As the super-duper dampers supposedly being built by my friend Dave have never appeared, as it was becoming increasingly apparently that there’s no point relying on something made out of vapour and wishes I finally decided to go elsewhere.

As I’ve had good experience of the Protech dampers in the past I decided to buy some of their new double adjustables. They arrived earlier this week and here’s one disporting itself languidly on the kitchen table. Of course, this means there will be 8 things to twiddle on the dampers which should confuse me alarmingly. The only problem I can see so far is that the twiddlers (and it’s black for bump, red for rebound) are really a bit close together and it could be rather tricky to adjust at the circuit.

The other super-duper thing was that I sent off the damper that I bent at Brands to Protech on Monday afternoon. Absolutely amazingly, when I got home yesterday it was back; this time complete with a rod that was straight. They don’t even appear to have asked me for any money which is odd. I’ll phone them to make sure I do pay them…

So, a big vote of thanks for Protech who, as before, get a prize for truly superior customer service. Fantastic stuff.

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?

Apart that is, from the really annoying problem that the taps I ordered turn out to be duff in that they cut, and then wrecked, the threads. So, that mounting block in the photo above has nadgered caliper mounting bolt threads in it. This means I’ve chucked away one set of taps, ordered some more from somewhere else and I’m going to have to generate a lot more aluminium swarf in order to make another mounting block. However, the whole process seems to work which is good. It’s just very annoying that I’m going to have to waste half a day hunched over the lathe.

I need to get the the chassis off to the powder coaters. I phoned them yesterday and they said they’d go a small problem in that their shot-blaster had had “relationship problems” over Christmas (! ) meaning that there was going to be a bit of a delay. That’s probably no problem as I’ve got lots to be doing. I’ll probably  try and take the chassis over at the back end of this week as I’m going to be dead busy next week anyway.

Next thing was to do the panelling over the top of the pedal box. However, I’m a bit unsure where the bonnet is going to be, so I put the pedals and steering column back on the car, and put the tub and, for the first time!, the bonnet on the car. It now looks like the photo here. (Except that the camera seems to get a bit confused about the colours.)

This means that I can now look underneath and have a look at how much clearance there is between the column and the underside of the bonnet, something that I’ve really  been guessing about up to now.

One of the reasons I bought the J15 is that I reckon it’s got a fairly small frontal area. That means the bonnet is low (and there’s no annoying induction lump in it).

As you can see, although the perspective is confusing, the suspension, positioned here at full droop, is pretty close to the bonnet, although there is about 30mm clearance so that’s OK. The steering column is well clear so there’s ample room to build an aluminium “tent” over the top of it.

After getting the chassis and other components ready to go to the powder coaters, that’s probably the next job. As you can tell, I’m putting off doing the rest of the really boring panelling.

At the right hand side of the previous photo, you can see the lower edge of the bonnet. Interestingly, there’s a substantial flat portion on the bottom of this bonnet. At first sight, this looks to be pretty much at the level of the bottom of the chassis. If so, that means I’ll be able to extend the undertray forwards so that the bonnet rests on it. I’m intending making it so that the bonnet just lifts off, rather than hinging things. As such, the undertray looks as though it’ll perform a couple of functions.

However, I’ve been waiting so long I decided to just work around the problem which I think I can. I certainly shan’t be putting any business their way in the future though.

Still, at least I could get going on this now. First thing was to fit the diagonal to the rear hoop and weld that to the chassis. So, I tacked things together and tacked the hoop to the chassis after cutting the bottom of the legs so that it would all end up vertical when it was fixed to the non-horizontal plates on the chassis. However, with it in position I realised that it could easily be too far forward in that there might not be room for a crash pad behind my helmet. So, I fixed a bit of hardboard to the hoop and checked how much clearance there was; in fact I videoed myself as it’s really quite difficult to work out how much clearance there is around your helmet when you’re wearing it!

That testing showed that the hoop was indeed too far forward and I had to move it back to the position that you can see in this photo. The problem with this, if you look at the bottom of the hoop, is that the legs are no longer above the chassis.

So, I had to extend the hard mounting points on the chassis which I did by welding in a chunk of box section in as shown in the photo, and then extending the plate I’d already welded to the top of the chassis.

With that done the hoop seemed to be fine, although the upcoming problem is working out how to attach the harnesses to the car. I’ve always known this was going to be an issue but I’ve never worked out what to do about it. There’s really two possibilities. One is to weld an additional horizontal harness bar into the cage over which the harnesses will loop before going to the chassis mounts. (This is what I did on the Fury when fitting the HANS device.) The second is also to weld an  additional tube into the cage, but to use that directly for attaching the harness to. Any suggestions gratefully received.

