July 2013 – Chris Vine – Restoration of NNF 10H

Testing the fuel pump

Fuel Pump, Fuel System Comments Off

Jul 092013

It has been a long time since the fuel pump had been rebuilt, converting it from mechanical to electronic actuation in the process. Burlen Fuels offer an electronic conversion kit to overcome the known issues with point corrosion with the mechanical set up. While it would have been cheaper to buy a new pump, by reconditioning/converting it, I would gain a much better understanding of how it worked which might prove useful if there are issues in the future.

The electronic set-up had already been tuned to its maximum pumping speed, by rotating a Hall Effect fork. I just needed to check the flow rate was close to the designed 2.4 pints per minute by bench testing it with some paraffin before putting it on the car.

The pump raced when it wasn’t under load. So far, so good! However when the inlet pipe was placed in the bucket of paraffin it didn’t quite go as planned. It stopped immediately! I tried retuning the electric circuitry by repositioning the Hall Effect fork through its full arc of travel but it still refused to pump. It was a bit gutting having spent all that time and effort.

The technical department at Burlen Fuels thought it might be due to reverse pressure which would naturally slow the pump down. Although I wasn’t convinced as the outlet was simply pumping back into the supply bucket. I was running out of options and was starting to regret not buying a new pump!

I refitted the magnet attached to the end of the diaphragm spindle in the hope that this might be limiting its travel and therefore the strength of the pump. Eureka – the pump continued under load but at a much reduced rate, which would be expected.

The proof would be in the achieved flow rate which, over three tests, averaged out at 1.6 litres or 2.8 pints. Phew!

I was now happy that the pump was in working order and could be refitted to the car.

EDIS Megajolt electronic ignition

EDIS Megajolt, Rolling Chassis Comments Off

Jul 082013

The engine had been rebuilt by VSE with a replacement 123 Electronic distributor rather than refurbishing the original Lucas unit. However a chap, Ray Livingston, in the States had produced a kit for the 6 cylinder E-Types based on the Ford Electronic Distributorless Ignition System (EDIS), controlled by a programmable Megajolt Lite ignition unit.

A number of forum members had already installed his kit and reported on the quality of the machined components and improved running. In the interests of reliability, I decided to do likewise and order a kit as Ray was planning his final batch of kits and only a limited number remained. By chance another owner in Norway was looking for a 123 distributor so I managed to sell him my unused one.

The system has four main components: a trigger wheel & sensor, EDIS module, coil pack and the Megajolt controller. The trigger wheel is mounted to the front of the crank and has a series of teeth around its circumference, which pass close to the sensor. One tooth is missing to provide a reference point for the engine’s TDC. From what I can tell the sensor must use a Hall Effect device acting as a proximity detector to register each tooth as it passes the sensor head.

The signal from the sensor is interpreted by the Megajolt unit’s software to control the EDIS module and the coil pack. The coil pack has a HT output for each cylinder, however the spark for each cylinder is controlled electronically rather than mechanically, as in the original Lucas distributor. The Megajolt unit also has a vacuum input to enable the vacuum advancing of the ignition.

At this stage the key components will be installed but the final wiring and set-up will have to wait until the kit’s wiring loom is in place once the engine has been installed.

The instructions for the EDIS kit suggested using the LHD steering column bolt holes. The hole looked too small however it was due to a plastic cup being pressed into the hole and then painted over The Megajolt control unit is fitted to the bulkhead just behind the glove box. Rather fortuitously the mounting points for the steering column is exactly the correct spacing for the Megajolt unit, so the unused LHD column bolt holes are used to secure the unit to the bulkhead.

However I couldn’t screw in the lower mounting post as the bolt hole was smaller, unthreaded and blanked off. After much head scratching I decided to re-tap the bolt hole to the correct diameter. This wasn’t successful either and then it became clear what was wrong – the hole has been plugged with a plastic insert which just had to be pushed out!

The Megajolt unit can be connected to a PC’s USB port to programme the desired ignition timing curves although it is pre-programmed with standard curves out of the box. The connections won’t be accessible once the dash is in place, so I’m planning to add a surface mounted USB port to the rear of the glovebox.

The kit provides a replacement blanking plate for covering the unused LHD accelerator opening. The plate contains holes for the unit’s wiring harness and vacuum pipe. However I wanted to keep the installation a low key as possible and took a leaf out of the book of a member of the E-Type forum, and route these within the bulkhead and exit via the hole for the speedometer cable. All that would be required was a larger grommet.

