Fuel Line

MOT Hokey Cokey!

Jun 172015

I was keen to get the car roadworthy as soon as possible in order to drive it up to Nuneaton to have the hood put on. The difficulty at the moment is booking it in for work as it needs to coincide with dry weather!

Fortunately the day of the MOT was a fine sunny day enabling it to be dropped off as soon as the garage opened. It had been booked into a local Jaguar specialist the following day to have the suspension geometry set up. There was a chance, with a following wind, that it might be road legal by the weekend!

After a few anxious phone calls during the day, it became clear that they wouldn’t have time to complete the MOT. They hadn’t even had time to get to the bottom of the front carb running far too lean. The car was returned to base and a second MOT appointment made for the weekend.

Back for MOT attempt 2

I decided not to cancel the wheel alignment the following day, planning a quiet route for the 2 mile journey that was not frequented by the Rozzers. Alas the car only made it about ¼ mile before conking out. After all the years of effort, it was a particularly low moment. I was certain it was due to fuel starvation and that wretched air lock.

Luckily it was possible to get the car back in 100 yard stints, by waiting a few minutes between each spluttering halt. The second MOT was essentially a repeat of the first with no progress made and the car returned yet again, without any work done either on the tuning or MOT.

I took the opportunity to take the front carb off to look into why it was causing the front two cylinders to run too lean. The jet was properly centred but the float lever arm was found to be 3/16” off resting on the specified standard, a 7/16” rod.

More dismantling to investigate the front carb	The float lever should rest against a 7/16″ rod

A few days later it was back for the third attempt. The revised plan was to leave the carb tuning as historic vehicles aren’t subject to MOT emissions testing and just do the MOT checks. As they say, third time lucky …. this time it proved to be just that! It had passed the MOT and was ‘road legal’ … the first time in over 20 years!

A hurrah moment!
Passing the MOT

Although it had taken three trips to achieve, I’m considering it as passing first time! However there were obviously issues to address before it could be considered truly roadworthy. In fact, the MOT brake test has to be done out on the road due to the limited slip diff. They only just managed to perform the test and get it back to the garage before the fuel starvation ground them to a halt!

It was time to get some advice from my fellow trusted petrolists who had put in the IRS and come up with a plan. My worry was that it was the pipe running under that car that was a fault. Renewing it would require the IRS to be dropped and all that entailed – something I really wanted to avoid!

Their suggestion was to replicate the pipe run off the car using some flexible hose of the same bore. This would provide a more accurate flow rate that one could expect to achieve. If it is significantly different from the output of the under floor pipe, then it would point to this section being the root cause.

There were no kinks or collapsed bends in the pipe. The only other explanation was a blockage of some sort, but it’s a single length of (brand new) pipe which is open at one end and terminated at the other with a soldered connector that just mates with the bulkhead union. Hmmmmm …. could the soldered joint be causing a restriction and hence the reduced flow? It should be possible to poke a rod from the boot space through the union and into the pipe to get a feel to whether there was a restriction.

Rather embarrassingly, all my woes were of my own making. It wasn’t an air-lock, just my dreadful soldering! I’d almost completely blocked off the pipe by applying copious amounts of solder which had flowed into the bore. Worst still, I had compounded the error by not checking my handiwork before fitting the pipe.

My shocking soldering skills!	Fabricated drill bush worked fabulously!!

Further advice was sought on how best to removal it. Within no time at all, John had kindly arranged for a 3/8” BSP bolt to be machined/adapted to act as a drill bush to screw into the rear union. This would ensure the drill bit was perfectly aligned with the centre of the pipe and I would not be making matters worse by damaging the pipe itself!

The flexible hosing that had been used find out the expected flow rate was rigged up to pass fuel back up the wrong way to blow out any swarf. The same flow rate test was repeated with the re-bored pipe.

Testing the expected flow rate

A flow rate of 1.5 litres was achieved with the flexible pipe and surprisingly an even higher rate of 1.75 litres per minute is now flowing in the pipe. Compare that to the 250ml before the re-bore! I’m just so happy and relieved we got to the bottom of the problem and resolved it!

Not surprisingly this has cured the fuel starvation problems and the engine is running much more smoothly. Although it still needs a good tune.

A couple of items were corrected as part of the MOT – even though I’d checked every suspension nut and bolt, I had still missed putting on the lock wire on the radius arm bolts. I’d also left off the jockey wheel for the water pump tensioner and the alternator fan was slightly loose. So these were corrected.

Other recommendations were to ditch the original nylon style fuel pipe in the engine bay in preference for some flexible rubber hose and always carry a fire extinguisher!! The nylon pipes are very hard and I had noticed occasional leaks if they were knocked out of position. I’d rather have a traditionalist tut-tut than run the risk of a fire!

