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And the rest...



MODS 3

So, mods Mk III started. The problem with the brakes was soon diagnosed. The symptoms were a bit odd - if you drove the car for a while, the brakes needed to be pumped up. However, if you pumped them up so they worked, and left it overnight, the pedal stayed firm. Unlikely to be air in the system, therefore. I assumed it was due to the pads being knocked back, and it turned out this was the case. The off road experience over the kerb had loosened the front wheel bearings and this was causing the pads to get knocked back. In fact, I think this was also the reason why the speedo was only working occasionally - I suspect that the wheel was wobbling so much that the magnet wasn't always passing over the sensor. Gulp! New wheel bearings for me, I suspect. In fact, I tightened up the bearings and they seem to run OK. Only time will tell, but I'm loath to change them if they're OK.

First job was to wire up the toggle switches on the dash, and add a 2-way ignition lock on the dash. The toggle switches work as follows - the first on the left switches on the ignition, in the same way as the lock does. The second switches the fuel pump, and the third switches the ECU power supply.

I then diagnosed the neutral light and water temperature gauge problems. The neutral light was on the whole time because while remounting the clutch slave cylinder I'd trapped the wire to the neutral switch between the engine block and one of the ali spacers holding the slave cylinder in place. This had shorted the wire to the engine block, meaning the neutral light was on the whole time. Easy to fix, however.

The water temperature gauge was dead because the sender had died. I'd taken it out to see if a CAI one, matching the gauge, would fit. According to my Blackbird service manual, it should've, but it didn't, so I replaced the original one. I assume I managed to damage it in the process, although I'm not sure how. It's definitely dead, however, as it has infinite resistance across between the contacts. I ended up retapping the hole for the sender to match the 3/8" NPT 24TPI thread on the sender. It's now fitting and the connector's changed for a spade connector.

Next was the fuel sender. There were two ways of doing this - either I had to remove the fuel tank completely or hack a hole in the GRP covering the fuel tank. Although the 'hack a hole' system would mean that I would have to make a covering plate up and 'bond' it into place later, which I didn't really want to do, taking the fuel tank out was a prospect worse than death so out came the hacksaw blade.

Cutting a hole out above the fuel sender was not as bad as I'd expected as the GRP is very thin. Getting the sender out was a bit of a faff but after a while it was all lying on the rear wing. Unfortunately, when getting out of the car to have a look at it, with all my usual elephantine grace, I managed to knock the fuel sender off the rear wing, stumble out of the car and tread on it. Fortunately, no lasting damage was done.

I didn't really bother to work out why the connections weren't working as there was clearly a short and I just replaced the wires to and from the sender. However, testing the fuel sender (with a multimeter) and the gauge (with a variable resistor) it became apparent that they talk different languages. The fuel sender goes from 180 to 10 ohms, empty to full. The gauge goes from 10 ohms empty to 180 ohms full. There were two alternatives: either try and modify the existing sender or buy a matching one from CAI and hope I could get it to fit. In the end I went for option 3 - sod it, and hope my brother's digi dash comes on line soon.

My excursion across the mud and gravel had thrown up a lot of crud into the engine bay and the rear of the car and this spurred me on towards panelling the underside of the car. I started by panelling under the transmission tunnel. When I cut out the floorpan sheets I laid the chassis on top of a sheet of ali and drew round the areas which needed to be panelled and then cut them out. This left me with an ali sheet the right size to go down the transmission tunnel. This is now held in place by 8 small ali angle brackets rivetted to the bottom chassis rails with rivnuts onto which the ali sheet is bolted. When I first put the ali sheet in place it was quickly apparent that the sheet was very flexible with only 8 mounting points, so I've rivetted lengths of ali angle onto the sides of the sheet to stiffen it up.

I also panelled the underside of the engine bay. A cut out is necessary for the sump and the gear linkage although I was rather conservative with my tolerances so there are large gaps between these items and the sheet. The panel is rivetted and bonded although I suspect it will have to be replaced when I add the extra chassis member to hang the electric reverse off. When I do this I can close up the gaps. The idea of course is not only to limit the incursion of road dirt into the car but also to smooth off the bottom of the car to reduce drag and (hopefully) generate a little downforce or at least limit lift.

Next, I wired up the toggle switches which I'd previously installed on the dash and added the dash-mounted ignition switch. The key switch controls all the power, as does the toggle switch next to it (redundancy, but hey!). The next toggle switches controls the fuel pump (I'd added an extra length of cable when I wired in the fuel pump and this switch merely disconnects the power wire) and the toggle on the right hand switches power to the ECU so that the engine can be turned over without firing. I also added a fuse to the ECU power supply as I'm not sure that it's fused otherwise.