The Megajolt controller is mounted to the LH side of the bulkhead using the LHD steering column bolt holes

The routing of the wiring harness and vacuum pip was routed within the bulkhead void and enters the engine bay via the hole for the speedometer drive

The wiring harness travels along the LH engine frame close to the EDIS module located next to the vacuum Reservac tank. The remaining components, the coil pack and trigger wheel & sensor, are mounted directly to the engine.

The coil pack is bolted to an aluminium bracket mounted directly into the hole for the standard distributor and so should be a reasonably unobtrusive modification.

The EDIS module is attached to the LHS engine frame near the vacuum reservoir

The coil pack mounting bracket locates in the vacated distributor drive hole

The coil pack trial fitted to the mounting bracket as it will have to be removed when the engine is installed

The fitting of the crank sensor and trigger wheel was the only tricky part of the installation simply because the positioning of the trigger wheel needs to be aligned to TDC. The sensor bracket is mounted using two of the timing cover bolt holes and is adjustable so the optimum gap can be set between the sensor and the trigger wheel.

However the sensor has to be removed to slacken the bolt to adjust the gap. This led to a rather iterative approach to setting it up but nothing to difficult.

The sensor bracket is mounted using two of the bolt holes on the timing cover. The end of the bracket is adjustable, allowing movement to vary the air gap to the trigger wheel

The adjusting bolt is hidden once the sensor is fitted so it was an iterative process to get the gap correct

A large torque wrench enabled the engine to be turned over more smoothly to accurately get TDC

The engine had just been rebuilt by VSE so the positioning of the TDC mark on the damper should be spot on but I decided to check anyway. Another eBay purchase was a dial indicator with a spark plug adaptor to accurately measure the engine’s TDC before the trigger wheel was fitted. Great in theory, however the adaptor’s plunger was too short to reach the piston head even at TDC.

Hmmm …. a high-tech replacement plunger was knocked up out of a short length of 3/16″ brake piping flared at one end and some masking tape to bring out to the bore of the adaptor. I found the easiest method of rotating by hand was to remove all the spark plugs and use a large torque wrench on the crank nut.

A dial indicator was used to obtain TDC and to check the TDC marking on the damper were correct

Once the trigger wheel was fitted, the air gap had to be checked by turning the engine over by hand to ensure it would not make contact with the sensor when the engine is running

After a little bit of adjustment, the trigger wheel and sensor had a sufficiently small air gap without making contact

Once I was happy that TDC had been achieved, the trigger wheel was temporarily attached to enable the re-checking the sensor gap for a full rotation. The last step was to check TDC again before the applying Loctite to the trigger wheel bolts one by one.

Fingers crossed everything is correct and the engine will fire first time!

Update: the engine fired up on the first turn of the key!!

Reuniting the engine and gearbox

Rolling Chassis, Transmission Comments Off

Jul 082013

My aim is to spend a long weekend in August (with the wishful thinking that it’ll be sunny!) to transform it from a bodyshell into a rolling chassis; installing the fuel system, rear suspension, engine/gearbox & ancillaries, front suspension and steering all in one hit. So I’ve got my work cut out to get everything ready in time.

The bonnet and front sub-frame need to be removed in order to fit the tiny radiator support brackets so I’m also going to remove the picture frame at the same time. It should then be possible to roll the engine and gearbox unit into place through the gap and avoid the hassles of installing the engine either from above or below.

The gap between the lobes at the lower front edge of the engine frames is only 22cm. However, if the water pump is removed, the engine is slightly narrower than this just below the height of the inlet manifold. The engine has been rebuilt by VSE with a new clutch fitted so I just had to attach the gearbox and bellhousing. However the reuniting of the transmission unit would feel like a major milestone had been reached!

The bellhousing had already been ultrasonically cleaned and just needed the rear oil seal inserted before being bolted to the gearbox. Three lock tabs are used to prevent six of the bolts from working loose. The remaining two bolts, next to the clutch fork, use safety wire instead.

I’d never needed to use locking wire on previous vehicles so needed to purchase a pair of safety wire pliers. Eventually I managed to obtain an old pair on eBay and some 0.81mm stainless wire.

The pliers were definitely a good investment, less so was the wire that I purchased. It snapped as soon as a few twists were applied. I hadn’t purchased annealed wire – dooh! After purchasing the correct type, it was a lot more successful! The main point is to make sure the wire passing round the outside of the bolt head puts tension on the bolt in a clockwise direction.

The fitting of the clutch release bearing and operating fork is all very straight forward. The fork can be inserted with the bearing attached which makes fitting the securing spring clips much easier. The clips are held in place by the curved end sitting in a slight dimple in the fork arm.

The push-fit spring clips secure the clutch release bearing to the operating fork. The curved spring end sits in a dimple in the fork

The pivot pin was lightly greased and aligned with the grub screw hole in the fork before inserting

A little Loctite was used on the grub screw which locks the pivot pin in position. A lock nut is then fitted on the grub screw.

