(And as you already know, click on the photos and they’ll open in a new window at full resolution, so that you can view them properly.)
You may recall that my now-sixteen-year-old, Jubilee-edition car was built for its mechanically incompetent first owner by Jim Bickley. At the time Jim was the development driver for both Westfield and Marcos and had his own race car preparation business. Mine was the fifth of five Elevens built for clients referred to him by the factory, at a time when they were not allowed to sell factory-built vehicles.
His were well built kits, using choice componentry. But, probably in an attempt to maximise profits and minimise build times, the donor vehicle’s components were swapped straight over, with only a lick of paint. Add in four years of spirited use by its wannabe-racing driver first owner, who was so mechanically illiterate that he took the car to the nearby MGOC workshops for servicing, and by the time that I bought it, twelve years or so ago, it was a bit of a heap.
Since then I’ve gone through EVERYTHING! Neither the original builder nor owner would really recognise it today. In fact, the only thing that hasn’t had major surgery on it is the gearbox. The Ford T9 unit was strong enough to be used in the Transit, so 430kg and 115bhp aren’t going to trouble it much.
But I’ll write it again: by his fifth build, Jim pretty-much knew what he was doing. Which makes the following slightly surprising……
I must have run the car for several thousand miles over a few years before the fan stopped working for the first time. I quickly diagnosed a failed radiator fan temperature switch. So I drained the coolant (I’ll come back to that momentarily), removed and identified the switch (a 79-88°C unit as fitted to certain Citroen, Peugeot and Talbot cars) and fitted a replacement. And all was good.
For a while…..
And then it failed again. I can’t quite remember when, but it might have been at the last Le Mans Classic in 2018. So I replaced the switch. Again.
And that was good for another few thousand miles. And then, arriving at Portsmouth docks a couple of weeks ago, outbound for this year’s Le Mans Classic, I noticed that the water temperature was off the scale. And it took all of thirty seconds to diagnose yet another failed fan temperature switch!
Although I actually had a new one in my travelling spares kit, rather than risk losing the coolant (and again, I’ll come back to that!) I disconnected the leads from the switch and bridged them with a spare 15A fuse. Therefore, for the duration of the trip, my fan was running constantly. It’s wired to the “hot battery buss”, which is always powered, regardless of ignition switch setting. So, to avoid draining the battery with the engine off, I simply killed the fan with the battery kill switch. This was a perfectly acceptable solution until we got home.
Back home last week and I set about changing the switch yet again!! As it’s reasonably high up in the coolant circuit, I wondered how little coolant I might lose if I attempted to swap switches without draining-down the system first. So I pre-prepared the new switch by wrapping the threads in PTFE tape, positioned a washing-up bowl under the car and, new switch at the ready, set about removing the failed one.
And lost not one drop of coolant! Turns out that with the cap tightly in place on the header tank, the air in the tank prevents the coolant in the reservoir from dropping. So the switch can be removed without any coolant loss. (Later, this turned out to be a “useful thing to know”!) I test-drove the vehicle afterwards and the fan worked as it should.
That was the only time that the car was driven between me fitting the switch last week and taking it for its MoT (for our few overseas members, the annual vehicle inspection) this week. The testing station is only half a mile from home, so I took it out for a couple of miles beforehand, to warm the engine thoroughly. And I’m delighted to report that it passed yet again with no advisories. Nigel, the tester who’s done all of my tests for years now, is a serious drag racer (formerly custodian of the 1949 Ford Pop “Detroit Spinner”, among other projects) and I ask him to be thorough every year. It’s the only check of my basic mechanic’s skills!
On the way home I went via the local Shell station for a tank-full of V-Power e95 (we’re off to Goodwood this weekend for the GRRC Member’s Breakfast Club, where the Eleven has been chosen to be one of the “GRRC Showcase” cars!!!). And it was there that I noticed the water temperature heading towards 212°F. Again.
Yes…… less than a week (and maybe 5 miles) since it was fitted, that bloody switch had failed.
And finally, the penny dropped!
Jim may have built five of them. And they might have been well appointed (albeit with corners cut behind the scenes!) But there was no relay in the fan circuit!!
As part of my own rebuild and upgrade program, I’d moved the fuse box and single relay (for the headlights) from under the scuttle to the left hand side of the instrument panel, behind the triangular panel. And both of those dash “wings” I’ve altered so that they’re each secured by a single knurled thumbscrew, screwing into a Rivnut in the frame. So accessing the fuses and relays take five seconds!
Putting an ammeter across the fusebox’s radiator fan position, I was able to read a maximum instantaneous current draw on startup of 13.5A and a steady draw, once running, of 5.5A. I don’t know what the switch can take, but it’s probably designed for much less than that. If I wasn’t to be replacing it ad infinitum, then I needed to add a relay to the fan circuit. But how?
I HATE exposed, visible wires. I’ve rebuilt my Tudor cottage and the only place where you’re able to actually see the sockets (and hence wires) is above the kitchen worktops. I even installed 2.5” diameter plastic ducting under the living room floor to take the AV cabling (speaker cables and video feed). The speaker cables exit the oak floor under the speakers themselves, and are never visible.
Same with the Eleven. Jim used the original Midget loom, and whilst it’s handy to have the correct colour coding, it was a bit of a dog’s breakfast. So, section by section over the years of my ownership, it’s all been unwrapped, joints soldered and covered in heat-shrink, and re-wrapped in proper (ie, non-adhesive) loom tape. But my fuse box and relay position is as far from the fan switch as it’s possible to get. To install a relay there would require the removal, unwrapping, re-wrapping and re installation of the ENTIRE loom!!!
Frankly, it would be less hassle to install a new switch each time that I drove the car!
The alternative would be to install the relay close to the switch itself. But I was absolutely NOT going to have flying leads and a generic relay hanging in space. Nothing screams “badly built kit car!” to me more than a rat’s nest of wires under the bonnet!
So I spent about seven hours after the MoT test, puzzling it out and installing my solution. I drew a wiring diagram, identifying the positive feed, switched feed and earths required, identified where those leads were in the vicinity of the fan switch and sought a suitable position to mount the relay. I wanted it to be accessible (to make replacement easy), yet as unobtrusive as possible. I also wanted it to be in a dry position in an engine bay that’s almost completely open to the elements and which I regularly clean with soapy water.
And I’m pretty pleased with my solution!
What’s more, there is absolutely NO sign that it’s fitted. And, whilst the fan still draws a peak of over 13A on startup and a continuous 5.5A when running, the switch only draws 1.5A.
Job done! (I hope!!!)