In order to get to this state I had to repair the damage to the right rear of the car caused by being attacked by an MR2 during the Birkett. There was actually rather more damage than I thought with the undertray being bent, the bodywork fixings having been broken and, worst of all, the right rear suspension upright being bent. Hence I’ve had to spent a lot of time taking that corner of the car to bits and straightening everything I could, and replacing various bits that I couldn’t repair.

I’ve also done loads of other bits: changed the engine oil, replaced a broken headlamp, re-aligned the suspension (which took ages), changed back to my proper race numbers, checked all the fluids including the diff oil and even checked the video and data logging systems.

However, I’m now ready to go. Mind you, I feel as if I’ve wasted the weekend when I could have been building the J15. Hence, I’ve promised myself that if I end up at the end of a race weekend with a Fury that’s going to take a lot of time to prep for the next race, then I’ll skip the race and concentrate on the J15 instead.

I have, though, done a few bits for the J15 since the last post. I’ve designed and made the fuel tank. As you can see, I’ve decided to make it out of cardboard instead of the normal aluminium. this way it’s a lot lighter which should help slightly.

Most entertaining though, was the first trip out for the J15. Because I needed to swap the cars around so as to get access to the Fury I took the J15 on a walk around the drive.  The photo on the right shows it’s back in the garage after a 47-point turn in the drive so as to swap it around with the Fury.

One intriguing things about having both the cars on the ground next door to each other is the obvious differences. The J15 is clearly going to be shorter in the body although the wheelbase is actually about 150mm longer than the Fury’s. It’s also apparent how short the J15 steering column, which is exposed in a very obvious way at the moment, compared to the Fury’s. This is due to the driver being nearer to the front in the mid-engined car; something that was always going to be the car but is made graphically obvious like this.

The biggest problem now is swapping the cars back over again. What’s more, I need those shiny wheels back as they’re one of my sets of Fury race wheels…

So, here’s a nice shiny picture of the final arrangement of the master cylinders, lurking at the bottom of the footwell.

There’s doesn’t seem to be much point actually putting any fluid in the brakes at the moment though, so I’ll leave that for a while. For all I know, I’ll find something that conflicts with one of the brake pipe runs at some point, meaning I’ve got to change the lines and I hate getting brake fluid on my hands.

As I was doing the hydraulics I ran the line to the rear for the clutch slave cylinder. I haven’t fitted the slave cylinder yet though. So, for the time being, I’ll just leave the line tie-wrapped up in position, as in the photo.

I still wasn’t too sure of the steering column positioning. I seem to have moved it around a lot and never been completely happy with it. However, this time I was determined to finish the job. Luckily, I think I’ve finally managed to do this. This time I’ve ended up using a completely (Escort) standard lower column and I’ve moved up the lower bearing mountings a bit more. This was getting a bit hard to do with spacers so I machined some bushes and welded them into a couple of bits of tubing that I welded to the chassis. (I know, I know…)

You can see all of these bits in the photo on the right. I really think that this is it for the column.

Mind you, there was one final thing to check in that I’ve moved up the column a bit more and there was always a chance that it was going to bash into the underside of the front bodywork. (Just what do you call the front bit of the bodywork on a mid-engined car? “Bonnet” seems wrong somehow. The rear bit is clearly the engine cover. Hmmm.)

So, I refitted the central tub and tried the front bodywork on for size again. The first problem was that front of the tub bashed in the fluid reservoirs as it was being lowered into position. This is because the roll cage requires that the rear part of the tub is put in position first and the whole thing “hinged” about the rear of the tub. Still, that wasn’t too big a deal with the help of a jigsaw. More dust in the garage though…

I said that I’d done all of the hydraulic parts of the braking, and that I have. However, that doesn’t mean that the handbrake is done yet. So, I then spent ages fitting the handbrake lever to the chassis, as in the photo on the right.

This might look a bit confusing as there’s a loop of cable. This is because the Wilwood calipers are a bit lacking in mechanical advantage for the handbrake so this arrangment gives a 2:1 mechanical advantage to the handbrake, at the cost of double the lever travel which means that you have to be a bit careful to adjust the cables so that there’s only a little slack in them. Experience from the Fury shows that that isn’t a problem though. As you might be able to tell from the photo, the cable comes out of the lever heading straight down. So, I machined a bit round lump of Delrin to run the cable around and bolted that in below the lever.