Even though the suspension geometry still needs to be set up, I couldn’t resist taking it out on the road for its first real spin. It was actually the first time I’d driven an E-Type and I wasn’t disappointed!

The first drive in the E-Type

Finishing engine bay & pre-MOT tasks

Air Filter, Alternator, Exterior Trim, Front Suspension, Fuel Line, MOT, Trim & Body Fittings 2 Responses »

Jun 162015

It feels as though the list of outstanding tasks is getting longer rather than shorter. So they have been prioritised into those required for the MOT and those that can wait. Due to the age of the car the MOT is essentially limited to checking the suspension, fuel/brake lines and lights. However, knowing the person doing the MOT, I’d asked them if they would cast a more critical eye over the whole car.

I’d been having trouble balancing the carbs and, although it’s not part of the MOT, I thought it best to have a second pair of eyes look over them. The front two cylinders are running too lean, even though all three carbs have been set to the standard reference point for tuning. So it will be tuned and the headlights aligned beforehand.

I also have concerns about the fuel flow. Last year the petrol tank had be put in-situ to just to start the engine for the first time. The tank was then removed to be painted and since then I noticed that the fuel flow seems to be rather low. Although I suspect I just hadn’t noticed the problem before.

Testing fuel flow from pump	Comparing the fuel flows per minute: 250ml at front bulkhead in bottle, 2litres at rear bulkhead in jug

The measurements of the amount of fuel pumped in one minute was taken at the rear bulkhead union and then at the other end of the pipe at the union on the front bulkhead. Although it’s not really a valid test, as there wouldn’t be any back pressure at the rear union, it did provide a feel for the drop off in flow – 2 litres per minute measured at the rear bulkhead union and only 250ml per minute at the front bulkhead union.

Suspicion is that it may be due to an air-lock created in the pipes. However advice from the forum suggested that a pump in good working order would have more than enough ummph to purge any air locks. Some further checks will be done to get to the bottom of the problem.

Longacre Camber/Castor Tool

The intention was to set up the suspension geometry myself and so I’d purchased a Longacre electronic camber/castor tool and a Trackace tool for the wheel alignment. The camber/castor tool has three legs which rest against the wheel rim with an accurate inclinometer attached in the centre. However I wasn’t thinking things through and had completely overlooked needing clearance for the central spinners.

The prongs on the legs don’t have the reach so I’ll have to have some made up. Unfortunately the MOT centre no longer has accurate electronic measuring tools for suspension set up. This will have to wait until after the MOT.

For some reason one of the dash indicator tell-tale lights had stopped working and the fault traced to the switches in the indicator stalk. It was easier to take the whole steering column off and investigate further on the bench. A loose back-plate on the switch mechanism had allowed the indicator contact to move about and be bent out of shape. So it was easily rectified.

The clamping bolts on the upper and lower steering column’s UJs had been taken off to aid the removal of the upper column. However, I’d become side-tracked and had not refitted them before attempting to tick off another pre-MOT task … making sure the speedo drive was working.

Needless to say, as I was turning round, after completing a successful straight 40 yard speedo run up the drive, the lower column dropped out of its splines. All steering was lost, blocking a now busy communal drive!
Apart from being stupid, it was a rather timely reminder! The complete suspension parts list was used as a check sheet to ensure every suspension nut and bolt was revisited to make sure everything was correctly torqued.

Mudguards, shields and undertrays
The various mudguards, shields and undertrays aren’t strictly necessary for the MOT. However they were fitted, as the horn relay needs to be mounted on the LH mudguard. John Farrell had produced a good guide to the locations and orientations of the five different types of brackets:

Front frame bracket locations	Five different bracket sizes

The first to be installed was the air in-take shield which is attached to bracket A at the top and B at the bottom. The leading face is also bolted directly to the frame. It’s worth noting that bracket E for the floor undertray needs to be put in place around the frame before the shield is attached. In fact it’s worth putting all the brackets in place before attaching any of the mudguards, shields and undertrays.

A & B brackets for air intake shield	Bracket E for undertray is fitted before in-take shield!

The bracket attachments to the frames are identical on both sides of the car, with the obvious exception of the air in-take shield. The torsion bar shields are attached by three brackets – the rear two have the tab with the bolt holes pointing upwards while the front one points downward. Note: the middle bracket on the LH frame is also used to secure the bottom of the exhaust heat shield.

