Lotus Elan and Lotus Elan Plus 2 Forums

Good day to everyone
I have a question for you. I have just been setting my carbs and ignition up and I have had a few issues.
The engine was running and then stopped and wouldn't start. I loosened the distributor bracket and moved the distributor and the engine fired and ran. When I went to tighten the clap the engine started to die and then picked up when I released the spanner.
The voltage to the coil when cranking the engine dropped to just over nine volts and the actual spark at the plug was pretty poor.
I have a luminition optical ignition .

Any thoughts would be greatly received.

David

over tightening the stock thin steel clamp can cause the body of the distributor to develop a crack, making it move or preventing proper setting for final tuning (not so easy to observe on the car...). There are alternate clamps to solve this issue to some extent.

Assuming everything else is fine (battery good and fully charged, earth connections clean and tight, coil known good, high voltage cables not sparking through ...), you may have to remove the distributor to check on it, after making sure this is the issue (running the car with the distributor just barely clamped, then tightening)

carrierdave wrote:Good day to everyone
I have a question for you. I have just been setting my carbs and ignition up and I have had a few issues.
The engine was running and then stopped and wouldn't start. I loosened the distributor bracket and moved the distributor and the engine fired and ran. When I went to tighten the clap the engine started to die and then picked up when I released the spanner.
The voltage to the coil when cranking the engine dropped to just over nine volts and the actual spark at the plug was pretty poor.
I have a luminition optical ignition .

Any thoughts would be greatly received.

David

Distributor should only be nipped up so it won't turn by hand. Next time you have it removed from the car check the rotor arm shaft bush play, if it's a bit worn it will do odd things like that.


The Coil voltage sounds about right, on Later cars Lotus got round this by Fitting a Ballast set up (6v coil with ballast resistor) so you can run a hot wire of the Starter Solenoid that hits the 6V coil with the reduced cranking voltage lets say 9v (makes quite a big difference to cold starting) i'd only be worried if the Voltage was anything less than 12v at the white ignition wire when it's running.

Word of warning though, make sure if you fit a Ballast set up the coil only see's Un-Ballast power on Cranking for obvious reasons you don't want 12v going to a 6v coil for too long (even though as i found out it runs really well with a Massive bright blue spark )

even though as i found out it runs really well with a Massive bright blue spark

For how long ?

John

john.p.clegg wrote:even though as i found out it runs really well with a Massive bright blue spark

For how long ?

John

maybe about an hour. A good strategy if your a sprint racer and replace the coil before each race !!!

cheers
Rohan

Mmmmmm......thinking aloud...."sport mode" switch on the dashboard by-passing the ballast resistor...?

John

From my fomative years of hot wiring Fords a ballasted coil will run the engine for some 10 minutes before overheating and misfiring, if you switch off then and leave it to cool usually no permanant damage is done but its not something to be repeated or run for longer periods.

It wont give any performance benefit either, it would ignite a leaner cruising mixture (for the 10 minutes) but at higher revs the coil will become saturated, - not the right term but its d?cades since I was involved with ignition systems.

I was half joking guys

but I did say sprint races and an hour was a top end estimate - a race more than 10 minutes and your sure risking it

It does however enable the coil to put out maximum spark at high revs when it can start to fall off especially if your limited to a conventional points ignition in your racing class. Need to probably replace the points and condenser at the same frequency as the coil after every race.

cheers
Rohan

I was half joking guys

so was I...

John

Dragging out a few long lost memories from the grey matter regarding coil saturation or whatever it was called, I think I was incorrect, the ignition current is lighter at higher RPM, if an ignition module is going to overheat and start misbehaving it will be around 2K RPM for a 4 cylinder engine.

I cant recall the specifics but there is a certain coil charging time to get the maximum spark, any longer and the output KV reduces and the coil heats up, at higher RPM it doesnt get long enough, at low RPM the dwell periods (points open) are sufficient.

john.p.clegg wrote:even though as i found out it runs really well with a Massive bright blue spark

For how long ?

