170 replies to this topic

[gaspen]

I still have some issues, any advice would be helpful

 

I've connected my multimeter to check the accuracy of the machine. As you can see it shows 56 degrees but the arc length is far from that value

 

The given dwell in the specification is for crank or cam degrees ?

 

For the light I bought cheap chinese LED's but all of them killed    It is possible that these LED's can not resists for the many on-off switching ?

 

 

 

 

Another issue that the arc lenght stretches with RPM

 

Here is two short video 

 

https://photos.app.g...Y74B6FRR7ocT9q6

 

https://photos.app.g...kqKky6ma7YwJsW6

 

[68+86auto]

Can you draw a diagram of how you have it wired up? I noticed you had an ignition coil connected. If you have an ignition coil connected it may damage some electronics.

If the LEDs are staying on for longer than required it may be because there's a capacitor in the circuit which holds enough energy for the LED to stay on.

[gaspen]

Can you draw a diagram of how you have it wired up? I noticed you had an ignition coil connected. If you have an ignition coil connected it may damage some electronics.

If the LEDs are staying on for longer than required it may be because there's a capacitor in the circuit which holds enough energy for the LED to stay on

 

 

Yes I have  the coil connected. 

 

Imagine that you have the dizzy in the car and you want to check the contatct opening with a test lamp. Mine setup is the same but the test lamp is on the edge of the rotating disc.

 

The LED has a little something on on of its leg

Edited by gaspen, 27 September 2025 - 01:04 PM.

[Spider]

I still have some issues, any advice would be helpful

 

I've connected my multimeter to check the accuracy of the machine. As you can see it shows 56 degrees but the arc length is far from that value

 

The given dwell in the specification is for crank or cam degrees ?

 

For the light I bought cheap chinese LED's but all of them killed    It is possible that these LED's can not resists for the many on-off switching ?

 

 

20250927_115904.jpg 20250927_115915.jpg

 

 

Another issue that the arc lenght stretches with RPM

 

Here is two short video 

 

https://photos.app.g...Y74B6FRR7ocT9q6

 

https://photos.app.g...kqKky6ma7YwJsW6

 

For mine, the Distributor directly switched the LED, there's no coil in circuit and I'd say, by having the coil there, that's what's causing the light to appear stretched.

[gaspen]

Thanks guys ! 

 

I ordered other type of LED's for easier installation

 

See you next time

[68+86auto]

I guess you don't have electronics stores where you are?

All that you need is a single LED and a resistor which can be calculated.

[gaspen]

I guess you don't have electronics stores where you are?

All that you need is a single LED and a resistor which can be calculated.

 

I searched locally but did not find a right one

 

First I used this simple, wired LED but the wires always broke off because they are very thin.

 

 20250921_170501.jpg   41.56K   0 downloads

 

Now I choosed this type. 

 

 902ac769-212b-44c9-adb3-f264c66b476c.jpg   33.45K   0 downloads

[gaspen]

The machine is not ready yet but it is capable for some test. 

 

1)  I've attached my multimeter in tachometer mode : it shows the rpm of the crankshaft ( 3800 rpm) and the rpm counter shows the dizzy rpm (1500 rpm) 

     I don't know which one is the correct value but it should be double / half  of each other. Next time I will connect a Smiths tachometer.

 

     Video : https://photos.app.g...RFuHBAsf58TEDn9

 

2) In this video you can hear how the 25D rattling on low rpm and as the timing jumps forward and backward. At about 800 rpm it becomes smooth as the spring starts to work - I guess

 

     https://photos.app.g...7cucFgxdkaziS7A

 

3)  The same test but with a 45D : it has more accurate timing and smooth running.

 

     https://photos.app.g...QvKPjBjfcx5EoL9

 

 

4)    Could you confirm that the spring on the far right is NOT for Lucas dizzy ? 

        

       I had this one in the 25D. The video above made with that spring in the dizzy. I replaced it with one from the left and now it also bad but in a different way

            

 

 20251005_185711.jpg   113.55K   1 downloads

 

 

 

 

 

[68+86auto]

All of those springs look correct.

Generally the earlier distributors like the 25d had weaker springs like the last one.

I can possibly record a video to show how to test the distributor issues. These are best done with the distributor in a vice.

[gaspen]

Now the deegree scale is fixed and I connected a Smiths tacho so I made some more accuratre test. 

 

Looks like my multimeter is "out of tune". This is the 2-cylinder setting, with 4-cylinder it has more error.

 

 20251007_114612.jpg   84.36K   0 downloads

 

My 45D is on the spot (1st diagram), but the 25D has a bad curve. Looks like the primary spring is too strong

 

 Screenshot_20251007_113819_Sheets.jpg   48.34K   1 downloads  Screenshot_20251007_115811_Sheets.jpg   34.84K   2 downloads

 

The video shows the 45D test. The phone records poorly, but you would see a constant 30º angle, which means a 60º dwell.

 

https://photos.app.g...KtcFVjjfPXyEQn7

 

 

[68+86auto]

How did you set it at 0?

Also note that Lucas specifications are based on a deceleration test from maximum advance. I run the distributor at a low rpm and set it at zero degrees. I then record the values for acceleration as well as deceleration. These values should be within 2° otherwise it indicates an issue with the mechanism.

[gaspen]

How did you set it at 0?

Also note that Lucas specifications are based on a deceleration test from maximum advance. I run the distributor at a low rpm and set it at zero degrees. I then record the values for acceleration as well as deceleration. These values should be within 2° otherwise it indicates an issue with the mechanism.

 

Thanks for the info. Every day I learn something new, that is the goal   

 

I set it just like you : I adjust it for the lowest rpm possible, it is ~250-300. Then I rotate the dizzy until the signal reach 0º

 

Now I have to balance the disc more, there is still some vibration.

Edited by gaspen, 08 October 2025 - 06:43 AM.

[gaspen]

All of those springs look correct.

Generally the earlier distributors like the 25d had weaker springs like the last one.

I can possibly record a video to show how to test the distributor issues. These are best done with the distributor in a vice.

 

I've  put back the weaker spring into the 25D and.....

 

 Képkivágás.JPG   53.98K   1 downloads

[68+86auto]

The noise is probably the weights since it reaches full advance. If the springs were loose zero wouldn't be zero as the distributor would've started advancing and therefore it would show up as less total advance.

[gaspen]

The noise is probably the weights since it reaches full advance. If the springs were loose zero wouldn't be zero as the distributor would've started advancing and therefore it would show up as less total advance.

 

My experience is that the weights rattle on low rpm. At full rpm they are in silent - maybe they passed out 

 

I measured the dizzy from my 1975 998. It is from MiniSpares, part number BAU1962MS. The description says it has the 41418 curve but it is a little bit different. Should I adjust it ? 

 

 Képernyőkép 2025-10-09 153906.jpg   50.83K   3 downloads