While in wiring mode I also replaced the damaged neutral light wire and tidied up some of the wiring. Need some more blue vinyl tape though.... ;-)

I then fitted the new aeroscreen and the 'HUD' for the shift light and gear indicator. The HUD looks little bodged at the moment but it's only a prototype - I eventually plan to make a nice carbon housing for it. I was just about to wire in the gear indicator box when I realised there was a problem with the design - totally my fault rather than my brother's. I'd assumed that the neutral light was switched on the positive side and that when it came on there'd be a 12V source. However, it is of course switched on the neutral side so if we connected the gear indicator straight to the neutral light it would see 12V the whole time. Fortunately a minor mod to the circuit to make the neutral light a pull-up solves this. I haven't got round to modifying the gear indicator circuit yet but it doesn't look like too big a job. I also ordered a load of Molex Mini-Fit Jnr connectors from RS to connect up the gear indicator and the shift light (when it's finished).

I ended up having to chop the corner off the HUD to get it to fit under the aeroscreen. Unfortunately it soon became clear that the old aeroscreen and the new one are different shapes and that the new one is lower, hence the chop! Fortunately, the new aeroscreen doesn't seem to suffer from the same assymettry as the old one which was higher on the passenger side than the driver's side. One other difference is the colour - whereas the old one was a dark grey, the new one's a sort of bronze colour. The jury's out on this one, although I really don't want to have to change it again! I also had to chop out a section of the aeroscreen for the new centre mirror (from Racetech, cost about £28), as otherwise I'd have to look through part of the aeroscreen to see the mirror. I worked out where to make the cut-out using the old aeroscreen as a template.

TIP: When cutting the aeroscreen don't use a plastic jig-saw blade. The teeth are too fine and it just heats up the plastic, melts it, and it then welds itself back together again behine the jigsaw blade. Use a wood blade with nice chunky teeth instead. Again, I used the old aeroscreen to test the jigsaw blade before hacking the new one apart.

The aeroscreen's bolted down with the M6 bolts which Fisher used when they re-mounted it but some of the bolts have been replaced with M4 stainless bolt heads using pop-stud fittings as washers. This is for the tonneau cover which is going to go right over the rollbar and the aeroscreen, an idea suggested by Mark Fisher. Unfortunately it took Namrick over a month to get me the M4 bolts so this took rather longer than it should have done.....

I've been thinking about adding some extra stiffness in the chassis, taking advantage of the diminutive size of the Blackbird engine. One possibility which I've seen on a few cars, including Gordon Griffin's, is a sort of strut brace linking the two sides of the front suspension. However, it became clear that with the oil cooler in its second location it would be in the way. So, the oil cooler moved again (!) so that it's parallel with the radiator and much further forward. Hopefully this will provide enough space behind it to add the strut brace. It also looks much neater this way I think.

Having been rear-ended in Cambridge convinced me more than ever that an all-black car, while undeniably stylish, wasn't really sensible given the size of the thing. I'd already got some white roundels for the sides from Europa and some lengths of 4" wide white vinyl to use to make Cobra-esque stripes (I wanted silver but Zena, ahem, expressed profound scepticism as to the aesthetic desirability of this plan). Fitting the roundels was fairly straightforward although having to cut them where the main tub meets the sills tends to expose the rather wonky panel gaps :-( Fitting the stripes was altogether harder. In fact, it was originally a nightmare until I got the technique right. First of all there's the usual problem that the Fury's lovely curves make it very difficult to judge where the centre line of the car is since there's no convenient right angle to take a measurement off.

However, the Fury's body is hardly symmetrical so I ended up deciding where the centre line was mainly by eye. I then tried to fit the first stripe. I remembered then when fitting vinyl graphics it's a good idea to put some water on the surface so that the vinyl can slide into the right position. Then when the water dries the vinyl sticks in place. The problem is that the water just slides off the surface of the bonnet. Eventually after much f-ing and blinding I got the technique sussed. The trick is to get a piece of kitchen roll, wet it, and then add a little washing up liquid onto the paper. Then use this to smear a thin layer of washing-up liquid and water over the area where the vinyl's going to go (unfortunately thereby removing the carefully marked centre line!). Lay the vinyl on this film, and work along its length slowly with a piece of plastic like you get with pre-mixed filler (a little squeegy). To get the vinyl to stick and to help it round complex curves, heat it with a hairdryer as you press it down. It takes a while to get the technique sorted but once you do it all happens fairly quickly. The stripes are now on and look pretty good although I'm not sure that the stripes on the rear tub are in line with those on the bonnet! Still, it'll do for now....

