Oil pressure, ignition and fuel (lack of each!)!

Finally all assembled- but before I try to start it I need to check some basics. Sorry few pictures but its quite self-explanatory really.

Oil pressure: I had expected to see some pressure on cranking- obviously this will take a while after a complete refill- but even so I was dismayed to see that there was no evidence of pressure. I removed the oil pressure capillary and there was no evidence of oil movement- even worse there was no oil movement through the oil cooler hoses either! This was very worrying so I set about trying to make sure the oil pump was primed... virtually impossible to squirt oil straight into it but I did squirt more into the oil galley through the capillary attachment hole. Still nothing though. Finally I filled up the oil cooler hose and raised the full hose above oil pump height. This I think must have allowed some oil to trickle downwards into the pumps workings and this time on cranking I did detect bubbling at the capillary hole. I reattached the capillary (and all hoses) and this time the oil pressure built rather well on cranking.

Ignition
It was with great confidence that I tried to find a spark using a plug lead (plus plug) laid on the block ... to my dismay nothing! I then tried from the king lead straight to the block... again nothing!

This must mean either my connections are poor or the amplifier or coil are dodgy- possibly also the distributor but this seems to be turning alright.
When I had received the car it had no coil. I bought a used one that was believed to be from an Elite/Eclat (Ducellier) but it had no numbers- possibly this was the cause?

You all know what a coil looks like! Anyway this is the Ducellier item I mean

Anyway the constant energy system used in the Excel needs a Lucas DLB 198 coil- I did acquire an old coil from an Excel with my motor- and although this wasn't a DLB198 it was one of the types referred to as suitable for replacement by the DLB 198 (such as 45193 , 45256 , 45264 , 45267 , 45270 , 45282 , 45305 , 45310 , 45340 54041252 , 54041372). It was also marked C32 as specified in the Lotus manual and it was physically a different size to the previous coil- all pointed to the old coil maybe being wrong.
Anyway I swapped that over, carefully cleaned all contacts and treated them to some dielectric grease... and then tried again with the king lead to the block. Whoopee I obtained a nice fat and regular spark! This was good news as it must mean that my amplifier is functional too. However- when I reconnected the king lead and tried to spark at the plugs... nothing. Removing the king lead showed that the spark had now vanished there too!

This sadly became the pattern- an intermittent spark but never reliable enough to start (using temp fuel supply

Temp supply from can in boot- new filter in line

see  my "Starting: Fuel system" post). When there was a spark it was seen only at the start and end of the cranking. Frequently releasing the key resulted in a single fat spark. There was nothing during the crank itself.

A few possibilities present themselves. Since the LBPO was a bit of a cowboy (Yee-haaa!) I don't necessarily trust anything on the car - although strangely I had expected the ignition to be OK.... do I never learn?

Tatty HT leads

Anyway, looking at the HT system its clear that the HT leads were wrong. Exploring the routing used in Excels on the internet shows that the leads should be long enough to pass smoothly round the rear of the cam covers. In my case numbers 3 and 4 are too short for this route and have to fit below the inlet manifold and this suggests this set was not meant for the Excel - Despite their tatty appearance - and two leads being too short I really think these should have worked. However changing them can do no harm and might imporove matters so I bought bought and fitted a new set of Excel HT leads. There was no significant difference, my spark still came and went!

I'm working through the cheap faults first: so pursuing my distrust of the LBPO I looked at the inside of the distributor. The distributor cap appeared new, however I am still using the rotor arm that came with the car... and this looks a little odd- it has a hole in the tip! This is probably a specialised arm for something but I don't know what- I would be interested to know what the hole is for so if anyone knows please enlighten me.

Rotor arms: Original on left- new Lucas replacement on right.

As far as I can see I need a Lucas DRB104C arm- or equivalent and these don't have such a hole. I am widely warned off using the riveted sort of cheaper arm as these can crack- the metal contact must be molded into the plastic.

So I bought and fitted the new rotor arm and expectantly spun it up... sadly no change- even if there was a spark at the king lead I could still not get a reliable plug spark and it still came mainly at the start or end of a crank.

The next part on the cheap list is the cap- to be frank the cap that is fitted looks new... but as the HT leads and rotor arm were wrong who is to say that its the right cap at all!   So despite the appearance I bought a DDB108 (eq Intermotor 44750) Lucas cap. There was in fact no obvious difference between the fitted and new caps- perhaps the Lucas item was a little thicker? It was certainly a bit harder to fit.

