Luminetion Ignition

[lwasson]

Hi All

Was getting the '83 Turbo ready to travel for the Rolex 250 Cam Am race at Barber Motorsports in Birmingham, AL USA when she would not fire on cranking. Heart broken I traveled to the race in another car.

Yesterday, I finally got time to look at it the ignition and there is no spark at the plugs or coil. I replace the coil with another to test but still no spark.

Luminetion testing procedure from manual says to pull the HT lead at the dizzy, remove the cap. Turn ignition on and block the LED beam at the dizzy and this will produce a spark from the HT lead. It did so the over all Luminetion should be working?

Further test showed I am getting 2.67 volts at the black and blue wires going to the dizzy from the Luminetion amplifier This is spot on. But when I blocked the LED beam I got no voltage drop from the blue and black wires (suppossed to drop to 1.8v). Another test is to jumper the blue and black wires going to the dizzy and this will produce a spark from the HT. Did this and got no spark from the HT.

My question is why does the first test show the over all Luminetion system working correctly but the other test indicate the amplifier may be bad? Am I testing the ignition system correctly?

I see from other posts that some have replaced their Luminetion system. Any good recommendations if I decide to make a change?

The car has been reliable for over a year. I keep forgetting that some components on the car are almost 25 years old. I guess the Luminetion's time may have come.

Thanks!

Louis

'83 Turbo

[WayneB]

I think the trigger eye has gone bad. I used to have this problem with some of my racecars that I was using this ignition on.

I dont think the Optical trigger is sold separatley either ATM (unless you get lucky and find one somewheres)

Even If it isnt the Eye, but turns out to be the spark box , its resin sealed so you cant get in to repair it.

All you can do is check all the wires have continuity and you have a good ground.

If I were you, I would convert it to a magnetic triggered system (Crane /Pertronics or a Lucas constant energy setup If you want a period correct setup)

Edited July 27, 2007 by WayneB

[lwasson]

Thanks Wayne for the info and replacement suggestions.

We're going to go thru everything again tonight. Got an extra hand to to make testing a little easier and make sure I'm doing the test correctly.

You say the LED eye is out. What confuses me is one test says the eye is sensing the infrared light (block eye HT lead sparks) but the other test measured at the blue and black wires from Luminetion box says it doesn't work (voltage does not drop from 2.67v to 1.8v).

Will go thru it again to make sure I'm doing it right.

Louis

'83 Turbo

[molemot]

Lumenition sealed boxes are phenomenally reliable...mine withstood being underwater for months...often, the problem is the connector between the distributor and the spark box - where you have been making your measurements. The contacts get dirty and are a swine to clean without removing them from their plastic holders - this involves carefully pushing flat their retaining spikes. It's the only place I've ever had ignition related problems in 20 years of ownership..I even thought that the sensor unit was dead and bought a new one...but the problem turned out to be the rotten connector! If you get a good spark when you break the lightbeam from the led to the phototransistor, I reckon the engine should run.

[cly_mitchell]

Louis,

I replaced my Lucas ignition with the Pertronix ignition. You can swap the ignition and coil for about $130.00. It is very easy to install. Call JAE, they have them in stock.

Cheers,

Clay

[USAndretti42]

I got a new photocell for my Luminention from JAE a while back when a wire broke. I was less than $20. (Too lazy to dig out the receipt to check the price.) I would give JAE a call to see if they have them still before spending $130 on a new system.

[lwasson]

Thanks All

The system is shot. Holding the coil lead to ground it began to fire randomly even if the optical eye was blocked or not. So I'm going to get a Petronix from JAE for $114.

For kicks we decided to look into the control box. It was completely filled with a resin like soft rubber. I can understand how it would still work even after being underwater as Molemot mentioned. I guess the resin is to keep out moisture and prevent vibration. Anyway, we dug all the resin out and its just a simple circuit board with what I would call controller chip mounted to the board.

Louis

'83 Turbo

[lwasson]

Just in case anyone is curious about what's inside the Luminetion control box see the attached pic. I couple of resistors and diodes and a control chip. With the distributor out of the car waiting to be fitted with the Petronix system we hooked up a battery, coil and the Luminetion system back up to the distributor and the coil still would not fire. We also made sure all the connectors were clean and fitted tight together.

The chip could be crossed referenced at Radio Shack and a new one installed. It might be good to have a backup ignition system.

Louis

'83 Turbo

[hilly]

Just looked up that device, it is a BU931 high voltage darlington transistor designed for ignition applications.

From what I can see from the photo there isn't anything on the PCB that is too complex (2 SOT23 devices probably transistors, 2 diodes, a capacitor, maybe more on the other side I cna't see) so getting it going again should be possible.

RS have got them in stock (part No 313-3197) at

[molemot]

Agree with Hilly..the BU931 is the most likely thing to fail, but there isn't much on the board and even the surface mount stuff should be readily changeable..that's the thing with encapsulation, hides a multitude of whatevers. I used to work for an electronics company in Molesey - not a million miles from Hilly! - and they were making encapsulated devices for the aerospace market. They'd sold lots to Aerospatial for the Airbus...trouble was, they didn't work. So, the first batch shipped was just a plastic box full of encapsulating rubber with the connecting pins coming out the bottom...and nothing else inside!! It took months before any were installed at Toulouse...of course, they didn't work...opening them up invalidated the guarantee, so they all came back...by which time we'd made the design work, so we could ship them back by return!!!

