Nov 132014

Time pressures delayed the full electrical shakedown testing until after the engine was up and running. Power is only required to the ignition and fuel pump circuits to start the engine so all the other fuses were removed. Having said that, I did end up fitting the fuse for the instrument voltage regulator in order to obtain oil pressure and temperature readings while the engine was running.

The other fuses were now fitted in turn, stopping to test each of the components they fed, before moving on to the next fuse. The resulting snagging list was encouragingly minor:

  • The main beam can’t be flashed from the indicator stalk
  • The original hazard flashing unit is on the blink!
  • The brake fluid warning light isn’t coming on
  • The wiring to the rear brake and sidelights have been crossed over
  • One of the cooling fans is a little noisy and spins the wrong way!
  • The heater fan is making contact with the housing
  • Neither the washer or wipers work
  • Only one horn worked

Overall I was quite pleased with that for a first test. Especially as it was the first time the cooling fans and wiper motor had been tested since I rebuilt them and the washer, wiper, brake fluid warning light and horn were all simply missing earth connections. So easily solved.

Indicators and hazard lights
There was a fair amount of head scratching when wiring up the hazard warning light switch. The part number identified it as a hazard switch from an XJ6 and its pin connections conflicted with those in the Illustrated Parts Manual!

Hazard wiring diagram Hazard switch wiring

So I attempted to go back to first principles (or my understanding of them!) to work out the correct wiring. The one thing that was puzzling me was why separate indicator and hazard flasher units were used. They are essentially performing the same role – converting a constant DC supply into a square wave, with a suitable duty cycle to provide the correct flash duration and frequency.

The light bulb moment came when reading the requirements to pass an MOT. The hazard lights must be able to operate without a key in the ignition while the indicators are only powered when the ignition switch is on. The other difference is the power rating as the hazard unit needs to draw more current drive both sets of indicator lights at the same time.

The duty cycle of the unit is achieved by a bimetallic strip which expands and contracts depending on whether current is flowing. When the indicators are on, the current generates heat in the two metals, which expand at different rates. This causes the strip to move away from its contact and break the circuit. Without a current, the strip rapidly cools and the circuit is re-established allowing current to flow once more and the process to repeat.

Therefore the flashing frequency or ‘duty cycle’ is directly related to the rate of expansion/contraction of the bimetallic strip, which is a function of the current flowing. This is why modern LED indicator bulbs often do not work on classic cars as they draw far less current and therefore may not generate sufficient heat to switch the traditional units. Modern transistor based units are available to overcome the problem.

Therefore the switch needed to have the following connections:

Hazard switch in OFF position

  • Indicator flashing unit is introduced into the circuit (the two green wires are connected)
  • Hazard flashing unit is cut out of circuit (connections between the LGN, GR & GW wires are broken)
  • The indicators can then be operated via the switches built into the indicator stalk

Hazard switch in ON position

  • Indicator flashing unit is cut out of circuit (by removing power to its green wire)
  • Hazard flashing unit is introduced (by connecting its LGN output to both the GR & GW indicator feeds)

The only problem was the random frequency of the hazard flashing which was easily solved by fitting a new flasher unit.

Cooling Fans
The S2 cars have an otter switch to turn on the cooling fans at its rated temperature and requires a special connector, which has been on back order for ages. A spare dash switch was rigged up in its place so the fans could be switched on and off at will, which would be useful when testing and tuning the engine. The first fan spun up and ran smoothly and quietly, which was very pleasing, as they hadn’t been bench tested after their refurbishment.

However the operation of the second fan was noisier because the blade was not quite square on the armature shaft, causing vibrations. Removing it was a fiddly process with the engine bay completed so I was cursing not having bench tested it!

But more importantly, the motor was rotating the wrong way, pushing air forward towards the radiator rather than drawing air through it. Its effect would be worse than having no fan at all. When travelling at speed there would be a natural flow of air through the radiator. Having a fan blow against this flow would reduce the cooling ability.

It is rather odd because reversing the supply polarity of series wound DC motors (and indeed shunt wound motors) does not reverse the direction of rotation. The only way to rectify this would be to reverse the connections on either the field or the rotor windings (but not both!).

The rotating force (torque) on the armature shaft is the result of the interaction of the magnetic fields of the armature and the field winding – opposite poles attract, like poles repel. The directions of these magnetic fields are dependant on the direction of the current following through them.

Therefore changing the polarity of the power supply does not reverse the direction of rotation because both the field and armature currents will be reversed and therefore both magnetic fields. A double negative if you like, that cancels each other out!

The only practical option for these Lucas motors was to reverse the field winding, which was a very simple job.