I fitted the new cap- it was much more awkward to clip on to the distributor as it seems a little thicker. This difficulty has the ring of a correct Lotus part about it so I was hopeful. Fitting the rear clip was very difficult owing to lack of space between the cap and block. However if you get an offset screwdriver in just the right position you can slip it up behind and the clip can be "easily" fastened!... Note that I got tired of this awkwardness and did re-position the distributor later on... see below.

Using an offset screwdriver to fasten the rear distributor clip.

Well - you've guessed it: There was no difference! My spark still came and went with infuriating frequency.

Well that's the end of the cheap-ish (and virtually automatic) recommissioning replacements. I therefore started to work through the Lucas test card (No 6 for constant energy ignitions). I had put this off because intermittent faults don't really let you  work through such a test process in a systematic manner: Since I can get a spark, everything can and will pass sometimes! Anyway the process showed me the correct voltages at coil and amplifier. I obtained an increase in voltage between coil and amplifier on cranking and I got a resistance of 3.35 K ohm across the pick up coil. The card suggests that all this is indicative of a coil fault... well this is already my second coil but then I don't know that either of them are in good order, and mine can obviously give a spark on occasion. I tested the coil resistance and found it very low- 0.4 ohm between the LT terminals and 0.4 Kohm between HT output and coil positive terminal. These values are low- but not impossibly so, and I suspect owe more to the fact that this isn't a bona fide 198 coil than to any fault with it. However, although Lucas information says that this coil can be replaced by a DLB198, it doesn't actually say that  the replacement works the other way around...i.e. that my old coil can replace a DLB198.  I guess this means I have to try replacing it: A new coil is obtainable at around £10 for a non-Lucas replacement and £20 for the genuine item. Well I went for the genuine item (which hasn't yet arrived) but to be frank I don't really believe that this can be the problem and this leads me inexorably to the most expensive item: the pick up unit in the distributor!

Checking the Distributor
The coil resistance in the pick up was satisfactory, so the most likely explanation for all of my problems is an intermittent connection somewhere- and the usual culprit for this is the wire between AB14 and distributor. In particular the section between the WM12 plug union and distributor which often breaks as it passes through the plastic grommet into the distributor body. Of course I had suspected a loose connection/broken wire earlier but I was unable to cause the spark to come and go by moving any of the wires... however a break such as this where the wire is "held" by the distributor might explain that.

A new pickup is by far the most expensive part of this system and at around £60 its second only to a new distributor! However, if it is simply  a broken wire (and the coil resistance does look OK) then perhaps I can recoup some cash by fixing it with a new piece of wire! However, this isn't ordinary wire- its silicone coated which I think is very flexible, meaning it can be bent without resistance so its doesn't build up a spring-like tension.

In order to check this you have to remove the distributor. My timing is only set approximately by the static method; even so I didn't want to upset it so ...

Scribe paint or draw a line from distributor body, across the bracket and onto the aux housing

Loosen the bracket retaining bolt...NOT the clamp bolt

Withdraw the distributor with clamp attached - nice to see evidence of oil here- and the fact that my new O ring has been sealing it!

The distributor can then be  removed - note the new rotor arm and flash shield. All my stuff looks pretty even if it doesn't work!

Flash shield fits over input grommet at this cutout.

 Inside, the wires feed into the pickup coil through a plastic shield or guide. This is only attached by one screw and taking it out doesn't affect pickup spacing.

Plastic wire guide inside distributor- mounting screw top

Guide removed and wires released

The usual test for a break in a silicone wire is to try and gently stretch it... the coating is flexible and stretchy so if there's no continuity in the wire the coat will extend... I tried the stretch test but to be frank it wasn't conclusive- there is an innate amount of "stretchyness" caused by the fact that these wires have been bent for so long. However if there is a break that stops my spark then my guess is that it must be complete. There is no terminal to test the wires alone as they are molded into the pickup, but by reattaching the AB14 lead I could insert a couple of probes and measure the resistance of the pick up coil again.