[lwasson]

Thanks Hilly

There is nothing on the other side of the board. It is covered with a paper thin, smooth flat material so the board can be glued to the aluminum block for heat transfer.

I will go to Radio Shack and pick the transitor and see if we can make this thing work.

Great story too Molemot.

Louis

'83 Turbo

[iainskea]

Interesting read this post - as I have a disconnected luminetion brick and 'eye' in a spare box, with my car de-modified back to standard dissy (when I bought it).

On the sealed unit ideas - water prevention is most likely the reason for the resin, but a lot of units like this are resin filled to protect the IP (intellectual property) - a was amazed you could clean it up enough to get a look at the amp number. Good effort!

Our technicians actually have to X-ray multilayer circuit boards to find faults before digging into grey-coloured resin to find the component.

I know the pertronics is the way to go, and I will be grabbing a unit shortly. Not sure what I have to do with the dissy though - do I need a new dissy?

Iain

[cly_mitchell]

No mate, you just gut it and put in the pertronix unit. The only thing about the pertronix ignition is it uses your advance machanics. So they need to be in good working order. Easy install.

Cheers

Clay

[dglotusltd]

Sounds like you may have switched dizzys. You need to know exactly what dizzy you are using to get the Pertronix kit. My S1 had its original 23D switched out to a 45D4 without a vaccum module when the PO converted it to euro spec. So there is a specific kit for each of the Lucas dizzys used in the various Lotus cars.

DomG

[iainskea]

Sounds like you may have switched dizzys. You need to know exactly what dizzy you are using to get the Pertronix kit. My S1 had its original 23D switched out to a 45D4 without a vaccum module when the PO converted it to euro spec. So there is a specific kit for each of the Lucas dizzys used in the various Lotus cars.

DomG

Yup Dom, I thought so - mine is a 45D (something) - I will check.

Thanks,

Iain

[dglotusltd]

The 45D4 Dizzy i have took a Pertronix kit LU143. first glance showed it was the wrong kit as it seemed impossible to fit.

Had to take the dizzy out and hold it in my hands to see the truth. Its just that the assembly where the sensor it sits almost 180 degrees opposite where the optical sensor sat for the Lumination.

Take the dizzy out and read the designation off the side and THEN order the kit accordingly. I actually returned the kit and the guy where I bought it let me take a few other back home. After about an hoour i finally realized the original kit was the correct one. Da!

DomG

[lwasson]

I got my Pertronix LU-147 ignition but it will not fit. I have a 41953 B 45DM4 distributor. I'm wondering if the plate (I call it the points plate) in the dizzy has been changed by a PO? I've contacted Pertronix and JAE and sent the attached photos of the points plate to see if it had been changed. JAE didn't have a dizzy for comparison and Pertronix hasn't gotten back with me.

Can someone tell me from the picture if my points plate is correct? If it is I will have to drill some new holes in the LU-147 mount plate to mate with my points plate.

Thank you,

Louis

'83 Turbo

[dglotusltd]

oops. I have a 43d4 which is the LU143. The 45dm4 is the mate for the LU147 you got.

So I cannot say if the plate you have has been modified. Yikes!

If you have to drill then there is no telling how to position the sensor assembly so as to have the car timed properly. At the least it will not be easy.

Best bet is to try to look at a real 45dm4. That would be a 77 to 81 triumph spitfire. In the Pertronix documents the Lotus cars used a 43d4 like mine in Eruo spec. The Pertronix list only shows Lotus cars up to 79.

Not much help...sorry

Per the Pertronix site

Lucas

43D4 / 45D4 ....................................... 4 CCW 45 LU-143 9LU-143

43D4 / 45D4 ...................... ............ 4 CCW 46 LU-144 9LU-144

45DE4, 47DE4 .................................... 4 CCW 2 LU-141 9LU-141

45DM4 & 47DM4 ................................. 4 CCW 2 LU-147

Footnotes:

2 Factory electronic ignition

45 With red fixed points

46 With blue sliding points

Sure its a DM?

[lwasson]

oops. I have a 43d4 which is the LU143. The 45dm4 is the mate for the LU147 you got.

So I cannot say if the plate you have has been modified. Yikes!

If you have to drill then there is no telling how to position the sensor assembly so as to have the car timed properly. At the least it will not be easy.

Best bet is to try to look at a real 45dm4. That would be a 77 to 81 triumph spitfire. In the Pertronix documents the Lotus cars used a 43d4 like mine in Eruo spec. The Pertronix list only shows Lotus cars up to 79.

Not much help...sorry

Per the Pertronix site

Lucas

43D4 / 45D4 ....................................... 4 CCW 45 LU-143 9LU-143

43D4 / 45D4 ...................... ............ 4 CCW 46 LU-144 9LU-144

45DE4, 47DE4 .................................... 4 CCW 2 LU-141 9LU-141

45DM4 & 47DM4 ................................. 4 CCW 2 LU-147

Footnotes:

2 Factory electronic ignition

45 With red fixed points

46 With blue sliding points

Sure its a DM?

Thanks Dom

I'll see if I can come across a 45DM4 for comparison. A friend has a Spitfire but not sure on the year.

Louis

'83 Turbo

I just got a call from Pertronix and they said the points plate on my 45DM4 is not stock. I wonder when a PO put in the Luminetion system the kit came with a new plate to mount the Luminetion optical eye?

Off to find an original points plate for my dizzy.

Louis

'83 Turbo