Lotus Elan

accuspark distributor no start

PostPost by: SENC » Sat Jul 04, 2020 8:04 pm

checkrail wrote:The problem is the existing yellow from the small terminal on the solenoid to the second + terminal on the coil does not show any current on the meter.

John

This would only show power when trying to crank in the #3 "start" position, not when in #2 "run", if we're speaking of the same thing, correct?

Is there a direct connection from ignition #2 to coil+?

I've seen something recently on a test to determine if there is actually a ballast resistor, since I understand they are not always in a visible place. I'll see if I can find it.
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PostPost by: EPA » Sat Jul 04, 2020 8:16 pm

I assume you are still reverted back to points (accuspark removed)
If wired correctly the supply to the + side of the coil with the ignition switched on but not trying to start the engine should read circa 6v (with the points closed) when measured between the + terminal and a good earth point such as the engine block and across the terminals of the coil. If this is not the case then then there is a supply problem to the coil. This could be the ballast resistor or any connection in the circuit including the security switch. Is the ballast resistor built into the loom and is the supply side of it accessible?
Putting a direct supply to the coil would have bypassed this circuit but putting 12v onto a 6volt coil for an extended period risks burning out the coil
If the ballast resistor is accessible then I would run a separate 12v supply to the input to the resistor (the side not going to the coil) and measure the voltage at the coil again.
If the 6v is at the coil you should be able to generate a spark from the distributor end of the HT lead coming from the coil if you disconnect it from the distributor cap and hold near the engine whilst opening and closing the points manually.
If you had a 12v coil you could just put a direct 12v supply onto the coil to bypass the other circuits.
If you can get to the point where you get a spark you can then move on to getting the timing right.
Are you sure the original problem was the ignition module?
I would bypass the security switch in any case because they can cause intermittent problems
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PostPost by: SENC » Sat Jul 04, 2020 9:54 pm

https://mossmotors.smartsupportapp.com/ ... ion-system

This thread may also be useful, with some warnings in the last post about connecting the coil to various solenoid terminals:
viewtopic.php?f=38&t=31755&start=
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PostPost by: checkrail » Sun Jul 05, 2020 8:09 am

Thanks Henry for that info. I'm going to tackle the anti-theft switch, get rid of it.

John
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PostPost by: promotor » Sun Jul 05, 2020 9:01 am

Has the Accuspark distributor been curved to the correct advance curve to match an original Lotus one? I have seen new distributors from various firms that are just generic and not correct for the specific engines despite asking sellers if they are correct and the answer being "yes". I have found the total advance to be much more than what the engine should have. I seem to remember 20 degrees distributor advance for a supposed 41189 spec distributor! I wasn't sure about the springs and weights but after finding the overall advance was too much and the quality of the parts wasn't very good I decided to fit a proper original distributor with the correct curve, and bought new springs from Distributor Doctor to make the original distributors as good as possible.

Something to bear in mind once you get up and running.
It shouldn't stop the engine starting unless it is really advanced at idle, but it may cause damage if the advance is wrong when using it on the road.

I have heard of lots of issues with the Accuspark electronic ignition modules but I have one fitted in my car (escort) and I've never had a problem apart from the initial faff of getting it timed in! Still running after 10 years or so. Maybe the failures have come from being fitted with a permanent live feed - rather than a switched feed - and have cooked them. Or, can't find where the switching point is and gave up!
Sounds like your module is OK though.
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PostPost by: checkrail » Sun Jul 05, 2020 3:08 pm

I have just bought a complete 'ready to run' electronic Accuspark distributor advertised as Lotus Twin Cam Spec.
I am on points at the moment trying to sort out the starting/timing problem, but hopefully be able to swap over to this one.
The only thing is there are no identification marks anywhere on it, I just hope that it's not a Generic Ford/Crossflow one

John
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PostPost by: l10tus » Sun Jul 05, 2020 5:03 pm

John,

Although I am not familiar with the Plus 2 wiring, only that of the 2 seater, I'll tell you what I'd do, to sort this.

Caveat:

Assuming the distributor is suitable, the carbs are ok and balanced and all the electrical and mechanical equipment is good and servicable.

I think you should ditch the balast resistor and 6v feed to the coil and use a 12v system.

Just use the points you have installed at present to get it running, then it should be a straight swap for the Accuspark system, once sorted.

I have installed the Accuspark Ignitor system and found it to be excellent and trouble free since installed many thousands of miles ago, not one issue, so I would say that if you bought the distributor as advertised, suitable for a Twincam, that it would be perfect.

Your issues lie elsewhere - probablly with the Ballast system?

The 3rd 'element' of the ignition switch which is used when cranking the engine is designed to provide 12v to the 6v rated coil, this was designed only to assist with very cold starts. (Like for exported vehicles used in Canada/ Parts of USA, etc.) - but not really for in the UK.!!

Once you let go of the ignition switch it allows the switch to spring back to the 2nd Element' or switch running position, this then powers a separate circuit and supply wire to feed the 6v coil.

There are 2no. Options here:-

First option;

Install a 12v coil with direct 12v wiring from the ignition switch direct to the 12 VOLT coil at BOTH ignition switch position 2 & position 3(cranking position). Ensuring you have a constant 12v supply in both positions as required. But make sure YOU REMOVE ANY BALLAST RESISTOR from within the wiring circuit, it's normally contained in either the form of a metal or ceramic can, or (as is the case in Rubber Bumper MGB's of similar age), a one and half meter long resistor wire, built into the wiring loom, or a resistor of another form, attached or local to the solenoid or starter.