Alternate rear torsion bar shield & undertray brackets	Shield bracket also attaches bottom edge of exhaust heat shield	Front torsion bar bracket (L) and mudguard bracket (R)

The two floor undertrays are simply bolted in place. Although the right hand undertray has a cut out with a separate cover to provide access to the oil filter.

Left hand undertray	Right hand undertray, without oil filter access panel

There wasn’t any point in completing the fitting the mudguards because they will have to be removed to provide access to set the camber and castor. So at this stage they were only bolted to the sill end panel and attached at the front to a side frame bracket. At least this allowed the horn relay to secured for the MOT. Normally the alternator and aircon (when fitted) relays would also be attached to the LH mudguard, but by modifying the alternator it no longer requires a relay.

LH mudguard temporarily in place just for the MOT	Location of horn relay. Alternator relay isn’t needed

Air Filter
I was regretting not trial fitting the air filter earlier. The new fuel pipe I’d made protruded too far from the face of the toe box, hitting the air filter. Fortunately it was possible to remove a short length from the filter end which resolved the fitting problem but re-introduced all the air bubbles causing the air locks.

It took a while to work out the best method of fitting the air filter element, canister lid and air plenum. Once the canister lid and rubber grommet are in place, there wasn’t sufficient access to pull the grommet up around the lip of the plenum chamber. Eventually I found the best solution was to connect these components off the car and then fit and remove as a single unit.

Filter canister was hitting the fuel pipe	Adjusted fuel pipe now narrowly misses it	Fitting canister lid first didn’t work

Alternator testing
Another task was to ensure the alternator was charging properly when the engine was running at higher revs. The outcome wasn’t as I’d hoped – it wasn’t charging at all, measuring only 12.5 volts! The converted alternator is now self-energising – the AL terminal, normally used for monitoring the alternator output via the ignition warning light, now provides a DC supply to power the field coil. Finding earth via the field coil through the 4TR voltage regulator.

Testing the alternator

The AL terminal was reading zero voltages at idle rather than the expected 14.3 volts! The voltage regulator controls the alternators output to avoid ‘run-away’ where its output would continue increasing until it burnt out the various internal components and/or windings. Increasing the voltage across the field coil increases the alternator output voltage, which in turn increases the field coil voltage.

The 4TR regulator acts as a fast-acting on/off switch. When the output of the alternator increases above a determined voltage (around 14.6v), the regulator switches off the current flowing in the field coil and therefore the alternator voltage drops. Once it has dropped sufficiently, it switches the current in the field coil back on and the alternator output starts to increase, until the cycle repeats.

A passing peacock offered
no helpful advice!!

Suspicion fell naturally on my modifications to the alternator and also the 4TR regulator, which are known to be fragile. A faulty voltage regulator can easily be identified by removing it and using a jumper lead to connect the F and ‘-‘ leads in its connector.

If it is faulty, starting the engine will cause it to start charging (indicated by the alternator output voltage or the battery gauge rising above the battery’s normal 12.3-4 volts) If so, the engine should be switched off immediately and the 4TR unit replaced. It was a great relief to find it was the 4TR unit that was at fault and not my handiwork! A replacement was ordered which confirmed the diagnosis and it is now working as expected.

Crossing fingers
I didn’t want to drill holes in the bodywork for side mirrors and so some clamp on mirrors have been attached to the window frames. That just about completed all the pre-MOT jobs.

Clamp on side mirrors fitted	After all this time, it’s finally ready for the MOT!!

For the first time in several decades, 1R1421 hit the road …… on it’s way to the MOT centre! …. fingers firmly crossed!!

Finishing off the fuel system

Fuel Line, Fuel Line and Hydraulics, Fuel System, Fuel Tank 1 Response »

Feb 092015

Even though the engine was started last year, there were a number of outstanding issues and tasks to complete the fuel system. The most concerning was the new fuel tank didn’t fit! At the time, it was just left in situ and the fuel lines connected while the engine was fired up. Refitting had to wait.

Carburetter Overflows
First, however, was the replacement of the three carburetter overflow pipes. At some stage these had been replaced by shorter pipes. Functionally there was nothing wrong with them but they should come together near the oil filter and be held in place by small clip.

The short pipes will be replaced	New pipes from Burlen Fuels

Everything is available from Burlen Fuels although they offer two lengths of overflow pipe: 19” and 25”. The length of the shorter pipe would have been marginal for the rear carburetter so I opted for 25” pipes …. just in case. With hindsight, 19” pipes should have been ordered for the front two carburetters as the distances are much shorter.

I had decided to replace these once the engine had been fitted. While it would have been much easier to shape them when the engine was sitting on its trolley, I was concerned that guesstimating suitable clearances to engine frames etc would be too easy to get wrong.