Anyway, with all that sorted I welded the diagonal properly into the hoop and welded the hoop to the chassis.

Then I had a nice cup of tea.

Next up was the backstays. As I’ve mentioned I wanted to make these removable. So, I turned some lumps of steel so that I could weld a pre-made insert into the end of the tubing into which I could mount a rod end. The joints I’m using are actually rather more expensive that the ones I normally use. They’re rated at about twice the maximum radial load that a normal cheapie joint is rated at. I decided I wanted to do this properly, you see.

I then welded some mounting to the cage and the end result is shown in the photo.

So, that meant that the back end of the roll cage was all done, and a view of the whole rear end is also shown.

I now had to fit the front hoop. First thing, though was to again check that there was sufficient clearance when I was wearing my helmet. So, I cut the base of the hoop at the correct angle for mounting it to the chassis (although I don’t yet have the hard points in the chassis) and held it in position with, errm, two G-cramps and a length of ½” tubing held in place with gaffer tape. Luckly, the tubing is CFS so it should be strong enough.

With that done I again videoed myself climbing in and checking this. You should think yourselves luckily that I’m not showing you any of this riveting video. The conclusion was that it seemed to be fine.

So, the next job is to put the hard points in the chassis and weld the front hoop in place. Then I need to do the roof bars.

The problem with all this is that the cage is horribly heavy. The regulations have changed and the whole thing is much heavier than the equivalent cage I have on the Fury. Oh well, I suppose there’s not much I can do about that…

Finally, the dampers have moved on a bit. I’m now being promised these at the end of January which will be OK for me; I’m getting more and more convinced that I’ll need to start the new season using the Fury, to be honest so it’s a good job that I haven’t sold it. To tease you a bit, though, here’s the latest rendering of the damper and reservoir!

As you can see, it fits in pretty well. In fact, the CAD model seems to have predicted how it will fit exactly which is nice to know. Also, with the diff at this position, and with the largest sprockets that I’ve got fitted, the chain seems to be clear of the diff mountings and the chain guard around the drive sprocket. Admittedly, it’s not far from the latter, but hopefully OK.

The main issue now is how to retain the bottom of the frame around the diff. There seem to be two ways of doing this. The first is shown in the CAD model and uses a couple of plates with  slots cut into them into which the bottom bolts on the triangular support plates fit. That will require two more laser/water cut plates though, and positioning the plates might be a bit tricky. Mind you, from what I can see of the current position of everything, a little bit of inaccuracy on this is probably no great problem.

The alternative is just to use a couple of turnbuckle like things, perhaps just lengths of studding really, to restrain the bottom corners of the triangles to the engine frame. In fact, I could even use turnbuckles that were arranged in a slight (plan form) triangle so as to locate the bottom of the diff laterally. That’s essentially what’s done on the Radical that I showed you the photograph of in the same post. It has the advantage of ease of manufacture and, perhaps, slightly easier adjustability.

While musing about this, I’ve pressed on with a few other things. You may remember that in an earlier post, I mentioned that the front lower damper mounts were really too low and wouldn’t allow enough droop in the front suspension. I did spend a while talking to Jeremy about this and he suggested that he could make some different front rockers. However, I thought I’d just do what I said and space the damper mounts up slightly which, as you can see from the photo, I’ve now done. This second set of holes is 30mm above the normal ones, which are themselves raised 25mm above the “standard” ones because of the lowered chassis on this car.

I’m now just about at the point where I’ve finished all the various bits of welding to be done to the chassis. The main thing left is the roll cage. The parts for this are currently  languishing in Fedex’s depot up the road in Huntingdon and I’m going to go and pick them up tomorrow. Or, perhaps I’ll just get them to deliver them while I’m actually in.

I’m planning on just welding the roll cage to the car directly, not bothing with making it removeable as I’ve done before. In order to do so it seems sensible to beef up the mounting points with some chunkier lumps of steel. So, I’ve started this off by welding some 3mm thick plates where the main roll hoop will mount. Also, you may remember that I’m planning on making the rear diagonal stays removeable so as to ease fitting of the bodywork. So, I’ve welded some attachments for the lower end of these stays to the rear of the chassis. The intension is to use a ½” rod end at each of the removeable stay so as to make fitting the stay straightforward. This at least means that the positioning of this attachment isn’t fantastically critical. This is something else, though, that will need a bit more welding when I can turn the chassis upside-down, hopefully in a week or so.

You can see these two hard-points, the ones on the left of the chassis, in this photo.