Out of focus.. but attach probes at the AB14 lead terminals

... and measure resistance

I expected that any break would show a switch to open circuit or at least a fluctuating reading as the wires are stretched. In fact I obtained a rock steady resistance that wasn't altered by attempted stretching of either/both of the wires at any point. I have to conclude that, tempting as it is as an explanation, there is no evidence for wire breakage here. If there is a pickup fault then its more subtle than a broken wire. I will have to hope that the new coil will fix it otherwise I think I am looking at a new pick up.

Fiddling: Timing/Distributor position
Timing should have no effect on sparking- I should still get a spark as the reluctor turns and in fact, the distributor cap isn't necessary for this at all. I had set up the timing a while ago using the static method and at that time I located the compression stroke on cylinder no 1 using a cork to plug the sparking plug hole. This popped out as the piston started to rise on the compression and I could then just turn the motor forward to 10 deg BTDC. In this position the rotor arm is angled at 45 degrees with the rotor arm itself  pointing downwards and inwards towards the motor, In this position the distributor clips were really awkwardly positioned and very difficult  for fastening/unfastening; also the plastic grommet where the silicone wires entered the distributor was jammed very close up against the block- where it obviously runs the risk of getting too hot if the motor ever fires! I reasoned that the distributor can be turned freely around the rotor arm shaft  as one reluctor point is pretty much the same as any other. I decided to set it in a better position. I set the motor into the timing position, removed the distributor cap and loosened the clamp bolt. I could then rotate the distributor around the shaft and align the pick-up on another point of the reluctor. I could then refit the distributor cap and rearrange the HT leads so that this once more correlated with no 1 cylinder at the bottom diagonally and gave the firing order 1342 in an anticlockwise direction (as seen facing the rotor arm from the driving seat). Access was now easier and  the silicone wires entered the distributor more freely.

The AB14 Amplifier
The fact that I can get a spark, and that voltage at the coil increases on cranking suggests that the AB14 is working- of course this again hits the "intermittent fault" proviso above.

It is important of course to eliminate simple problems and I have checked that this box is earthed to the motor... and it is, and there is no significant voltage between box and earth as in the Lucas test card procedure. The wiring diagram suggests an earth wire should originate inside the box at a terminal on the amplifier module but I can find no such wire.  Instead it seems that the box is earthed via a black cable ring connector that attaches to the top under the braided contact that earths the shielding in the AB14/Distributor lead. As a confirmation I ran a second earth lead directly to the chassis and confirmed that this gave no effect on the presence or absence of a spark whether it was connected or not.

Luckily I do have two AB14s- one that was fitted to the car when I got it and a second that came with the spare motor. I have already described this one which I think is in good order but as both are used, I don't have an absolute guarantee that either of them actually works! Anyway, swapping the units and leads gave no discernible difference in behaviour. I fitted new terminals to one of the AB14-to-Distributor leads and this also had no effect. Finally, I obtained a replacement amplifier unit (Intermotor part 15210) and swapped this over inside the AB14- again there was no discernible improvement and to be frank it looked like the spark had now vanished!  I'm not convinced the Intermotor part is very good quality, but its possible I haven't fitted it properly so I swaped it back to test some more.

Fitting the Intermotor amplifier. I covered 1/3 of the base with heat conduction compound.

My coil swap seems to have intensified the spark when it is present, but hasn't done anything for the sporadic nature of the thing. Perhaps distributor output to the amplifier is itself sporadic or absent? I was able to attach a Voltmeter across the distributor lead and showed a voltage output as the motor is turned. As my meter is digital it tends to fluctuate anyway but it seemed that there were separate pulses and all about 1.5 mV in size- however I was measuring DC and the output I now realise is AC. A Jag V12 should give an output (same pickup) of 0.3- 1.5V AC- I guess this might be lower for a 4 cylinder motor especially one with a low cranking speed so I will test again and measure AC when the distributor is refitted.

 I am running out of things to try!

Next day I worked through the Lucas test card again with no real problems identified... so it must be working then huh? Well no not really! One comment from the forum where a similar spark pattern had been observed...(sparking at end of the crank when the key is released but not during cranking), was been attributed to a defective ignition switch. The Lucas method doesn't even mention the switch but I guess its to be suspected if everything checks out- and that's the position in which I now find myself! Accordingly I decided to strip the switch and investigate further. If the fault lies there then it probably means, that none of my mucking about in the ignition system was really necessary; but at least I know it has done no harm and new HT system will probably help a little!

This entry has already become an unwieldy length so I will deal with the switch in a separate posting.