Several hours later, ready for fitting	The clip securing the ends of the pipes

The only slight difficulty was the overflow for the rear carburetter as access was limited once it had been shaped. The jury is still out on whether it would have been better to do this job with the engine out!

New bulkhead fuel line
Another fuel problem encountered when the engine was started was the fuel line had gone into the filter housing cockeyed, causing it to cross-thread and leak. The temporary solution had been to reverse the fuel filter however the root cause was the bulkhead section of pipe, which needed to be remade.

These earlier troubles had been caused by a combination of the pipe not being square onto the filter housing and the brass fitting supplied in the fuel line kit. The fitting had an un-threaded shoulder section which then only allowed a turn or two of thread to engage before it bottomed out on the olive. A replacement was found that was threaded to the end.

The vacuum tank needed to be removed to provide sufficient access to offer up the new pipe as it was bent into shape. I wasn’t happy with the original routing of this section of the fuel pipe, as the P-clip securing it to the bulkhead, pulled the pipe hard against the paintwork where there is an ‘X’ indentation in the toe-box.

Original routing	Now routed higher on toe-box	Upturn no longer fouls bodywork

By inverting the P-clip, so the pipe was supported by the clip rather than being hung from it, the pipe is routed above the ‘X’. The other problem that was cured from my first pipe attempt was the length of the downward run to the union had been cut too short, causing the upturn bend to hit the bodywork.

Installing the fuel tank …. 4th time lucky!
I take my hat off to the original fuel tank fitters, who must have developed quite an efficient technique for getting the fuel tank in place on the production line. Although, with trails and tribulations I had trying to get the tank securely fastened, it was becoming a less daunting challenge with each fitting attempt. Perhaps there is some truth in the joke about E-Types being built up around the fuel tank!

First a few minor tasks were completed. The sump was checked for pinholes as it is prone to corrosion and fitting the missing metal fuel filter at the base of the pick-up pipe. The tank and surrounding bodywork was then covered with plenty of sheets and masking tape to try and minimise the damaging the paintwork.

Fortunately sump was pinhole free	Pick-up pipe – now with filter

The initial problem is the aperture of the boot space is less than the width of the seam-welded lip around the circumference of the tank. Tilting the front edge of the tank downwards doesn’t enable the lip at the rear to clear the flange for the boot boards.

There’s a gap in this flange where the boot lock attaches. So the only option I could see was to remove the lock and then tilt the tank sideways, feeding the lip through the gap vacated by the boot lock.

The most obvious approach was to raise the right side of the tank and feed it down to the left since the tank occupies the left side of the boot. However this first attempt failed as the sump attachment is proud of the base of the tank and comes into contact with the floor strengthening sections, halting progress.

So the opposite was attempted, feeding down to the right. The aim was then to shuffle the tank all the way across to the left once the flange had been cleared.

Yet just as it was nearing that point, it fouled somewhere else! It wasn’t immediately obvious what was causing the problem but eventually it was traced to the clip for the boot board. Fortunately it’s only riveted in place and could be removed.

The offending boot board clip	Eventually the flange was cleared

Finally the tank was below the flange and could be manoeuvred into position once the various filler and breather pipes were attached. The boot lid drainage pipe caused quite a bit of aggravation as it had a tendency to spring out of place and push the tank away from the mounting points.

Corner bracket should have captive nut	Breather tubes for later S2 tanks	So near, yet so far

However, until now, I hadn’t noticed the replacement forward mounting bracket simply had a nut welded to it, rather than a captive nut within a cage. The lack of adjustability provided by a captive nut meant it was impossible to get the distance between the two leftmost mounting points to match those on the tank.

One of the mounting hole in the tank had to be enlarged by around 3mm to get the tank to fit The tank had to come out in order to enlarge the mounting hole in the tank by a couple of millimetres. Unfortunately I wasn’t able to rig up something to measure the difference in centre distances with any degree of accuracy. The tank was re-fitted but it was still a millimetre out, so it was back out for some more fettling.

This time it fitted! Well two of the three mounts did. The third bracket is moveable as it can slide in elongated holes and so would be doddle in comparison. How wrong could I be!

The original bracket had one stud missing and two of the other studs had lost most of their thread due to corrosion. It didn’t feel it was worth trying to salvage it as new ones are inexpensive. So I made the mistake of buying a reproduction bracket – not once but twice!

Damage to original bracket	Neither repro brackets were usable

The first wouldn’t fit because the studs were too far apart to mate with the holes in the bulkhead. To make matters worse, I only found this out after it was powder coated. The second was ordered from a different supplier. The studs were in the right place but much smaller diameter. However, as with the previous bracket, they both just had a nut welded in place rather than the captive nut.