The engine was already sitting on the DIY trolley which will be used to roll it into position once the front frames are removed. Hoisting the gearbox to the same level meant it was simply a matter of rotating it to align the drive splines. Once the splines were engaged the gearbox could be rotated back again to align the bolt holes.

Supporting the gearbox with the engine hoist made the job much easier

It was also very helpful to have the engine mobile to align the two units

The weight of the gearbox was used to help push the gearbox onto the clutch splines

The two bellhousing support brackets needed to be installed before the full weight of the gearbox could be released. Finally the flywheel cover plate was bolted on to finish the job.

I did make the mistake of fitting the clutch slave cylinder when fitting the bellhousing to the gearbox but had to remove it to fit the lower bolt for the support bracket. I’ll make the final adjustments of the clutch just before the engine is installed.

One thing I’m not sure about at this stage is the orientation of the four vertical bolts for the support brackets. One of the bolts is longer than the others and so I guess must be used to secure a bracket of some description. Another question for the E-type forum ….

Fitment of the bellhousing support bracket is needed before it can take the full weight of the gearbox

A major milestone reached - a completed transmission unit ready to fit. I hope it starts!!

The rear of the gearbox has a sprung fitting to absorb vertical movement

The gearbox is supported at the rear by a large spring between a mounting bracket and the gearbox. The spring damps the movement of the gearbox but allows for a degree of vertical travel. The spring ends sit in rubber mouldings. The mounting bracket also contains a rubber bump stop to limit the gearbox travel.

Handbrake caliper rebuild

Brakes, Rolling Chassis Comments Off

Jul 032013

Now the handbrake calipers have had been painted, all that remained was to rebuild them …. for the second time!

The service manual suggests the two rear calipers and handbrake mechanisms should be removed as single units. However this needs the half-shaft inner joints to be broken and the front springs/shock absorbers to be removed, which seemed unnecessary.

The components for the handbrake calipers and self-adjusting mechanism ready to be re-built

I found it much simpler to detach the handbrake mechanism from the rear calipers in situ and then remove them separately. So they won’t be re-united with the rear brake calipers until the refitting of the brakes into the IRS unit.

The handbrake system is self-adjusting using ratchet mechanisms to automatically compensate for the pad wear. The distance between the pad faces is determined by how far the caliper adjusting screw has been screwed into the ratchet gear.

When the handbrake is applied, the operating arm pivots on the pin attaching it to outer caliper arm. This effectively draws the caliper adjusting screw and attached inner caliper arm towards the outer caliper arm, resulting in a clamping force.

The pivoting action also allows the ratchet gear to move relative to the sprung pawl and the extent of movement is determined by the amount of pad wear.

As the wear increases, the movement becomes sufficient such that the pawl slides along the shallow slope of the ratchet gear tooth and its spring forces it to drop onto the next tooth.

The ratchet gear moves back relative to the pawl when the handbrake is released. However the pawl now engages with the steeper slope of the tooth resulting in a turning force on the ratchet gear.

This torque rotates the ratchet gear further onto the adjuster screw and therefore reduces the distance between the two pads. The photos above attempt to show the ratcheting process, although in reality the ratchet gear will only be tightened one tooth at a time.

All the moving parts a given a generous covering of Lucas green brake grease before the cover plates were added I’m not sure if there is a correct or recommended order for rebuilding the handbrake mechanism. I started with the internal parts of the operating arm; the pawl slots onto protrusions on the arm which guide and limit its travel. A tensioning spring attaches to the pawl and the other end to an anchor pin pushed through the operating arm.

The ratchet gear can then be installed which has a friction clip attached to its base. The clip provides sufficient resistance to stop the gear rotating when the pawl is gliding over the shallow tooth face. Once these were in place all the moving components were covered in high temperature brake grease.

The anchor pin for the return spring needs to be inserted into the outer caliper arm before the pads are fitted The operating arm could then be attached to the outer caliper arm. I found it easier to fit the operating arm return spring first which is attached at one end to an anchor pin pushed through the caliper arm and the other to a shaft in the operating arm.

Note: the spring passes through a protective cover so this needs to be positioned before the spring is hooked over the operating arm shaft.

The pivot pin between the caliper arm and operating lever was then inserted and fixed with a split pin. A slotted screw and nut then clamp the two protective covers to the operating arm.

Finally the inner caliper arm was attached to the caliper adjuster screw with another split pin and screwed into the ratchet gear to complete the rebuild.

The caliper adjuster screw is fixed to the inner handbrake caliper with a split pin

The completed handbrake mechanisms awaiting fitting