Field wires just needed swapping All sorted – an easy soldering job

The fan now rotates in the correct direction to draw air rearward through the radiator. The fan was also re-seated to stop the fan vibrating so much.

I was trying to fathom an explanation as to why the motors were rotating the wrong way and then recalled that I had difficulty dismantling the two motors I’d acquired many moons ago, at the start of 2012. They were of the same design but had the fans mounted the wrong way round.

The person had indicated they were selling them as they had upgraded to modern fan units. However I suspect they had sourced motors from a different vehicle and noticed they were turning the wrong way. They had then mistakenly concluded mounting the fans the wrong way round would rectify the situation, rather than just improve their efficiency in making things worse!!

Wiper motor & Intermittent module

Intermittent control above
brake warning light

I’d decided to fit the Hella intermitted wiper module that other E-Type forum members had advocated. It works independently from the two speed wiper switch on the dash and the modification is reasonably discreet and reversible. The intermittent control uses the hole in the dash for the rear window heater on the FHC, which is blanked off on the OTS cars.

Like the hazard warning switch, the part number on the wiper motor switch also suggested it had originally come from an XJ6. The problem was the connected terminals were different to the correct switch (OFF 5-7, Normal 4-5, Fast 2-4) and so it was another case of trying to work out how it should be wired.

The combination of common sense and trial and error eventually produce the correct operation, which differed from the wiring suggested by the forum post. I’ve wired intermittent module into the ULG feed rather than the suggested YLG wire, which is for operating the motor at high speed.

At the same time, I also decided to add a jumper lead (with an inline diode) from the washer switch to the slow speed supply to the motor. Therefore the wipers now operate automatically while the washer switch is pressed. The diode is needed to stop it working in reverse, with the washer operating when the wipers are switched on!

Heater Motor
A complete new heater unit had to be fitted as the original had largely rusted away. The resistor, providing the dual speed operation, is riveted to the base plate of the heater motor. I’d foolishly assumed the new units would be supplied complete with the resistor already attached – dream on!

The resistor is sold separately and, due to the lack of clearance, requires the base plate to be removed from the motor in order to fix it. The wires are then soldered to the resistor rather than via spade connectors. As a result, the loom has bullet connectors built in, approx 6″ from the end of the wires, to allow the motor to be separated from the loom if it needs to be removed for servicing.

Resistor provides 2-speed operation Loom wires are soldered in place Fitting was tricky due to
the engine frame

However the looms didn’t come with the rather crucial two wires needed from the resistor to the motor terminals! The other issue came trying to re-fit the motor to the heater housing which had already been attached to the bulkhead. Removing it wouldn’t be an easy option as the cooling system had now been filled.

The reason the motor and fan cage couldn’t be fitted onto the housing was the base plate fouled on the engine frame. It was necessary to detach the fan cage from the motor by undoing the clamping grub screw. This allowed the cage to be fed up into the housing and then reconnected to the motor once the motor was clear of the engine frame.

The fan just had to be re-attached ever so slightly nearer the motor to cure the fouling problem found during the initial shakedown tests.

Alternator testing
The electrical component that I’d been putting off testing was the re-wired alternator. The modifications to the alternator were more far reaching than any of the other electrical work and so there was more scope for things to go wrong. Once all the other electrical issues had been resolved, I fitted the alternator belt and prepared to start the engine. Would it work or would it blow any of the other components?

Unfortunately I didn’t have a suitable ammeter to measure the theoretical maximum output of approx 60 Amps and so my testing was limited to measuring the voltage at the battery terminals with a multi-meter:

  • With the engine off, the terminal voltage should be approx 12.7v
  • When running at idle, the alternator should raise the terminal voltage to around 13.9v-14.3v
  • The terminal voltage should reach between 14.3-14.6v running at 2500 rpm

In theory if the alternator output drops from the last two levels then it points to the failure of one or more of the rectifying diodes. If it rises above 14.8v, then the 4TR voltage regulator unit is not limiting the maximum voltage and needs to be replaced to avoid overcharging the battery. However I also have to consider that any lack of output could also be due to the additional diodes introduced to self-energise the field winding.

It was a welcome anti-climax that the initial test appeared to be successful. Although I’ll need to do further checks to ensure it’s charging when the car is run for a longer period.

Jul 262012

Cooling on the original Series 1 cars was provided by a thin single two bladed cooling fan. This was uprated for the Series 2 with the introduction of twin four bladed fans. One of the popular upgrades is to improve the cooling by installing kits from Kenlowe or Coolcat, which are probably more suited to the stop-starting of today’s congested roads. I’m not sure if this upgrade is more targeted for the S1, so my aim is to restore all three fans, pick the better two for the rebuild and keep the third as a spare. I will then re-evaluate once I’ve driven the car for a period of time.

