A Few Problems
Due to forgetting to undo the earth point under the nearside of the whale tail and dash several problems arose.
While lowering the chassis it tensioned the earth leads and literally pulled the bobbin out of the fibre glass body it also pulled on the main loom and yanked the solder tags off two earth cables.
1.To replace the bobbin I had to repair the body with woven fibre glass matt and make a support underneath out of stainless steel while it set, release agent was needed so that the glass did not stick to the stainles support, this was a most awkward job as access was severly limited but got there in the end.
2. When finally checking the electrics as a result of the loom being pulled neither the Indicators nor Central Locking was working. Dash removal was necessary to find the problems, on both the indicator relay and the central locking control unit spade terminals had pulled off due to the loom being stressed.
3. The car refused to start, removing a spark plug indicated that fuel was not reaching the cylinders. Checking the bleed valve on the injector rail did not show any pressure or fuel. The fuel pump appeared to prime when turning on the ignition so that seemed OK so I decided to check the main fuel line from the injector rail back to the filter, this appeared free as I was able to blow fuel back out of the filter. This seemed to rule out everything but I noticed that when turning on the ignition that the pump missed some priming periods so substituted a new pump and it primed every time suspecting the old pump after 28 years had become intermittent. Looking further I noticed that the high pressure fuel line had been trapped between the body and chassis this went unnoticed when lowering the body back on the chassis. The new pump primed every time the ignition was switched on but there was still no pressure in the injector rail. I suspected the pressure regulator but was completely wrong the pressure regulator was fine the problem was my self! I had inadvertently swapped the connections for the high pressure and low pressure fuel lines, thanks to Belle on the TVR Forum for suggesting this fundamental error. The original fuel pump had its polarity identified -ve and +ve the replacement is marked red and black but in common with many other owners experience some of these are incorrect as the earth connects to red and the +12 Volts to black. If you are not getting fuel to the injector rail try reversing the connections.
4. The off side electric window was inoperative although the near side was fine, this took a while to trace but again was something simple. Unknown to me the plug/sockets on the rear of the window lift switches are not keyed so when replacing the plug during reassembly I had replaced it upside down, a 50/50 chance of getting it correct, an indication was the switch bulb alight even though the car lights were off. During assembly one of the fixing bolts that are Araldited to the panel dropped off so had to be re-glued I used J-B weld that I prefer to Araldite.
While lowering the chassis it tensioned the earth leads and literally pulled the bobbin out of the fibre glass body it also pulled on the main loom and yanked the solder tags off two earth cables.
1.To replace the bobbin I had to repair the body with woven fibre glass matt and make a support underneath out of stainless steel while it set, release agent was needed so that the glass did not stick to the stainles support, this was a most awkward job as access was severly limited but got there in the end.
2. When finally checking the electrics as a result of the loom being pulled neither the Indicators nor Central Locking was working. Dash removal was necessary to find the problems, on both the indicator relay and the central locking control unit spade terminals had pulled off due to the loom being stressed.
3. The car refused to start, removing a spark plug indicated that fuel was not reaching the cylinders. Checking the bleed valve on the injector rail did not show any pressure or fuel. The fuel pump appeared to prime when turning on the ignition so that seemed OK so I decided to check the main fuel line from the injector rail back to the filter, this appeared free as I was able to blow fuel back out of the filter. This seemed to rule out everything but I noticed that when turning on the ignition that the pump missed some priming periods so substituted a new pump and it primed every time suspecting the old pump after 28 years had become intermittent. Looking further I noticed that the high pressure fuel line had been trapped between the body and chassis this went unnoticed when lowering the body back on the chassis. The new pump primed every time the ignition was switched on but there was still no pressure in the injector rail. I suspected the pressure regulator but was completely wrong the pressure regulator was fine the problem was my self! I had inadvertently swapped the connections for the high pressure and low pressure fuel lines, thanks to Belle on the TVR Forum for suggesting this fundamental error. The original fuel pump had its polarity identified -ve and +ve the replacement is marked red and black but in common with many other owners experience some of these are incorrect as the earth connects to red and the +12 Volts to black. If you are not getting fuel to the injector rail try reversing the connections.