At the right side you can see the compensator that will be attached to the two cables to the rear brakes. I haven’t actually made those cables yet because I’m not completely sure how the cables will attach to the calipers. On the ones on the Fury I had to modify the levers on the calipers so that they didn’t bash into the inside of the wheels. However, I don’t know yet whether that’s going to happen on this car as I don’t yet have the wheels. I have ordered them though, Compomotive CXRs like the ones I’ve got on the Fury and as in the photo on the left. They haven’t arrived yet though. Until they do, I’ll hang fire on finishing the handbrake.

That’s all the J15 stuff. It may have escaped your notice, as you’re probably not as obsessive as I am, that the racing season is coming up full tilt on us. As it’s clear that the J15 isn’t going to be ready for the first race[s] of the season, I spent a while at the end of today just checking that the Fury still worked. I’ve got some more to do to it though before actually racing it. I wonder how you do it?

However, here’s a picture of a few alps as taken last week. The only problem is, I want to go skiing again; although I smashed myself up skiing a few years ago it’s still fantastic when it works right.

However, I’m back now and starting to think about it again. In fact, I’m also thinking about the new season and I think that next weekend I’m going to have to exhume the Fury and do some work on that in preparation for the upcoming first meeting of the season. I probably ought to do at least a bit of testing too.

Before doing that, though, I’ve been trying to press on with the J15. I think I’m in that part of a build where things appear to go slowly but, duck like, I’m paddling like mad behind the scenes.

Following Adrian’s principle of doing a system at a time, I’ve been trying to get the brake system all working. This involves a lot of pipework and much fiddling about with pipe flarers and the like. I’ve decided to use separate reservoirs for each hydraulic system this time and here they are, for the two brake circuits and the clutch.

Another change this time is that I’ve decided to use an electrical brake light switch, rather than a hydraulic one which seems to produce lots of silly little problems. You can see the switch just sticking onto the back of the pedal in this photo here. I bought the switch from Rally Design; it’s yet another of the long list of Escort Mk II parts that are still available.

As usual I’m trying to do most of the lines with hard Cunifer piping, as in the bit snaking around the front of the chassis here. This is tedious, but probably the right solution in the end due to the reduced flex in the lines when under pressure.

However, the master cylinders are rather tricky to get at, because of their positioning, and I’m probably going to have to make at least some of the lines flexible hoses from the master cylinders themselves as making hard lines there is just too tricky. Come to think of it, I’ll probably run the entire clutch line as a single flexible hose. Of course, in the process of doing all this pipework I’ve run out of just the vital fittings that I need; although I’ve got loads of fittings that I don’t need.

I’ve decided to relocate the steering column slightly and I’ve remade the lower steering column as a consequence. Although I might change  this again, if I’m honest. What I’ve done is to raise  the front of the column slightly to make sure that there’s a bit more clearance above my size 12s. The thought of a brake/steering/foot conflict at some moment is slightly worrying!

While looking at the pedals, I’ve been wondering about how to attach a throttle cable, which of course is going to have to be really long, to the throttle pedal which is shown here. Obviously, i could attach a cable by just drilling the lower part of the pedal and using a nipple over the end of the cable but I don’t really want to do that as it doesn’t allow me to change the pedal ratio at all. Ideally, I’d make something that would be able to move along the pedal a bit. Problem is, I can’t quite work out how to do it. Suggestions gratefully received…

First up was fitting the steering rack, which took about an hour. I’ve done this several times now and I still can’t work out how Jeremy managed to design this because it fits with fractions of a millimetre to spare.  There’s a trick to getting it in, and every time I fit it I work out what the trick is. And then, being a chap with ages neurons, I promptly forget again. Oh well, with luck this time it’s there for a good long time.

Then, as at the rear, I broke out all the carefully labelled acetal bearings and fitted all the front suspension and hooked it up to the steering rack. I haven’t fitted the anti roll bar yet, because I need to work out exactly how to make that yet.

What I do need to do, as you can probably tell, is to chop that aluminium floor panel up so that the wheels have something to poke through. I don’t actually have the correct wheels yet, but some of the Fury ones will do in the meantime. The offset is wrong, so the track will be rather larger than it ought to be, but if needed I can move the car around.

Everything was all going so well too. I assembled the left rear suspension, using all those bearings I made a while ago, and assembled the upright using the nice shiny new driveshaft.

Rats!

Bugger!

If you remember, a while ago I was concerned that the driveshaft was going to bash into the chassis. I had just about convinced myself that with the diff in the real location and the proper driveshafts, rather than the cut and shut ones, then it would be OK. However, that wasn’t the case, at least for half of the movement of the diff. The problem with the Riot/J15 chassis is that the space for the rear chain is quite limited (hence the longer chassis that I’ve got) and the shorter a chain run is then the hotter it runs. As such, I didn’t want to lose the rearward half of the diff adjustment. Clearly, the chassis was going to have to change but it wasn’t clear how.

I spent most of the night musing about it, and ended up doing what’s in this photo here. The photo’s of the right hand side of the chassis, as the photo was a bit better. Essentially, I’ve cut that diagonal tube in two and added in two additional support tubes, one along the side of the chassis and one to the rear bulkhead. Hopefully, that makes a sufficient number of triangles. As you can see there’s yet more POR-15 here, not applied particularly well because I was getting pretty cheesed off.

With all that done, of course it took a considerable amount of time, I could get back to re-assembling the rear suspension and transmission. This time it all went pretty well and in a while the whole rear end was assembled, bar a few nylocs and a missing bolt. If you look hard, you can see a long bit of thread sticking out of the upper right wishbone. This is a lump of studding I had lying around and is there in place of the bolt that ought to be there, but which seems to have gone walkabout in my hopelessly disorganised garage. I’ve probably put them somewhere safe. (The left hand side does have a bolt, as I managed to find and old M12 bolt of the right length but I couldn’t find another one.

Still, the tranmission and rear suspension is together now, barring a few bits and the still unmanufactured dampers.

Now I have to work out what to do next. I wonder what’s going to go wrong this time?

As you can see in the photo I’ve done what I said I’d do in the last post and added some tabs to which to bolt the diff support plates. Of course, that’s messed up the powder coating and I’ve had to resort to POR-15 to cover up the bare metal.

I’ve also added a couple of additional diagonals to the rear engine mount which you can also see in the photo. I’ve been thinking about doing this for a while now, after noticing when the mount came back from the powder coaters that the lower tube of the engine mounts was bent. At first I thought that this was due to the heat from the powder coating but as the mount still fitted the engine perfectly I’ve come to the conclusion that it was like this before, and is just much more noticeable due to the colour.

I’ve been drawing force vector diagrams in my head for some time working out whether I needed to add these tubes but as I had to mess up the coating anyway for the diff supports I thought I’d just as well do it anyway. At least that means I can stop fretting about it.

Just imagine what it’s like inside my head, if you can. All this worry is mixed up with tons of useless knowledge including the bit of set theory mentioned at the start of this post. The post, by the way, is the 100th of the new Wordpress era.

With all this done, I can hopefully get the diff mounted for a final time this coming weekend. That’ll be a relief. The problem is that the race season is approaching train-like at the moment. I just got my licence for the new year through and the first race is really only 6 weeks away, and I’m going away skiing for a week in there too. It’s increasingly clear that I have no chance getting the J15 ready for the start of the season and at some point I’m going to have to check the Fury over, which is been languishing at the side of the garage for ages now.

The plan is actually to make the seat backs easily removable, as are the tunnel side and tops, so that it’s easy to get access to the engine’s exhaust side and things like the oil filter.

On the subject of the engine, that was the next topic. So, I inserted some metalastic bushes in the mountings, where previously I’d use the turned adapters I showed you, and bolted the upper mountings to the engine. As a matter of interest the bosses in the CBR1000 block are tapped for M12×1.25 which is pretty hard to find as it’s something like M12 superfine. However, a quick search on eBay turned up a supplier to sells a lot of such things; very useful.

With the upper mounts on the engine I hoisted the engine up and located it in the top mountings, just letting it swing there. I then chocked up the engine (it’s easy enough to move around by hand) and bolted the rear mount to it. In fact, being a bike engine it’s always easy to move around. With the upper mounts on I picked it up and carried it across the garage. Given that that’s 180bhp and a 6-speed sequential gearbox I can never understand why other kit car builders use things like K-series and Zetec engines as they’re fantastically heavy in comparison.

Anyway, I could then bolt down the rear mount. This was a slight struggle as the powder coating seemed to have changed the shape of the mounting very slightly. Or, more likely, exposed some of the stresses in the shape due to the heat of welding it.

All the same, the engine was now in. Symbolically, I’ve threadlocked, or nyloced, all these mountings which is an indication of the fact that I’m intending this to be it. Until I realise that I’ve made some awful error, or course.

Next thing was to mount the diff. You will remember that I had a problem with the alignment of the split sprocket and took the diff carrier apart to see what I could work out. Using the other sprocket that I have bought I offered it up to the diff and it fit perfectly; meaning that it had been machined correctly. I then split that one too and, bizarrely, when I tried the parts of that on the diff it was clear that this one was exactly like the other. This is wierd, I can only think that the material has some energy built up inside it (not impossible as it’s heat-treated aluminium) and when it’s cut in two it changes arrangement very slightly. So, in a grasping at straws manner and in a manner encouraged by Adrian, I tried just easing the hole in the sprocket that fits over the registration dowel with a rat-tailed file. That worked well and I ended up with sprockets that fitted properly. All seems a bit fishy though, and of course one of the sprocket halves now has a bit of play in it, I’ll have to bolt it in really tight…

I bolted the diff carrier back together and fixed it in place on the engine mount. The design that I did the CAD for a while ago called for a 5mm spacer on either side of the top fixing; I had decided that using shims, or similar, would make sense to be able to align things properly. As it was after much time with a straight edge between the drive and driven sprockets I ended up with a 4.5mm spacer and a 5.5mm one. That’s pretty good, I reckon.

I shortened the old chain that I’d got from Andy for alignment purposes and put it all in position. Things certainly go round and round in a pleasant sort of roundy way. Mind you, the chain makes a sort of thunk, thunk, thunk noise as the links hit the teeth on the drive sprocket. I assume that that’s what bike chains do, although not without me taking various things to bits to make sure that nothing was hitting anything.

As well as getting the triangular side plates laser cut I also got some locating plates cut, with a curved slot for the lower corner of the triangles. However, at some point while making the various mounts I must have taken leave of my senses because I never finished off working out how, and to what, I was going to locate these. I shall have to do that now, annoying because it means that I’m going to have to do at least a little bit of welding to the chassis and engine mounts, messing up the powder coating in the process. Oh well, it was bound to happen sooner or later.

I shall probably do this next, so that I can deem the engine and transmission done.

I added another two of the little b*******s to the car today, the first being the “shoulder” panel in the photo. By the way, in the background you can see the Fury sitting there all unloved and neglected. However, I’m going to have to start re-invigorating it soon. I’m hoping to get the J15 to a rolling chassis versi0n fairly soon so as to facilitate that.

I also added the panel at the front of the passenger side of the car, as in the photo.

The next thing I want to do is to add the side panel along the passenger side of the central tunnel. As on the Fury, I want to attach this with rivnuts so as to facilitate access to this area of the car. It’s rather less important than on the Fury, as there isn’t a propshaft in there, but nonetheless it would seem daft to make the top panel the only access.

While thinking about this, it dawned on me that as the handbrake lever was attached to the outside of that chunky upright, just near where the handbrake lever is loitering, then it’d make sense to make this panel in two pieces, one for the front of the space and one for the rear. As I’m using the same rear calipers as on the Fury I’m going to have to do the same sort of thing to increase the mechanical advantage of the lever as I did there. (Essentially a pulley giving a 2:1 advantage.)

I’m also going to have to arrange for the cable from the lever to turn around a corner, due to the geometry of the lever. Looking at Jeremy’s photos, a detail of which is shown here, he seems to have done this with a block of some plastic, and I could probably use a lump of Delrin for the same job, as used for the suspension bearings.

Now I’ve got the footwell panel in place, I can see the space that Jeremy uses for the fuel tank, as shown here. I did some preliminary calculations a while ago and the volume here was suitable. I did wonder about mounting the tank further rearwards, at  the back of the passenger compartment, but this is probably the easiest place just at the moment.

Now I can see the space properly, I’ll measure up and draw out a tank. I can then get it made, as I’ve done before.

The only difference between this and the previous ones, is that I’ve made one of the spacers that hold the plates in the right position. Of the other two apices of the triangle, one will bolt to the rear engine mounting and the other will have another spacer, but one with a connection to one (or two, I haven’t decided yet) turnbuckles for getting tension in the chain.

Many thanks to everybody for their suggestions about the sprocket conundrum. The more I look at it, the more I think the sprocket was just not machined properly. Or, perhaps the diff wasn’t. Really, I should have tried the sprocket on the diff before splitting it, and I’ll try the other sprocket I have soon like that.

One thing though, is that I was talking to Andy about it yesterday at the 750 Motor Club awards do. He reckons that it wouldn’t actually have an effect and, oddly, I tried running a chain around the sprocket today and it seemed to run just fine. In fact I now understand all this even less!

By the way, with respect to the comments, you may notice that some people, like me, have a pretty little picture by their comments and other people have a rather bizarre symmetrical bitmap. If you’re commenting on this blog, and others, you might like to whizz off to the Gravatar site, where you can set up a “Globally Recognised Avatar”. That isn’t something to do with the ruler of the 3D blue cat people (I haven’t seen it, I’d rather poke my eyes out with a blunt stick) but a little picture that applies on lots of sites.

Anyway, I put the sprocket issue to one side and moved on. One aspect of this is that I picked up the driveshafts at the 750MC party. They’re the shiny ones here, next to my fabricated dummies. They’re made out of some special Swedish unobtanium steel and should work well.  Yes, I know the new ones look as if they’re shorter, but that’s just parallax.

Unfortunately, it was time to get back to the panelling. Oh joy. First thing was to turn the chassis upside down and put the floor panel on. The plan is to completely cover the front part of the chassis, back to the front of the engine compartment, with a single piece of aluminium. I don’t actually know yet how big I want to make this at the front, so currently it’s the full width of the aluminium sheet. I’m planning on a lot of attention to the aerodynamics on this car and just throwing away plan area without using it seems daft. So, I just rivetted on like this. As you can see, there’s a lot of rivets here, this just wouldn’t work without an air riveter.

With the chassis back the other way up, I got stuck into refitting all the panels I made a couple of weeks ago. Only this time they were rivetted and bonded in, not just held in with clekos. As you can see, I’ve also bolted in the pedal box, this time using nylocs.

Next thing to do is to make the panels for the other side of the car. Although all of the panels shown here are rivetted in, I’m planning on using rivnuts for some of the other panels, so as to facilitate better access. In particular, I want to do that for the seat backs as I’ll need to get access to the exhaust side of the engine.

Here’s another photo. The hole in the panel at the side of the pedal box is there so as to get access to the pedal box’s bearing shaft.

First, though, the forward bits. Most importantly, the chassis is now back home again. As you can see, I took the trailer off back up to Soham and collected it. To be honest it isn’t a fantastic job, but it’s good enough. It’s not quite the shade of grey that I was after either, but that’s no big deal. Mind you, I wonder if I want to make the roll cage a different colour from this? In which case, I wonder if it’s possible to paint on top of powder coating? Seems possible that it’s not.

In addition to the chassis itself, I got this big pile of suspension and engine mounting bits. The coaters were not as good as they said about keeping the coating out of the threads, and in one case they’ve got it in the threads and not on the housing around the threads. But, it’ll do. I’ll soon get along to fitting all these parts to the car.

In the meantime, I wanted to finish off the diff carrier. Last time, I said I was a bit concerned about getting the bearings on to the diff journals. After much discussion and thought, I decided to actually have a go at pulling a bearing onto one of the journals. So, using a long M10 stud righ through the middle of the diff and a little dolly I made on the lathe, I had a go. To my delight it pulled in without any great drama. I stopped after a few millimetres because I didn’t want to make getting it off too difficult, which is the state it’s in the photo. However, it was clear that this wasn’t going to be too big a problem.

So, I finished off the various bits for the diff carrier plates. Here’s the first of them here. This is the outer side of the plate and you can see the bearing in situ and the holes that allow access to the bolts that retain the sprocket on the diff.

That looked as though it was going to work so I took the plates apart and pulled the bearings onto the diff with the inner bearing carriers in place. I could then bolt the plates and the outer bearing carriers in over the top of the bearings and I ended up with the whole lot as one piece. As I started drawing this months and months ago, before I got the chassis from Jeremy, this is rather a relief.

At that point I went into a bit of a decline.

I thought I’d try fitting one of the sprockets I bought ages ago to this lot. The plan, if you’ve been paying attention, was to split these sprockets so that I could bolt them to  the diff without taking the whole lot apart. In fact, putting the complete diff carrier together was a deliberate experiment on my part to see if this whole process was going to work.

First, though, I needed to cut one of the sprockets in two. So, with a new blade in the hacksaw frame I did this carefully and then proceeded to bolt it to the diff.

And then I noticed this.

On one side of the diff the gap between the two halves of the sprocket is considerably larger than on the other side, as you can see in the two photos above. Clearly, this can’t happen, as the sprocket should be registered on the mounting points on the diff flange. There’s something screwy about this that I don’t understand at the moment. One possible problem is that the mounting  holes in the diff are specified at 27/64″ with a 14mm registration dowel in two of them. (I’m not making this up…) I’ve got an M10 screw (not even a bolt at the moment) in the 27/64″ holes. That means that there’s 0.7mm of a gap at the side of the bolt. All the same, I thought that the whole thing was put into registration by running up against the body of the diff itself. In fact, there seemed precious little slop when I put it together. The hole size is very strange though. The largest imperial size that’s going to go through it is 3/8″ which leaves even more clearance than the M10 one.

Hmm, I’ll need to think about this. What I’ve got at the moment is clearly unacceptable.