Motor body prior to shot-blastingThe alloy end plates were sent off to be ultrasonically cleaned while I renovated the motor body and internals. The renovation of the motor bodies ended up being a bit of a palaver and took several goes before I was happy with the end result. They were quite heavily rusted and after shot-blasting revealed quite heavy pitting. Rather optimistically, I thought this would be hidden when they were painted with silver Hammerite. What I soon learnt was that paint is not a good filler as the pitting was still clearly visible through the paint. Also I wasn’t happy with the colour of the silver Hammerite compared with the original finish which was a dark silver grey.All the bodies were quite badly pitted

Unfortunately Hammerite have stopped making the dark silver paint and it took quite a while before I managed to find a suitable equivalent, Rust-oleum paint code 7388.0.4. In the meantime the motor bodies had been shot-blasted again and the pitting filled with Isopon Metalik filler. The first attempt with the Rust-oleum was a disaster. The paint seemed to effervesce on contact, presumably to obtain the hammered effect, but the bubbles created remained in the final finish.

Colour difference between the Hammerite and Rust-oleum ... the wiper motor will now be re-painted to match!I finally managed to get a reasonable result by heating the spray can in hot water and the motor body in a low oven. This reduced the viscosity of the paint sufficiently to allow the bubbles to burst and then the paint to level sufficiently before it started to ‘skin’.

The photo to the left shows the motor body painted with Rust-oleum compared with the wiper motor painted in silver hammerite. I’ll now re-paint the wiper motor body in the darker grey.

The armatures were next to be tackled. The rusted iron parts forming the electromagnet were carefully wire brushed before being polished. Then Gtechniq S1 Smartmetal was applied to give a hydrophobic coating which hopefully might delay the onset of rusting in future. Finally the copper contacts were polished with good old Brasso, the gaps between the contacts cleaned out and new brush sets obtained, Lucas part BR1 743171.

Before …

and after

New brush sets

Armature condition as removed from the fan motor

Armature after cleaning and polishing

New motor brush sets purchased on eBay

The stator and the various bolts, washers and screws where then zinc-nickel plated using a kit purchased from Gateros Plating. The electroplating is surprisingly simple and good results can easily be achieved. The components were finally ready for the rebuild.

The rebuild process is, to use the overused terminology from Haynes manual, the ‘reverse sequence’ of the dismantling … but in this case it is as simple as that!

Plated stator

Armature refitted

Completed fan motor

The fan mounting brackets and the radiator cowl were originally a black, crinkle finish. Suitable crinkle paint spray cans are readily available but, while researching it, I found out that it’s possible to get a powder coating with a crinkle finish. After the disaster with the Rust-oleum hammered paint, I decided to go down the powder coated route.

However, it appears that the crinkle finish look must have fallen out of favour as I’d contacted almost all the local powder coating firms and none of them stocked it. I was about to give up when I found a small firm who had a small supply tucked away. A few days later and the parts were returned. I do hope that, after all this effort, the fans are up to the job!!

When the cars left the factory there were two plastic shields which covered the opening in the rear end plate for the electrical connections but these were missing. Fortunately SNG Barratt now remanufacturer these but I’m not convinced how effective they will be at keeping water out. I guess they’re better than nothing.

Cooling Fan with plastic shroud

Cooling fans – ready to fit

Before shot of the cooling fans

Fans and cowling restored to their former glory. Fingers crossed they're up to the job!

The before shot of the fans and shrouds

Feb 192012

Two new fans for a Series 2 were ordered from SNG Barratt. However when they arrived they were too large to fit in the radiator cowling. The diameter of the supplied fans was approx. 1″ bigger than the originals. They had sent me fans for an XJS V12, which would explain the incorrect part number being moulded in the fan centre! They looked identical apart from the increased diameter.

So I called Barratts to explain and they said they simply trim them to the correct size. I could either send them back for Barratts to resize or do it myself. I couldn’t be bothered with the hassle of sending them back so decided to do it myself.

6mm ply was used to fabricate templates to trim off the excessIt’s a well-known phenomenon that as soon as the dreaded ‘E’ word is mentioned the cost of parts rocket skyward, to whatever the vendor and, being of a cynical nature, the vendor community think they can get away with. The fans being a case in point. At the time, an XJS fan cost £15 while the E-Type fan cost over £30 – an eye-watering mark up! So it’s worth finding out if a part was common to other models/marques.

The plan to trim off the excess from the fans was to sandwich a fan between two plywood templates. Then run a router around the template so the smooth shaft section of the router bit would butt against the template and the cutting section cut through the excess fan blade below.

Birdfeeder base was an exact diameter match which made making the templates much easierAs luck would have it, the base of a garden birdfeeder had exactly the same diameter as the original fan. So this was used to cut out the templates, using the same method above.