4. The off side electric window was inoperative although the near side was fine, this took a while to trace but again was something simple. Unknown to me the plug/sockets on the rear of the window lift switches are not keyed so when replacing the plug during reassembly I had replaced it upside down, a 50/50 chance of getting it correct, an indication was the switch bulb alight even though the car lights were off. During assembly one of the fixing bolts that are Araldited to the panel dropped off so had to be re-glued I used J-B weld that I prefer to Araldite.
Heater panel
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Araldited mounting lug
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5. Replacing the engine mounts looked to be a simple job and with the car on a ramp and using a jacking beam to take the weight of the engine it would be relatively straightforward but as my jacking beam had an hydraulic leak I had to tackle this on the garage floor. One of the most awkward jobs I have ever tackled as there is little room to access the various bolts.
To gain access the car should be supported on axle stands at the front and both wheels removed the engine then needs to be supported under the flat part at the front of the sump with a trolley jack. Access is still very tight though and I found it easier to remove and refit the complete assemblies with the mounts bolted on, the rusty brackets can then be painted. Note that spacers are sometimes fitted under the mounts to keep the engine level, mine were on the offside but some cars differ. The brackets have elongated holes where the mounts are bolted this allows some degree of movement after assembly so that the engine can be positioned centrally to give the same clearance for each exhaust manifold to the inner wings so leave the mount nuts slack to allow this movement. Unless you have unlimited patience and tiny hands I would let a garage do this job.
To gain access the car should be supported on axle stands at the front and both wheels removed the engine then needs to be supported under the flat part at the front of the sump with a trolley jack. Access is still very tight though and I found it easier to remove and refit the complete assemblies with the mounts bolted on, the rusty brackets can then be painted. Note that spacers are sometimes fitted under the mounts to keep the engine level, mine were on the offside but some cars differ. The brackets have elongated holes where the mounts are bolted this allows some degree of movement after assembly so that the engine can be positioned centrally to give the same clearance for each exhaust manifold to the inner wings so leave the mount nuts slack to allow this movement. Unless you have unlimited patience and tiny hands I would let a garage do this job.
Near side mount
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Off side mount
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The engine must be assymetric as the off side mount has a substantial spacer to lift the engine.
6. In spite of taking many photos of the cars layout before dismantling I found that when installing the exhaust system that the high pressure fuel line was lying on the wrong side of the chassis rail and thus adjacent to the silencer, hardly an ideal arrangement so this had to be re-routed to the outside of the chassis rail. There is just enough room between the rail and the body to house the high pressure fuel line and the closed circuit breathing line from the filler neck to the carbon cannister. Due to the limited space I used copper tube for much of this breather run.
As plastic tie-wraps are used extensively throughout the car to secure fuel lines, cables etc. to the chassis rails I opted to use 6mm wide tie wraps as they are rather more rugged than the originals. It is surprising how many are used during a restoration.
7. To check that the speedometer was working I drove the car a short distance but immediately noticed a tap, tap, tap coming from the rear end, so back on the 4 post to investigate. One of the teeth on the speedo toothed wheel on the differential input flange had been fouling the magnetic sensor, I expected the sensor to be now scrap but suprisingly it tested OK on the bench giving a small AC voltage kick when a steel ruler was passsed over the sensor. As the offending tooth needed to be bent back in line I turned a snug fitting Delrin disc to fit inside the toothed wheel and act as a guide, by careful tapping with a pin hammer and punch the tooth was brought back into line. Using an outside caliper each opposite pair of teeth were measured to check all was true. The toothed wheel and sensor were re installed leaving a 15 thousand of an inch gap between the two as an initial setting. l suppose the toothed wheeI must have been bent during restoration so they need to be stored carefully. To check it was now working the rear was supported on axle stands allowing the rear wheels to rotate freely and the speedo functioned OK, I did notice that it only starts reading after about 10 mph. that is probably normal.