It’s time to fettle the Fury for the next race and I decided to do a few minor things including changing the brake pads. Unfortunately, while doing that I discovered another crack in the chassis around the front right corner. Here’s a photo. As you can see, it’s all a bit grubby after most of a season around here.

So, I spent a while welding this up. I then finished off by changing the oil and filter. Hopefully, the car’s now ready for Mallory. I do keep wondering whether I ought to beefing up the front corners of the Spectre chassis after all this.

Back in Spectre land, things are progressing painfully slowly, although hopefully competently. Along the way I’ve been planning a few things and one of them relates to the steering column. I’m planning on making this from the same 22mm OD seamless tubing as I used for the Fury’s column. On the Fury I used some standard ball bearings which work fine but they’re rather heavy. For the Spectre I’ve bought some plastic pillow block bearings from Igus as in the photo. These are fantastically light and, according to Igus at least, should be well able to work as I’d want. One thing I’ll have to do, though, is to make something that will locate the column axially. I’ll probably do this by making a couple of collars that go around the column, located by grub screws, and run next to the bearing.

Back on the Spectre chassis, I welded the crotch strap mounts on. At first, I managed to do this in the wrong place. That is, they were fine but I couldn’t actually screw the harness bolt in. Doooh…. So, with the careful ministrations of Mr Angle Grinder I cut them off again and welded some new ones in in a slightly better position, as in the photo here.

Next thing up was making sure that the ARBs were going to work. Having worked out what was what with the suspension I can see that I’m certainly going to need an ARB at both ends of the car. As such, the first thing was to check that the bars would articulate properly. It took me some time to make sure that the ones on the Fury worked properly and making the Spectre ones properly right from the beginning makes sense.

As  on the Fury, I made some ARB mounts  out of some aluminium blocks. I used the lathe, as in the photo, to drill a hole between two such block so that the blocks could clamp the bar in position. I’ve been holding ARBs this way ever since I first saw  it on the mounts I used for the front ARB on the Westfield  I built ages and ages ago.

I think this is actually the first time I’ve used the 4-jaw chuck on the lathe. As you can see with this you aren’t limited to holding a round thing concentrically, although it takes ages to set up as you’d like.

This is the rear ARB, or at least the Caterham bar that I bought while ago masquerading as such, in position on one of the mounts so constructed.

I then spent literally ages working out exactly how to articulate the bars  and the suspension. I’ve reluctantly come to the view that I won’t be able to use the Caterham bar as it is. However, making my own in the same style isn’t too much of a problem. What I will do is do it the same way, with a separate arm welded onto the bar itself, rather than trying to bend it accurately.

After much faffing about, I finally welded actuation tabs to the rear upper and front lower wishbones onto which to connect the bars. The photo here is of the rear version.

As you can see, the bar is connected to the wishbone by a little turnbuckle made out of a couple of rod-ends and an aluminium rod. I’ll probably  have to make a bunch of these, assuming that a female and male pair of rod-ends won’t be long enough. As you can see, this photo has a damper in there, which is really just holding the suspension at full droop. I’ve been measuring the chassis with respect to bump and droop and it’s all rather odd in that the front suspension is set up in such a manner as to really need a longer damper. That’d be a pain in the bump so I’ll space the front lower damper mountings upwards. However it seems very odd. I’ve discussed it with Jeremy and he’s at a bit of a loss to explain it. It should be easily fixed though.

While thinking about dampers, Dave’s sent me a picture of the Solidworks model of the damper reservoir, as in the drawing here. Neat, isn’t it? Dave was talking about putting dry-breaks in to the hoses to this reservoir but I think that’s probably overkill.

At the rear of the car, the problem is clearing the driveshaft. At the front the problem is the track rods. However, I also managed to find a way to make that work, as in the next photo. This photo makes it look as if the ARB actuation arm is impossibly close to the track rod. However, it isn’t actually that tight. Experimention shows that it should be fine.

Finally, for this update at least, I’ve started sorting the engine as I want to actually make the mountings. In order to do that I need to make it the right size so I’ve fitted the billet sump as in the photo here. I’d forgotten, though, that the standard sump bolts are too long. Hence, for now it’s attached with the standard bolts and some spacers, which are actually M8 nuts. However, I need a long term solution to that. Also while I was sorting the sump, I drilled and tapped it to 1/8NPTF for an oil temperature sender.

So, I tipped the Spectre chassis on its side-it’s still light enough to do that-and put the Fury in an accessible position and spent a merry 5 hours checking the suspension alignment, which all seemed to be fine. Hmm, that was a waste of time then.

