into place. Below you can see how all the pieces go together although for the photo I merely slid in a smaller bolt so you could see it as a unit.

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Transferring all the sections to the car means I now had this:

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The bar is purpously far too long to enable me to adjust the angle on the end until it  bolted in perfectly vertical. I needed the length so that a bubble level could be held against it. The bar was now cut to size and another hole drilled in the top to accept the screen fittment. Below is yet another trial fit and you can see where I am heading.

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The final stage was to braze-weld the disk to the bar so that they became one unit. The completed support will now be cleaned up and all the machining marks removed.

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I followed the same principle and fabricated the screen mount for the other side, the angles and lengths were all different but the process was the same.

And this is the finished result (before cleanup of the parts and fitting of rubber sealing washers etc). The broken glass will of course be replaced its only there for the photo.

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Now onto the passenger screen.

So much to do…

As much as I don’t want to rush the creation of our car, sometimes the enormity of the construction work is over whelming. Fabrication of components takes absolutely ages as does the making decisions on where things would be best placed for aesthetics and function. Of course there is also no manual advising on which parts to fit first so sometimes you can fabricate something then realise that once it is done, you cant fit it because something else has to be fitted first.

I had pretty much made my mind up that i was going to get the engine running in stages. I.e. connect the minimum amount of fuel and ignition components as possible to check they worked before expanding down the line. Fuel wise, the pump is fitted but not connected to the fuel tank, the pump can suck petrol out of a temporary can. The starter motor doesn’t need the battery to be in its final position, it can simply be connected via an old cable etc.  If when connecting the battery to the starter motor, it turns the engine over, then I will know that part works. If when connecting 12v to the petrol pump it pushes petrol to the carburetors, then I will know that part works. \

The problem is that life is not as easy as that – the temperature gauge that i fitted I now remember has to be inserted through the front of the instrument panel so I had to remove that and work out where the sensor tube will run through the engine bay, through both firewalls to the instrument panel. Skip on a few hours and that is mostly done – except I then remember that the instrument panel isn’t anywhere close to being finished yet so I can the gauge yet.

The oil pressure gauge likewise – work out where the copper capillary tube needs to go, fabricate a complex series of bends into it (get it wrong and start again) until likewise you realise that this gauge too is inserted through the front of the instrument panel. Skip on a few hours and the pipe work is now complete.

The Ignition coil needs to be kept cool so I want to keep that out of the hot engine bay and mount it behind the first firewall. Easy enough, except that the main high tension cable now has to go through, over or round that firewall. Skip on a few hours and the coil is fitted with suitable cutouts made and (forward thinking), some protective covering so the cable cant short out to earth on the bodywork. Fabricate the rest of the ignition leads. Skip on a few hours and this is now done.

Ah but if I fit the instrument panel, it is going to be really hard to mount the two tiny windscreens which need bolting down *behind* the instrument panel. Think about how to make the windscreen mounts. I think some 12mm aluminum rod, welded to a plate specifically contoured to match the bodywork and at the top weld it to a machined 25mm spacer with a 20mm hole through the middle that the main windscreen mounting bar can slide into. Yuh that should work. Problem, the machining I can do but i dont know how to weld aluminium. Skip on a few hours and I have taught myself aluminium brazing which it appears is plenty strong enough. Below is my first successful attempt at ‘brazing’ 12mm bar to some 3mm thick plate. This is just a test piece and it is unfinished. Once cool i put the bar piece in the vice and tried to hammer off the plate, it didnt move. I then tried to lever off the plate with some very large pliers and the 3mm plate bent. The joint was completely fine! Bingo. I can now fabricate aluminium components and add a new skill to the portfolio.

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Next onto the machining of the 25mm spacer which needs a 20mm hole through the middle. The lathe can drill up to a 10mm hole through the 27mm round bar, that means I have to machine out the inside of the hole until it is 20mm. I have never done this before and it took some time reading up and then getting the hang of ‘how’ to do that. Skip on several hours and I am still doing that… it is taking ages because you can only machine off a tiny amount at a time. Funny thing is I might not actually use the solution if it doesn’t look nice and I may change mind as I have another idea that would be easier.

We shall see… did I mention all this is time consuming? Fun though.

Instrument Panel

Being generally happy with the mockup version of the instrument panel I transferred the outline onto a sheet of 3mm thick aluminium. Not too surprisingly this is a lot harder to work into shape than the low density fibre board version plus it had to have an even gap around the edge so that at a later date I can place a thin piece of trim around the edge to match the interior of the car. 

Shaping the panel took a number of hours and I have no idea how many times I trial fitted it. Eventually I was happy and then worked out where the 5 brass mounting screws would be. I had planned ahead and the bodywork team had welded in thick tabs in perpetration for drilling and tapping. So all I had to do was drill a 3mm hole through the panel and the mounting tab to be sure the hole was in the same place on both parts. Next the tab on the car was drilled out to 4.25mm and tapped to take the 3BA brass bolts. The Instrument panel holes were drilled out to 6mm giving me about 1mm of clearance. 

The panel was bolted in with the protective film still in place. That will provide 2 functions: protection from damage whilst I drill sand and finish all the holes for the guages and the old switch etc, plus also it allows me to use it as a surface i can write in to mark out where all those switches and gauges will eventually be placed.

In the picture below you can see the new panel and the accurately placed guage images, the battery on-off switch and the klaxon button. I quite like the layout and think it should look quite nice once the aluminium has been semi polished. 

Next task is to cut all those holes out and a cutout for the steering column when it is raised back into position.