6. In spite of taking many photos of the cars layout before dismantling I found that when installing the exhaust system that the high pressure fuel line was lying on the wrong side of the chassis rail and thus adjacent to the silencer, hardly an ideal arrangement so this had to be re-routed to the outside of the chassis rail. There is just enough room between the rail and the body to house the high pressure fuel line and the closed circuit breathing line from the filler neck to the carbon cannister. Due to the limited space I used copper tube for much of this breather run.
As plastic tie-wraps are used extensively throughout the car to secure fuel lines, cables etc. to the chassis rails I opted to use 6mm wide tie wraps as they are rather more rugged than the originals. It is surprising how many are used during a restoration.
7. To check that the speedometer was working I drove the car a short distance but immediately noticed a tap, tap, tap coming from the rear end, so back on the 4 post to investigate. One of the teeth on the speedo toothed wheel on the differential input flange had been fouling the magnetic sensor, I expected the sensor to be now scrap but suprisingly it tested OK on the bench giving a small AC voltage kick when a steel ruler was passsed over the sensor. As the offending tooth needed to be bent back in line I turned a snug fitting Delrin disc to fit inside the toothed wheel and act as a guide, by careful tapping with a pin hammer and punch the tooth was brought back into line. Using an outside caliper each opposite pair of teeth were measured to check all was true. The toothed wheel and sensor were re installed leaving a 15 thousand of an inch gap between the two as an initial setting. l suppose the toothed wheeI must have been bent during restoration so they need to be stored carefully. To check it was now working the rear was supported on axle stands allowing the rear wheels to rotate freely and the speedo functioned OK, I did notice that it only starts reading after about 10 mph. that is probably normal.
Toothed wheel reference guide
8. Both rear brake callipers were reconditioned units bought a few years ago but the offside started to leak, on inspection the dust seal and piston seal were both severely damaged it looked as though whoever reconditioned it did not know the correct way to insert the seals and forced them ripping both in the process. A rebuild kit was purchased from Frentech Brakes ( a most helful supplier) who supplied all the seals and new pistons. I have described the rebuild process here.
9. After nearly a year from starting the restoration the car refused to start. Fuel was reaching the engine but the spark was intermittent. +12 volts was reaching the coil so the immobiliser and associated wiring was OK. All the usual culprits namely: The ignition amplifier, the coil, the distributor cap, the rotor arm were all replaced but the fault remained,the only other possible was the distributor electronic trigger assembly. This is often called a Hall effect device but this is incorrect, it is simply a rotating steel trigger wheel with 8 pips that passes closely to a coil and magnet assembly. Each time a pip passes the coil it creates a pulse that triggers the ignition amplifier that in turn activates the coil to produce the high tension feed via the king lead to the distributor cap.
9. After nearly a year from starting the restoration the car refused to start. Fuel was reaching the engine but the spark was intermittent. +12 volts was reaching the coil so the immobiliser and associated wiring was OK. All the usual culprits namely: The ignition amplifier, the coil, the distributor cap, the rotor arm were all replaced but the fault remained,the only other possible was the distributor electronic trigger assembly. This is often called a Hall effect device but this is incorrect, it is simply a rotating steel trigger wheel with 8 pips that passes closely to a coil and magnet assembly. Each time a pip passes the coil it creates a pulse that triggers the ignition amplifier that in turn activates the coil to produce the high tension feed via the king lead to the distributor cap.
1.Trigger Wheel
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2. Amplifier Pulser
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3. Timing Pointer
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4. Timing markings
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The photo 1 above shows the arrangement as can be seen the trigger wheel is very rusty also the two barrel nuts that adjust the gap between the trigger wheel pips and the coil were loose so not surprising that the spark was intermittent. The plastic spark guard cover was also broken and there was evidence of some over heating underneath around the bob weights mechanism as if the high tension had been arcing, a possibilty with the spark guard broken. The trigger wheel needed to be removed for de-rusting but was stuck solid onto the shaft. After several days of soaking in penetrating solution ( equal mix of paraffin and diesel oil) it still needed a puller to release it. So as not to stress the distributor shaft I turned up a small cylinder with its top centre drilled to fit inside the top of the distributor shaft and act as a pivot point for the two legged puller.