In celebration I even washed the car, as above. What’s to bet that it pours with rain when we’re going to Snetterton and it gets all grimy before I even get on circuit?

Something else that happened at Silverstone was the the GPS receiver for the DL1 failed. This was rather surprising as it’s just a potted lump of electronics and as such you’d expect it to go on for ever, more or less. Luckly I had a spare one as I’d been concerned that something was wrong with the original one some years ago. So, I put the old one back in, this was in the assembly  area before qualifying, and it worked fine. I’ll have to hope that this one works now.

I have been wondering what to do about data logging in the Spectre. Most likely I’ll just transfer the DL1, or buy a new one. However, the quality of Race Technology products seems to have gone down recently, especially after the problems that several people have had with the display products. But then, I’m not sure what I’d do instead.

All the same, I checked the GPS receivers again in the garage and, sure enough, I did have a dead one (or perhaps one with a a dead cable). I’ll stick with the original one for a while.

Back in the land of the Mysterons, I have finally sorted out where I want to put the rear ARB, which is sort of at the top rear corner of the chassis. With that sorted I’ve welded some tabs to the chassis to which I’ll bolt some mounting blocks when I’m actually assembling the car. The only problem is that I hope I’m not putting something where I want the exhaust to go. I’ve also got to weld some actuating tabs to the upper rear wishbones. In fact, I need to do that for the front lower wishbones too, as well as making up the actuating arms. That should be pretty easy though.

One of the things that’s been concerning me slightly about the Spectre is the width of the cockpit for the driver’s capacious bum. Although he does fit tolerably well it could be a just bit wider; it is actually a bit narrower than the Fury one.

There’s a pretty obvious resolution to this in that the centre “tunnel” of the Spectre isn’t really there for any obvious reason other than for routing the coolant pipes down it. As such it could easily be quite a lot narrower. So, after much humming and harring I decided to do something about it. So, I cut off the bottom of those two tubes that you can see in the photo and yanked them using one of my favourite tools, a pair of luggage straps, forcibly in the direction of the passenger side of the car.

With that done by about 40mm or so, I welded a new plate to the floor of the “tunnel” and welded a new harness mount plate in. Luckily, I’ve got a collection of these, as supplied with harnesses over the years.

With that done it all seems pretty strong (in fact very strong). It’s not spectacularly pretty but it should do the job.

I’ve been continuing looking at what the roll-cage should look like and I’ve finally come up with what I thing I want to do. This is pretty much what I did for the Fury although this time I will weld the main parts of the cage into the chassis. If only because when it’s welded it’ll distort anyway which is a bit of pain when it comes to bolting it in.

I’m intending to make the backstays removable by the approach of welding a threaded bush into each end of the tube and attaching a clevis that will connect to a tab welded onto both the chassis and the cage. The Blue Book permits such things and there’s certainly plenty of cars around that do this sort of thing. The Blue Book is pretty unhelpful though; it says the bolts attaching the removeable strut have to be of “adequate strength”. (I’m not making this up…) Given that elsewhere they say things like a bolted in cage needs attached with 3 M8, 8.8 bolts this is bizarre. However, I did some calculations which say that a single 12mm 12.9 bolt has sufficient shear strength to decelerate an entire 500kg car at over 10g. As such, that should be fine as there should be rather more than one bolt doing such work anyway.

With all that done, I’ve given the dimensions to Jeremy who has a company who can supply the tubes, and bend the front hoop which is the tricky bit. He reckons he can get the tubing fairly soon and in the meantime I can get on with things like the engine mountings.

For example, I’m going to have to sort out what to do about a cage. Well, I could leave that but I’ve decided that making the cage boltable into the chassis is unnecessary and that I might as well weld it to the chassis. Hence, I’ve started work on working out what that should look like. One of the very initial CAD models of part of it is shown above. As when I did this before, it’s quite hard to work out what the cage is going to look like in the flesh.

There’s a problem with welding the cage in, though, which might well mean that I abandon it as an idea. This is that the central part of the bodywork, as shown here sitting laconically on the chassis, fits around the place that the cage rear hoop goes. That means that if that hoop is welded to the chassis, and there are two diagonal braces going back to the rear part of the chassis, then this bit of bodywork needs to become two bits of bodywork which is kind of a shame. However, I am going to have to modify the bodywork rather a lot anyway because I’ve got the long wheelbase chassis which means that the central tub (this bit) and the rear part of the bodywork are actually 60mm apart at the moment. So, I guess that might just be the way it is and perhaps I cut a portion of the rear tub off anyway. It’s a bit of a shame though.

