No Spark Gremlins

[MetBlue]

Gremlin is still with me - Or at least it was last Thursday.
Cars not been used much last few weeks and the battery was low, both just enough to get the fire going. 3 miles later, Engine died. Side of road investigation showed yet again no sparks.
Fitted new dizzy cap and rotor, plus recharge of battery, and off we go again. - First known time though where the spark disappeared mid journey.
Further investigation yesterday before refitting the air box identified another potential cause - How many time now have I thought that ?
The main HT lead between coil and Distributor had rubbed against the hex screw of jubilee clip holding the crank shaft breather. Wasn't rubbed through, but definitely thinning the insulation.
The other end of the lead had a secondary black rubber sleeve, which to my mind was the wrong end.
So sleeve persuaded to slide down to teh Dizzy end and jubilee clip re positioned and we'll wait on now and see if problem repeats.



Above photo taken after the secondary sleeve was repositioned, but before I turned the clip over.

Certainly stacks up with the Winterbottom event, when I removed the coil end of the HT lead and plugged in a spare to check spark. Unplugging will hav emoved the lead away from the potential earth path.

[MetBlue]

I thought ( hoped) this thread was dead, but allas no.
I've done best part of 800 miles since last incident with no issues at all. Things were really looking up and confidence was growing, then last Friday when departing for LITP, drove about 4 miles, then lost sparks ( Spark tester inserted and nothing).
After 10 minutes and removing a plug or two to dry, and we're off again. 2 miles later- Again no spark. Did nothing, just sat for 10 minutes and away we went. then repeated again 1 mile later. Time to abort ideas of getting to LITP in a Lotus
A kind gent across town offered his drive for the weekend. Returned last night to pick up. Fired instantly and drove 6 miles home without missing a beat.

Starting when cold has been absolutely fine since I turned the jubilee clip so I'm now convinced looking back I've had two different intermittent faults. ( Stone cold no spark and No spark after a few miles).

Although a change of coil has been tried for the COLD start problem ( made no difference), maybe it could be my hot stop issue, so today i'll be ordering a spare. I'll also be taking the distributor out and having a good look at the pick up, as well as trying my best to check the integrity of the wires in the circuit and the few remaining connections I've not yet remade. - SOOOO frustrating.

- Might also put some Willow branches in the boot, so if it dares do it again I can do the Basil Fawlty "right you B******, you've been warned" dance.

Tony

[Hawaiis0]

Have you checked for PO splice repairs in the coil feeds?

[MetBlue]

Another discovery and a line of thinking that adds up, but is this just another false dawn?

Removed the distributor and stripped the top end down. First discovery was a broken up Nylon castellated drive for the magnetic rotor. Won't have been my problems, but could have caused big issues if any of the smaller bits had fallen into the mechanical advance mechanism. Much to my surprise they still seem to be available as a spare part.
Test meter across the pick up coil and got around 2500 ohms, which seems about right, wriggle the wires around and resistance starts to wander around, then goes open circuit.
Much fiddling later ( and removal of the rubber sealing grommet, so don't comment such on the photo below) and I conclude that if EITHER of the wires at the 90 deg turn before exiting the distributor are straightened, it goes open circuit. EUREKA - Could this finally be it.


Then the penny drops. Could this be why the vac advance was disconnected? These wires will only move around significantly when the vac advance comes in.
_ And typically I reconnected the vacuum after months of trouble free running without it, only a few miles before the this last episode started.
Moral " If it ain't broke, don't fix it just before a significant run out".

Now just waiting for the new parts to come through,

Fingers crossed.

[Pete Boole]

Sounds like you might have found the culprit! Fingers crossed for you

Pete

[Tanz]

When we were chatting at LITP I mentioned I had a wire break through fatigue due to the constant back and forwards of the vacuum advance movement. Mine actually broke the wire so was easier to find the fault.


This was an Aldon unit. I bought another Aldon unit to replace it and it had thicker wires. Guess they must have had a problem with a few units and improved them.
Worth checking from time to time to see if the wire is starting to break

It sounds like you have sorted it Tony - great news!

[Marten]

I bought another Aldon unit to replace it and it had thicker wires. Guess they must have had a problem with a few units and improved them.

Making a wire thicker is the opposite of making it more flexible to whitstand repeated bending. The usuall way is more but thinner strands . So I hope they changed more than just the wire gauge

[Lotus-e-Clan]

I bought another Aldon unit to replace it and it had thicker wires. Guess they must have had a problem with a few units and improved them.

Making a wire thicker is the opposite of making it more flexible to whitstand repeated bending. The usuall way is more but thinner strands . So I hope they changed more than just the wire gauge

Same principle for Elite clutch cables which wrap tightly around a small diameter pulley. I had two Christopher Neil cables break in quick succession because the strands were too thick and low in number. Solved the problem with a high number, thin-stranded cable.

[richardw]

Many strands make lights work.

(Sorry!)

Richard

[MetBlue]

. (Sorry!)

I should think so

[AndrewWebber]

The 'wire' fracture issue can also happen on 'points / condenser' ignition. Driving the Elite around Belgium, suffered sudden complete engine shutdown, no spark. An hour later of road side diagnostics, most which was the time to remove the air box so I could see the dizzy, found the back wire inside the dizzy going to the points had 'fallen in two'....Maybe the '900' engine has a nasty frequency vibration somewhere in the rev range.... The wire was probably 43+ years / 154000 miles old mind you.

[bash]

Have you tried direct wiring the coil because when mine ftp it was a break in the loom.

Bash

[MetBlue]

Been on quite a journey since the weekend - not of the mileage kind - more of the emotional rollercoaster kind.

Collected a new Distributor pick up coil on Saturday, which checked out at a solid 3140 Ohms. Far steadier and stable than the 2400 I saw fluctuating on the old pick up and no complete drop off when bending the wires. I did need to space it up by a washer from the base plate because without, the coil touched the base plate, locking the Vac advance turn ( just a watch out if anyone else fits a replacement).
On fitting the rotor arm, noticed the centre top was badly burnt / blackened. Checking the inside of the distributor showed the central sprung carbon peg was either broken or jammed up inside the cap, with much sign of arcing. Quite surprised the car would even run, but in hind sight, this could be the real reason it kept stopping after a mile or so. Hadn't got a new cap handy, so used the one I removed last August.
Completed the rebuild expecting an immediate start and ----- No spark !!!
Swapped the Ignition coil for the new Viper one I bought last week and we have a result. Fired instantly.

Went off for a test drive and all I can say is WOW. A completely different car. Instant response to the loud pedal and a very decent level of power below 3000, which I hadn't experience before. And no hesitation / stutter on the pick up, even when cold. I noticed when I got home the tick over was now at least 200 RPM more, but that's an easy fix. - One very happy punter.

So this morning, out their with the lark for an early morning run and ....... Won't start !!!! Didn't have time to investigate so took the other car, but over the morning it did dawn on me that the change of distributor cap last August coincided with the time the "first thing in the morning no start" went away.

Picked up a new cap from local motor factor on the way home, fitted and were running again - and driving power like it was yesterday

So we now have a new distributor pick up coil, new Ignition coil and new Dizzy cap. Along the way, I've also confirmed my spare AB14 is good ( at least the engine started) so surely this must be fixed now - Until tomorrow

Been a long road, but are we finally there?

Tony

[TAR]

Fingers crossed for your morning start up

[Pete Boole]

Well done on (hopefully) getting to the bottom of it!

Pete