A new distributor with the correct plug was sourced from Motortronic but I decided to return to basics and test the entire ignition circuit from scratch. All the original components were replaced except the distributor.
Initially make sure that all the wires and connections within the ignition circuit are correct and corrosion free and that +12 volts are present at the coil +ve terminal.
The coil: Can easily be tested as follows: Remove the king lead from the distributor and connect it to spark plug with its case earthed (resting on the engine is good enough) remove the negative connections from the coil, switch the ignition on and touch the coil negative with an earthed wire, a spark should be seen at the plug every time the coil -ve terminal is earthed.
The ignition amplifier: This normally recieves a small pulse from the distributor that is amplified before pulsing the coil. First disconnect the 6.8K resistor feeding the ECU to protect it from spikes. Reconnect the negative wires to the coil. Then construct a simple pulse generator from a 1.5 volt battery in series with a 2.5K resistor (see photo 2 above). Disconnect the feed from the distributor ( 2 pin socket) and connect the socket to the battery and resistor, each time the connection is made if the amplifier is working a spark will occur at the spark plug.
The distributor pulse generator: Connect a voltmeter on low AC volts range to the 2 pin plug on the distributor, remove the distributor cap and flex the rotor arm to and fro against the tension created by the bob weights, a small deflection of a fraction of a volt should be seen on the voltmeter. If there is nothing measure the resistance across the 2 pin plug, this is conneted to the magnetic coil and should measure around 2-3 kilohms. If the coil measures OK look at the gap between the magnetic coil and the steel trigger wheel with 8 pips When a pip passes the coil centre there should be a gap of 0.2 to 0.35 mm, if not use some thin cardboard to set it accurately as a steel feeler gauge will just be attracted to the magnetic coil. If all these test are OK and the ignition is still faulty the timing should be checked.
A new distributor with the correct plug was sourced from Motortronic but I decided to return to basics and test the entire ignition circuit from scratch. All the original components were replaced except the distributor.
Initially make sure that all the wires and connections within the ignition circuit are correct and corrosion free and that +12 volts are present at the coil +ve terminal.
The coil: Can easily be tested as follows: Remove the king lead from the distributor and connect it to spark plug with its case earthed (resting on the engine is good enough) remove the negative connections from the coil, switch the ignition on and touch the coil negative with an earthed wire, a spark should be seen at the plug every time the coil -ve terminal is earthed.
The ignition amplifier: This normally recieves a small pulse from the distributor that is amplified before pulsing the coil. First disconnect the 6.8K resistor feeding the ECU to protect it from spikes. Reconnect the negative wires to the coil. Then construct a simple pulse generator from a 1.5 volt battery in series with a 2.5K resistor (see photo 2 above). Disconnect the feed from the distributor ( 2 pin socket) and connect the socket to the battery and resistor, each time the connection is made if the amplifier is working a spark will occur at the spark plug.
The distributor pulse generator: Connect a voltmeter on low AC volts range to the 2 pin plug on the distributor, remove the distributor cap and flex the rotor arm to and fro against the tension created by the bob weights, a small deflection of a fraction of a volt should be seen on the voltmeter. If there is nothing measure the resistance across the 2 pin plug, this is conneted to the magnetic coil and should measure around 2-3 kilohms. If the coil measures OK look at the gap between the magnetic coil and the steel trigger wheel with 8 pips When a pip passes the coil centre there should be a gap of 0.2 to 0.35 mm, if not use some thin cardboard to set it accurately as a steel feeler gauge will just be attracted to the magnetic coil. If all these test are OK and the ignition is still faulty the timing should be checked.