Second option;

Retain the balast resistor system ensuring that you use a 6v or "balast resistor" type coil.

Check that the balast resistor is sound ( you need to pysically locate the balast resistor, to check it's ok, In whichever form it appears in, on your car.)

The ballast resistor is an additional piece of kit - tottally seperate from the "Ballast resistor" .coil.(Note: a coil is either 6v or 12v and does not have any form of ballast resistor built into it !)

Once you locate and establish the Ballast resistor is sound , ensure you have 6 or 7 volts emerging from the supply side of the resistor, going to the coil, when the ignition switch is in the 2nd Element or run position. This will supply the 6v current to the 6v coil for normal engine running.

Turning the ignition switch to the 3rd element or cranking position, allows 12v to supply the 6v coil only when starting, thus: (V= I / R) - providing greater current at cranking, to assist with starting in very cold conditions.

You must have one or the other options in place to start and run the engine.

Note: even if it's a Crossflow or other distributor (Not strictly designed for aTwincam) - the engine should still run smoothly and evenly, albeit not as responsive or high revving, that's all.

Good luck, keep us posted!
Philip.

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PostPost by: checkrail » Sun Jul 05, 2020 5:28 pm

Hi Philip, I have ditched the infamous anti-theft switch and am now getting 7.5v across the coil using the small terminal yellow lead from the solenoid to the coil. with the ignition switched on.
That's the first time the meter registered any current across the coil.
Tomorrow will see what happens when I try to start it.

Thanks for all you suggestions John
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PostPost by: SENC » Sun Jul 05, 2020 7:07 pm

Progress, John. How much voltage is getting to the coil when the ignition is turned to the #3/start position? That should be 12v. If that is <12v, then you have a resistance problem between the solenoid and the coil. Pictures of your wiring at the solenoid and at the coil may help, but to confirm, you have 2 wires to the coil+ (one from the solenoid and one from the ignition switch, though the latter may stop at the tach on the way)?
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PostPost by: checkrail » Mon Jul 06, 2020 4:02 pm

Another no progress day, after ditching the anti-theft switch and joining the white wires I thought things would be more promising.
I now have two wires from the solenoid to the + on the coil, one from the terminal on the left of the solenoid next to the battery lead , the other from the small terminal on the other side as previous. The meter shows 9.5v at the points to earth with the ignition on.
It doesn't want to fire up, just a couple of hiccups.

Should I not be getting 12v at the points? Looking at a photo taken when the Ignitor was fitted it has the red ignitor lead and the yellow one from the solenoid connected to + on the coil.

John
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PostPost by: SENC » Mon Jul 06, 2020 6:51 pm

John - to be sure I'm understanding what you're measuring, your current wiring is going from solenoid to positive (+) side of the coil and you're measuring 9.5v on the negative (-) side of the coil, where the distributor low tension lead is connected?

EDITED to reduce confusion.

Can you confirm you are getting spark now from the HT lead from the coil as the points open and close?

I think, if I'm following your wiring description correctly, that you have 2 wires to the positive side of the coil, both coming from the solenoid, and none from the ignition to the positive side of the coil. The impact of this, I believe, is that you are only sending current to the coil when the ignition is in postion 3, start, and not when you release the key to position 2, run. The only purpose for the solenoid to coil connection is for starting. There should be a (white, I think) wire from ignition 2 to ballast resistor to the positive side of the coil. You can run a new wire from ignition 2 to the positive side of the coil, but you'd want a 3ohm coil.
Last edited by SENC on Tue Jul 07, 2020 12:41 am, edited 1 time in total.
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PostPost by: oldelanman » Mon Jul 06, 2020 7:01 pm

Hi John,
Henry posted while I was composing my reply and I think he's absolutely correct.
Here's my two penneth...
For a ballasted coil you should have a 12 volt supply to the +ve on the coil only when the ignition switch is in the START position (ie when the starter is engaged) When not cranking ie with the switch in the RUN position, you should have around 6 volts on the other wire connected to the +ve on the coil, the 12 volt supply should then be switched off. That's assuming the battery is fully charged. I would disconnect your two wires from the coil and check the voltage on each separately as you operate the ignition switch to see what you have.

I still think, as stated previously, that your ignition timing is your main problem now. By turning the engine from TDC back to 10 deg BTDC when you fitted the points distributor and then fitting the rotor arm back in it's original position you have probably advanced the ignition significantly from where it was before. There are 11 teeth on the distributor drive gear so each tooth is about 33 deg rotation of the rotor shaft ... 66 deg crankshaft so if you are one tooth out it is unlikely to start and run. I would check the timing before you try to start it again.
Roger
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PostPost by: Craven » Mon Jul 06, 2020 7:33 pm

Remember the voltage drop introduced by the ballast resistor only happens when the contacts are closed, when the points are open no current will flow through the coil and there will be +12v on the + terminal.
Enough suggestion in the thread to confuse even the experienced.
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PostPost by: SENC » Tue Jul 07, 2020 12:07 am

I was looking for something else in an old Lucas manual and found these that may be helpful here or to others.

lucas ignition circuit.jpg and
Standard Ignition Circuit


Lucas Ballasted Ignition Circuit.jpg and
Ballasted Ignition Circuit
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PostPost by: SENC » Tue Jul 07, 2020 1:05 am

And the Lucas testing sequence for the circuit, both standard and ballasted...

LucasIgnitionTesting1.jpg and
#1


LucasIgnitionTesting2.jpg and
#2


LucasIgnitionTesting3.jpg and
#3


LucasIgnitionTesting4.jpg and
#4


LucasIgnitionTesting5.jpg and
#5
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