This mount requires both lateral and fore/aft adjustability to have any chance of alignment with the bolt. Lateral adjustment is provided by the elongated holes for mounting the bracket. The movement of captive nut provides the fore and aft adjustment. Neither of the repro brackets were useable.

Its times like this that I do get frustrated with all the suppliers – it’s just lazy ‘that’ll do’ mentality and often it would be as hard to get wrong as it would right. Although I really should have spotted the differences when they were purchased. The original one will be repaired, which is what I ought to have done in the first place. Another lesson learnt!

Fuel Sender – stumped but fixed
For some reason the low fuel light on the dash wasn’t working, yet the fuel gauge was fine. The fault was traced back to the fuel sender unit, which has a removable cover plate. So it was easy to gain an understanding of how it worked to control both the fuel gauge and warning light.

W & T terminal mechanisms	Low fuel light contact strip

As would be expected, the unit uses a rheostat to vary the voltage drop across the fuel gauge and the warning light is simply a contact switch. However I hadn’t realised they were two completely separate circuits, sharing a common earth – the sender unit housing.

As the float arm rises and falls with changes in fuel levels, its pivot rotates through approximately 80 degrees. Two slider contact arms are attached to the pivot within the unit and therefore follow the same arc. They are also in contact with the sender housing and so are the electrical contact to earth.

Fuel Gauge
One of the sliders runs along the edge of tapered coil of resistance wire which is connected to the exterior T terminal. When the tank is full and the float is raised to its maximum, the full length of resistance wire lies between the slider and the T terminal – a total resistance of 196Ω.

When the tank is nearly empty and the float is at its lowest, the slider will have moved shortening the length of resistance wire between the two. At empty, the rheostat resistance is 18Ω. The fuel gauge is calibrated to display Full and Empty for these two resistance values.

Low Fuel Light
There’s a copper contact strip on the inside of the cover plate which has a small diagonal break in the copper so the two ends are electrically isolated from each other. The W terminal, connected to the gauge, makes permanent contact with one end.

When the tank is full the second slider arm is in contact with the other end of the strip and moves towards the W terminal contact as fuel is consumed. The slider eventually moves across the gap making electrical contact with the W-terminal, completing the path to earth and switching on the warning light.

I couldn’t work out why it wasn’t working. The multi-meter confirmed the internal connections were working correctly. Yet the switching wasn’t evident at the external spade connector. It didn’t make sense as a metal rivet connects the internals with the external spade terminal.

Checking with the multimeter confirmed that somehow the rivet and the external spade terminal were electrically isolated from each other. A dab of solder solved the problem but I still can’t fathom how they could not be in contact with each other.

Once it’s up and running, I’ll fill from empty to find out how many litres of fuel are in the tank when the light comes on.

The tank has since been filled from empty and it takes exactly 12 litres (2.6 gallons) before the warning light goes out. So there should be around a 50-55 miles range once the warning light comes on.

Fuel Line, Fuel System No Responses »

Jun 052013

The fuel lines within the boot space are made of a hard, opaque, white nylon and exit via a union mounted on the far right of the rear bulkhead. Metal piping is then used between the union, around the rear axle mounting panel and along the underside of the chassis, to the fuel filter within the engine bay.

Fuel filter just needed to be cleaned up and the filter replaced

Dismantling revealed only small amounts of deposited fuel residue

The filter and union just needed to be cleaned up. So the alloy body had the ultrasonic cleaning treatment to remove the fuel residue and the other parts zinc-nickel plated. Leaving the difficult part of bending the Cunifer fuel pipe ….

Ultrasonic cleaning brought the filter lid up nicely

Cleaned and re-plated; the rear bulkhead union and filter assembly

A 5/16″ diameter pipe is used for the fuel line so it is less forgiving than the brake pipes if minor tweaks are needed. The difficulty is that the entire section around the rear suspension cage needs to be bent into shape before it can be offered up. This involves bends in a variety of different planes, a sharper bends to then pass along the underside and ensuring the pipe passes through two retaining clips.

Fortunately I still had a slightly deformed original pipe to use as a template otherwise it would have been an altogether harder task. Again, as with the brake piping, I deviated from the original routing around the bolts for the torsion bar reaction plate. The only bit I’m not entirely happy with was the small section of pipe from the inline union in the engine bay to the filter which ought to be more horizontal. Still, it’s hidden by the vacuum tanks so shouldn’t stand out.

The good thing is that, now this pipe is in, the completed rear suspension cage can be fitted. Half way to a rolling chassis!!

Below are a few photos of the pipe routing: