LotusElan.info

March 2004

1st March 2004

Had the car booked in for an MOT at a local garage.  Arrived at 11:30am prompt.  After examination, the car failed on four points:

Drove the car back home and nearly ran out of fuel on the way. Fortunately I had a 6 litre can of fuel in the boot.

Corrected the faults and took the car back for 1:30pm and following a brief examination, left with a new MOT.  38918 miles recorded. I think that's probably more like 138918 miles.

Next visit was to my local DVLA office to change the status of the car to 'Historic Vehicle' and get a new tax disk.

Finally I drove off for the first time in order to get the tracking sorted.  Stopped off on the way to to fill up with fuel.  Poured in 40 litres of Super Unleaded which came to appox 2" below the breather on the filler neck.  Gauge read between 3/4 and full.  I'd guess that I could fill up to the breather in order for the gauge to read full.  38922 miles recorded on the clock.

Drove the car for approximately 40 miles.

Fitted the Electronic Ignition and booked the car in at a local  tuning specialist.

Obtained two new door handles and locks from a local Austin specialist. Sadly the keys are different for each side of the vehicle but I may be able to re-key them at a later stage.

Adjusted the throttle cable length to correct the engine idling too fast.

Discovered why the alternator was not charging.  The ignition warning light was connected to earth and not a switched positive, therefore, the alternator was not putting out any power to charge the battery or supply any of the components.  Rewired the the warning light and it now comes on when I turn the key and off once the engine is started.  I also see a positive reading on the ammeter.

Roughly reset the timing and balanced the carbs as the car was running very poorly. Turned the fuel mixture screws in 1/4 turn as the plugs were very black.

Flashed over the bare patch on the bonnet with some Citroen Meteor Grey paint to tidy it up a bit.

Removed the drivers door card in order to examine the locking mechanism.  After swapping our the handles for new, I noticed that the rod connecting the locking mechanism to the inner handle is about ½" too short.  This causes the mechanism to return back to it's unlocked state after turning the key or depressing the inner handle. It looks like I may need to adjust the length of the rod.  However before making any drastic measures I'll examine it further and get a second opinion.

Drove the car to Derby and back, collecting a new interior mirror along the way. The old oval shaped mirror did not give particularly good coverage of the rear screen and the adjusting screw was damaged making it impossible for it to stay in one place.

Changed the oil & filter.

Took the car in to Peacock & Purvey for a tune up.  Car came back better than it have gone in, but the engineer told me that there was a blockage in the rear carb, causing problems with the no.3 cylinder.  I removed the carb, and found a thick layer of sludge in the bottom which I cleaned out.  Attempted to clean out any blockage by blasting compressed air through the progression hole inspection cover.  On re-mounting the carb, this did not appear to have made any difference.

Had another look at the drivers door lock.  On closer investigation, I noticed that I could bend the link rod where it's bent near the inner handle in order to increase it's length.  This done, the lock worked correctly.  Whilst the door card was removed I started to repair the hole made by a previous owner for a keyhole.  Also took the opportunity to repair some other holes

Started to investigate why the Rev counter gave double the correct reading.  Cut the wire feed it and removed a loop from the induction feed.  This seemed to have the effect of giving no reading at all.  Put the second loop back in and still got no reading.  Pulled the rev counter out of the dash in order to scrutinize further.  When I removed it from the original dash I'd  noticed a rattle, so, I removed the back cover to find out what was causing it.  The rattle was caused by what appeared to be the remains of a capacitor the had exploded.  Before doing anything else, I'll have to try to get a circuit diagram so that I can replace the faulty component.

Removed the carbs in order to give them a thorough clean (again).  The rear carb that had been removed the previous week had more sludge in it again.  I was expecting the front carb to be virtually choked, but it wasn't as bad as I thought it would be.  Whilst I was at it, I also checked the spindles for twisting by checking that the butterflies were at exactly the same position by viewing through the progression hole inspection cover on each carb.  Both carbs appeared to be fine, however, the rear carb did have a slightly sticky throttle.  This was corrected by slackening off the spindle nuts and re-entering the butterflies.  I also did the same for the front carb as, after shining a torch down the chokes, the butterflies appeared slightly off centre.

Whilst the carbs were in the workshop, I also removed the mechanical fuel pump and replaced with a blanking plate as this is to be replaced with a Facet solid state fast road pump.  Replaced the old carb fuel connection with a new braided hose.

Removed the Pedal Box in order to give it a thorough overhaul.  I had previously given it a lick of paint and a squirt of oil, but having now driven the car for a while, I find the amount of lateral travel in the pedals  was increasing, particularly the accelerator pedal.  The shaft and both bushes that support it are badly worn.

Took the pedal box to my father -in-law to see what he could do with it.  After examination, he decided that the best option would be to ream the pedal bosses out to 9/16" and make a new over-size shaft for the pedals to swivel on.  Unfortunately, the clutch pedal boss was so badly ovalled, a new boss needed to be made and welded to the pedal stem.  The box bushes were also reamed to suit the new shaft.  Once done, the lateral pedal movement was virtually eliminated.

Started to fit the electric fuel pump in the boot.  I'm not entirely happy with its initial location, so I may move it to a more satisfactory position later on.

Test drove the car and found that once warmed up, it idled and ran much better than before.  The engine is now much more responsive and settles quickly back to the correct idle speed.  There's a slight hesitation somewhere around the 1500 - 2000 rpm mark which I'll look at later.

Having found a circuit diagram for the tach on the web, I removed it again for repair.  After following the diagram I found that the faulty component was a thermistor and not a capacitor after all.  Sadly the only component value not identified on the diagram was the one I wanted.  Scratching my head and wondering why I spent all my electronics lessons at college playing Chucky Egg on a  BBC computer, I tried to recall the formulae for calculating the resistance of resistor in a parallel circuit.  Giving up on that one I had another trawl through the web and found it:

Total resistance  = (r1 x r2) / (r1 + r2)

r1 = thermistor of unknown value

r2 = green blue black = 56Ω

Checked out the Maplin site to find that they listed 5 different value thermistors: 4k7Ω to 150kΩ.  Popped the values through the formulae only to find that they all come out at 55 point something ohms; hum - something doesn't seem quite right here!  Went off to Maplin anyway and bought the only thermistor that they had in stock. Removed the old component and soldered in the new one.

Sat in the car and calibrated the Rev counter against my Gunsons test meter whilst keeping the engine at a steady 3000rpm.  After further head scratching I began to wonder if the original thermistor was actually a lower value than r2 and helped to protect the meter circuit against overload as well as compensating for temperature changes, thus explaining its unfortunate demise.  However this didn't explain why the meter was reading double the correct value.  The biggest problem here is that it's been nearly twenty years since I did any of this stuff and I don't know what I'm doing!  I think that the best option would be to have a look at a working rev counter and check the thermistor out in that.

Moved the fuel pump and regulator to the rhs of the boot.  This seemed much safer from the risk of the currently unsecured spare wheel hitting it.  Sadly is didn't reduce the noise level.

Connected up the heater fan and interior light. I don't know what everyone complains about ......  The heater is far better than the one on my Land Rover.

Attempted to find the annoying squeak from the rear rhs transmission.  Ensured all the transmission bolts were tight and secure. Also took the opportunity to secure the calliper bolts with stainless steel wire.  Still could not locate the squeak.  It's possibly one of the brake pads just catching the disk as it rotates - further investigation required.