I’m starting to look harder at the car’s suspension. As part of that I’ve measured lots of stuff and put all the numbers into SusProg, hence the picture at the right which is of the front suspension. This all says that the rear roll centre is 70mm above the ground and the front one is 10mm. TBH, it would be easy to change the pickups to change this but as it stands it sounds a reasonable start.

However, I clearly need to fit some anti-roll bars, much to Jeremy’s chagrin I guess. However, with the roll-centres at this high the roll-moments are going to be significant so the ARBs will be quite useful.

Hence, I’ve put the suspension on one side all together to get a better idea of where things are going to go, here’s a photo of the rear suspension, complete with driveshaft, and an ARB jauntily attached using some gaffer tape. Not sure that that’s the right place for the ARB though. In fact it might well conflict with the engine there so I’ll need to check this later.

Having decided that I’m going to powder coat the chassis, it means that I’m going to have to mock up a lot of things like this, and then take them to bit again. Oh well…

Similarly, the next photo of is the front corner all assembled together. In fact, while it was like this I took the opportunity to just eyeball the bump steer situation, especially because SusProg think the rack should be in a different position. However, it looks pretty good for now.

I’ve worked out where a front ARB can go, although I’ll need to make one because the Caterham one I bought doesn’t really fit very well. In preparation for fitting that I drilled a couple of holes in the chassis and welded crush tubes in so that I’ll be able to mount that easily later on. And, of course, the tubes can get nicely powder coated later on.

One of the reasons for taking the uprights apart was to change the wheel studs which really aren’t long enough for normal wheels. I really can’t imagine what sort of wheels they would be appropriate for. Before taking the studs out I tried the hubs against my existing wheels. For both of the sorts of wheels that I’ve got I only managed to get 10 turns of a wheel nut on before getting to the end of the travel. I know it’s not a cast-iron rule but the usual rule is that a wheel nut should go on by 1.5 stud diameters, which in this case of an M12x1.5 thread should mean 12 turns.

However, I had some longer studs, as in the photo and pressed out the old studs and inserted the new ones. One slight concern is that the design of the wheel hubs means that there isn’t really space to tie the backs of the studs together in the way I did on the Fury. I shall have to monitor that closely to check that the studs stay where they’re put.

With that done I put the uprights back together with my new brake discs and the Wilwood calipers. Everything seemed to fit nicely, although I haven’t put any pads in yet.

With that done it was back to the rear suspension. After all the faffing about with suspension bearings the last bit was to weld the spherical bearings into the rear lower wishbones. Essentially I did this by tacking one of the parts I made in position, and then assembly everything with some bits of cut-up feeler gauge clamped inside so as to make the correct spacing of 0.1mm in front of the circlip. Here’s a photo of what it looked like.

With everything tacked in place I could weld it properly. Mind you, this is one of the places where I could have done with a TIG set, and to be able to use it. The problem with MIG welding is that the heat input into the parts is huge leading to ample scope for distortion. Hence I took things very slowly, going off for several drinks as I didn’t want to end up with some useless lumps of steel blocking access to the wishbones. When everything was done, though, it seemed to work fine. Mind you, as I was starting to write this post I suddenly thought that I’d got the spherical bearings in the wrong way round, and that the braking loads would be taken by the circlips rather than the accelerative loads. However, after thinking it through 482 times I’ve decided I was wrong and they  are in the correct way round. Phew…

I now need to make some spacers to go between the spherical bearing and the upright, on one side, and the retaining nut on the other. However, that should be fairly easy for a man with a lathe.

After that I spent ages looking at how the pedal box fitted in the chassis. I think I’m going to modify the pedals slightly so that they don’t stick quite so far back in the car. That’s no big deal though. What I do need, though, is something firm at the bottom to mount the pedal box on as otherwise it’d only be bolted to the aluminium floor panel which isn’t very clever.  So, I welded in the plate shown here.

With that done I decided that any other chassis mods, and there will probably be a few, could easily be done with after the chassis had been painted. OK, I’ll end up having to repaint a few bits but that isn’t such a problem and it means I’ll be able to get on.

That meant I was going to have to tackle the horrible job of getting POR-15 all over me, the garage floor and the chassis. Still, it had to be done. Here’s the result of the first coat on the bottom of the chassis. After this I retired inside, somewhat fumigated, to rest for a while. With luck I can get on with the rest of this over the coming week.

Of course, there’s a race coming up, at Snetterton, as well and I’m going to have to do a bit of fettling to the Fury. I had been wondering if I could feasibly miss the last race of the season, at Mallory (!), in preparation for  the upcoming Birkett. However, having looked at the championship points position I really need to do moderately well in both remaining races.