John

Performance coil..... about 20 mins yep dodgy Delco ballast helped pop my Lumenition MS4 (?40 worth) my fault for assuming

Just to make it clear....... the hot wire should be run on a Ballast type Starter solenoid and ONLY over power the coil on Cranking.

Good morning all,
Thanks for all of your input, hopefully tonight I will get chance to have a look. I was thinking of adding an earth directly to the distributor from the front upright to make sure it's always earthed. Maybe a small bolt through the side casing just below the plate that holds the points.
The other thing I am considering, is to totally remove the wiring for the old immobiliser, currently I have just soldered the wires together behind the dash. Or, looking at the wiring diagram, I could take a wire from the centre fuse box, straight to the coil.

Any one carried out such a modification ?

Thanks again
David

Imho throw away all the added diy wires everywhere and go back to original. Check it out correctly with the wiring diagram. On my +2S i removed all added rubbish that was in all different colours with no logic to get it sorted correctly.
I suggest for the dissy you check to see if it is not cracked were clamp goes. There are good repair clamps available which are more solid.
Alan

carrierdave wrote:Good morning all,
Thanks for all of your input, hopefully tonight I will get chance to have a look. I was thinking of adding an earth directly to the distributor from the front upright to make sure it's always earthed. Maybe a small bolt through the side casing just below the plate that holds the points.
The other thing I am considering, is to totally remove the wiring for the old immobiliser, currently I have just soldered the wires together behind the dash. Or, looking at the wiring diagram, I could take a wire from the centre fuse box, straight to the coil.

Any one carried out such a modification ?

Thanks again
David

Well yes goes without saying if you have a suspect immobiliser it's worth getting rid (also check your Anti thief switch in the glove box, but they they tend to either work or not) if it's still there it's worth getting rid as more trouble than their worth.

As for running a power from the Fuse box.... On my Optronic Ignition I kept the white wire that goes through the Rev counter (if stock RVI Tacho) powering the coil and used the Fuse box (has to be the ignition switched side) to power the Luminition Ignition module, i found i was getting interference at the rev counter when i connected the module to the coil power as the instructions suggested.

As for grounds, i wouldn't bother running a ground to the Distributor like that (if you have a bad ground from the main engine strap the starter may use your new ground which wouldn't be good if it's lowish amp rated. You have to be very careful putting new grounds between the engine and Chassis). It's either fresh big amp cable from the battery to the Engine ground eliminating the need to use the chassis to ground the engine / Ancillary's or just clean up the main ground straps between the engine - Chassis and Battery - Chassis.

Also some thing to consider is getting your Starter rebuilt....... When my Bushes started to do i found it was drawing allot more power, on a normal day with 12.5v at the battery my coil voltage would only drop to about 11ish v but as the bushes start to go that starts to go down to the point the battery will only crank three times for 5 seconds a time before dying. Of course i don't have a huge battery on the 2 seater so it's more obvious but it's some thing else to look at.

rgh0 wrote:I was half joking guys

but I did say sprint races and an hour was a top end estimate - a race more than 10 minutes and your sure risking it

It does however enable the coil to put out maximum spark at high revs when it can start to fall off especially if your limited to a conventional points ignition in your racing class. Need to probably replace the points and condenser at the same frequency as the coil after every race.

Reminds me of my early days of employment, masquerading as an electronics tech. The "brains" of the operation (complete with electrical engineering degree) had an old Volvo that in turn had a cracked ceramic cap around the main coil wire. Worked OK if it wasn't raining, but it had been raining for about a week and the thing wouldn't start. He brought it into the lab and connected a low voltage current shorting the coil to heat it up and dry it out so he could get home later in the day.

Some minutes later, as I worked about six feet away on the other side of the bench doing actual work, a loud explosion signaled the final moment of the coil's existence. Fortunately he had the thing oriented vertically so that when the ceramic end blew off the can, it went straight up and embedded itself into the ceiling rather than, er, me. Whatever juice they pack the things with went pretty well everywhere, though, and the stink was for real and lasting.

He did, however, fail the "fix it up so it gets me home" part of the experiment. Which I suppose was a bit of poetic justice.