Ever since the car's been finished it's had a slight but persistent oil leak from the bottom of the engine. One theory was that the replacement breather on the cam cover which I had to make to get the engine under the bonnet was too small, with the result that the crankcase pressure was blowing oil past the seals. That may still be the case, and I'm planning to make the breather much larger in any event. However, another possibility is that the leak is due to the sump bolt which I managed to shear when installing the chopped sump. The theory is that the oil is getting into the hole for the bolt and because the head of the bolt isn't there it's just falling out. This seems to be consistent with the location of the oil slick on the floor. Removing the sheared bolt was a job I was dreading but in the end it was far too easy! I got some stud/bolt extractors from Screwfix for only a few quid and using the smallest of these the broken bolt came out very easily. I drilled a 3mm hole into the bolt, and then used the extractor to pull it out. The extrator is like a taper tap with a left hand thread, so as you screw it into the broken bolt, it removes the bolt. Top kit, thoroughly recommended if you're allergic to torque wrenches like me.

I've now cleaned up the remains of the oil slick, so we'll have to see if this cures the dribbling.

TIP: The Screwfix extractors, for some bizarre reason, have a square drive on the end - the only downside to them as far as I'm concerned. I couldn't find anything to use to turn the smallest size extractor until I tried a 15 gauge spoke key for bike wheels. This fits perfectly and fortunately my Alien multi-tool which doubles as my garage allen keys, has one built in.

Now, the job which took longer than I had ever possibily thought it would - the new clutch set-up. There were two things I wanted to change. First, the clutch doesn't have enough travel. It's fine once you've got going, but it's tricky pulling away from a standing start. Secondly, I had to change the slave cylinder to the upside down position to get it to clear the propshaft but this required bending both the mounting studs and the pushroad, neither of which seemed like a good idea so I used my new pillar drill attachment (thank you Zena!) to make an adaptor plate. This is dealt with in the clutch section (see below).

In order to make the clutch pedal travel longer there are two options - either change the mechanical leverage or the hydraulic leverage. Keeping the Honda slave cylinder meant that the hydraulic leverage could only be altered by changing the MC bore. The MC is already a rather rare .5 inch size and I haven't been able to find anything smaller. So that's out, leaving the only option of changing the mechanical leverage. This looked simple enough. The original clutch pedal is an adapted cable operated clutch pedal, with the pivot about a third of the way up and the connection to the clevis on the MC being very nearly at the top of the pedal. This explains the lack of travel - there's virtually no mechanical leverage built into the pedal. I sketched a new clutch pedal, designed to pivot at the bottom like the brake pedal, with the attachment for the clevis pin on the MC being about a third of the way up the pedal. I sent the sketch to Mark Fisher who made up a new pedal very promptly and at a good price - cheers Mark.

Fitting the new pedal was another nightmare. First of all I couldn't get the pedal box out because the nuts were beneath the chassis and were now covered by my nice shiny panelling under the engine bay. I could just cut this open but I didn't want to, so I ended up taking the clutch and brake pedals out and leaving the pedal box in place. However, this involved cutting the end of the bolt holding the clutch pedal in place with an angle grinder waving around in the footwell. Not one for people of a nervous disposition....

The next problem was cutting a hole for the new MC position. I was worried that with the way the footwell slopes in at the bottom there wouldn't be enough room and that the side of the MC would protrude out of the side of the footwell. It turned out that this wasn't a problem. The second difficulty was that I didn't have a hole saw of the right size, so I ended up stitch-drilling the hole and filing it out. Not a nice job since I had to drill from within the footwell....

Once the pedal was installed and everything returned to its rightful home, another problem was quickly apparent - in the original installation the clutch pedal at rest wasn't upright but leant forwards slightly. With the pivot point being moved much lower down, this meant that the angle of the clutch pedal changed, pushing the pedal towards the driver. The clutch pedal was now about an inch and half in front of the brake pedal - not ideal and a recipe for a sore left leg on long drives unless you ride the clutch.

Again, there seemed to be two options - move the pivot point on the pedal or make a spacer plate for the MC. I didn't like the idea of the spacer plate as it's just adding unnecessary weight. At this point, the sky opened and inspiration struck. The clutch pedal lever has 16mm holes drilled up its length to save weight. The clevis pin bolt is M8. Therefore, if I could insert a ball-race with a 16mm outside diameter and an 8mm internal diameter in one of these holes, then the clevis pin bolt could go through this! This would move the pivot point back by around 3/4 of an inch - perfect. I ordered a suitable ball race from Gerald Summers along with some other ballraces for my new gearlever (more to follow on that one). I had to 'relieve' the clevis with the angle grinder to get enough clearance but once that had been done it all seems to be OK! Not tested yet though...

There is of course a third option which is to chop down the MC pushrod and tap the thread further along it to move the clevis further back. I wussed out on this one although it's actually probably the easiest option! Basically, I wasn't sure what the correct thread would be for the clevis.

More to follow.....



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Material Copyright © 1998 Dan Bromilow