It also became clear as work progressed that the plan was rather over-engineered. All that would be required was a correctly shaped upper template for a section a little wider than the fan blade. A blade could be positioned under this section and trimmed with the router.

A router was then used to cut off the protruding fan bladeThe fan could then be rotated until the next blade was under the same section and process repeated until all the blades had been cut to the correct length and profile. The blade ends were then lightly sanded to remove any remaining swarf and were then ready for fitting.

Feb 182012

Unscrewing the two long bolts provides access to the internal componentsOne of the great things I’ve found about the restoration of the various electrical components is that they were designed in an era before our ‘throw away’ society. Therefore overhauling the units is well within the capability of most enthusiasts. As with the fuel pump, the stripping down of the fan motors was very simple.

Having said that, the fans had been attached the wrong way round and no matter what I tried they would not come free. I tried using a small, hub puller type tool on the first fan. However all this achieved was to shear the nylon fan from its central metal fixing, which then had to be carefully cut off using a Dremel tool. So two new fans were added to the ever growing shopping list of parts required!

The fan motor casing consists of a square steel body clamped between two alloy end plates. After the two long screws have been withdrawn, the end plates can be prised from the body with a screw driver. These Lucas motors weren’t designed to be watertight as the rear end plates have openings for the electrical connections. So, over time, water ingress had taken its toll on the interior components.

Rear end plate

Corrosion within!

A rusted armature

A little persuasion was all that was needed to remove the end plate

The internals were fairly rusty ... probably not helped by the openings for the electrical connections in the end plate allowing water in

The armature had suffered worst

As the fan was still attached, the rotor (or armature), the front end plate and fan had to be removed as one. The only other parts within the motor are a wound stator and the armature brushes mounted in a plastic holder. The holder can be withdrawn by removing the two screws on the underside of the motor body.

Wound stator removal

Wound stator & brushes

Stator is just a push fit

Two central screws secure the stator housing

Stator housing can then be removed

The stator removed from the plastic housing

The stator can then be pushed out of the plastic holder. The brushes are loose fitting and can simply be pulled apart and lifted away from the holder. In the end neither fan blade could be removed intact. A Dremel with a cutting disc was needed to remove the metal fixing that remained stubbornly attached to the armature shaft. Once it had been removed the armature and front end plate could be separated.

A thrust washer sits between the front end plate and the armature. A similar washer isn’t necessary between the armature and the rear end plate. When the fan is operating, the fan blade produces a forward force on the armature pushing it towards the front end plate and away from the rear end plate. Therefore there is no load on against the rear end plate.

Thrust washer between the front end plate and the armature

Feb 022012

Series 3 fan motor?At some stage one of the cooling fan motors had been replaced with a round-bodied motor which I think must be from a Series 3, shown on the right. So the first task was to acquire a second motor which is correct for the Series 2. One of the vendors at the Jaguar International Spares day suggested that these occasionally came up on the eBay website.

I’d vaguely heard of eBay at the time and thought it was mainly used by people peddling tat and dodgy items. However needs must, so I logged on and started monitoring new Jaguar/E-Type ‘listings’. It took a while to get used to the ins and outs of their auction process. I’d soon lost count of the number of times I’d placed a bid days before the auction ended, only to find all the bidding happened within the last few seconds. I didn’t have time for that!

I must admit that subsequently I’ve been surprised how useful eBay has been, although I still think there’s a lot of tat on there – so buyer beware! Someone from the E-Type forum pointed me to an ‘auction sniper’ website which automatically makes bids for you, seconds before the auction ends, and so takes all the hassle away. Sure enough, someone listed two square bodied motors for sale but in need of complete overhaul.

Buckled boot lid frameOddly, at the end of their advert, they mentioned they were looking to get hold of a boot lid. At some point my car had had a slight shunt at the rear which had twisted the frame under the boot lid’s skin, which is just about visible in the photo. The bodyshop suggested that, although it could be repaired, it would probably cost as much as a new one as the skin would have to be removed to repair the frame.

As luck would have it, I had already sourced a replacement and so had the other one spare. I mentioned its condition to the eBay seller and that it might not be economical to repair but they seemed keen on cutting a deal – so a straight swap was agreed, with the transaction taking place late at night in a layby just outside of Brockenhurst!

Sourced motors with fan mounted back-to-front!The motors were indeed in need of a complete overhaul and for some reason had the white fans mounted back to front. I’m sure this wouldn’t have helped in the efficiency of the cooling and it certainly didn’t help when I came to remove them! Funnily enough, a few days later, an advert appeared on eBay for a basket case restoration of a red roadster, with my blue boot lid! As I said – buyer beware.