35 replies to this topic

[gaspen]

Cheers for that. I asked so I could look up what the specs were for a similar Lucas unit.  It is as I guessed earlier;-

 

0 - 800 RPM    No Advance

900 RPM         1⁰

1500 RPM        8⁰

2400 RPM        11⁰

4000 RPM        16⁰

 

I have looked a little deeper in to these numbers to be certain and they are Crankshaft RPMs and Angles.

 

The Vacuum Advance starts at 6" Hg and finishes at 14" Hg where it gives 16⁰

Unless you have a small hand Vacuum Pump and a Vacuum Gauge, it's not really practical to test the Vacuum Advance Unit. As it doesn't really impact on the engine's performance, I wouldn't worry too much about testing it for where it starts and finishes, but that it does provide advance when vacuum is applied and that it doesn't leak. The other RPM related numbers are on the mechanical centrifugal advance unit and these you can test with your dial back strobe. Check them with the Vacuum disconnected.

The centrifugal numbers are actually measured on a decelerating speed, so, start at say 4300 RPM (a higher speed than where it gives full advance) and work back from that.

 

Thanks Moke !

 

Which Lucas dizzy has these values ? Is there a chart for all the Lucas dizzys ?

[Spider]

 

Cheers for that. I asked so I could look up what the specs were for a similar Lucas unit.  It is as I guessed earlier;-

 

0 - 800 RPM    No Advance

900 RPM         1⁰

1500 RPM        8⁰

2400 RPM        11⁰

4000 RPM        16⁰

 

I have looked a little deeper in to these numbers to be certain and they are Crankshaft RPMs and Angles.

 

The Vacuum Advance starts at 6" Hg and finishes at 14" Hg where it gives 16⁰

Unless you have a small hand Vacuum Pump and a Vacuum Gauge, it's not really practical to test the Vacuum Advance Unit. As it doesn't really impact on the engine's performance, I wouldn't worry too much about testing it for where it starts and finishes, but that it does provide advance when vacuum is applied and that it doesn't leak. The other RPM related numbers are on the mechanical centrifugal advance unit and these you can test with your dial back strobe. Check them with the Vacuum disconnected.

The centrifugal numbers are actually measured on a decelerating speed, so, start at say 4300 RPM (a higher speed than where it gives full advance) and work back from that.

 

Thanks Moke !

 

Which Lucas dizzy has these values ? Is there a chart for all the Lucas dizzys ?

 

 

That one is a Lucas 45D4 Serial Number 41418. Rather common and fairly easy to come by.

If you are considering going to a Lucas unit, I can recommend these;-

https://www.minispar...|Back to search

 

Unlike all the others I have tested, these are actually on spec. You can order them with the electronic type points too.

[gaspen]

To be honest I have an old 41418 for spare with new springs and points but I'd like to keep the "originality". On the other hand we never know what they had on stock at the time of manufacture. Two years ago I bought a spare Authi engine from Croatia and it has a Lucas 25D (but it is incomplete)

 

Anyway I give a chance for Femsa.

 

I'll keep you updated 

[gaspen]

 

 

Cheers for that. I asked so I could look up what the specs were for a similar Lucas unit.  It is as I guessed earlier;-

 

0 - 800 RPM    No Advance

900 RPM         1⁰

1500 RPM        8⁰

2400 RPM        11⁰

4000 RPM        16⁰

 

I have looked a little deeper in to these numbers to be certain and they are Crankshaft RPMs and Angles.

 

The Vacuum Advance starts at 6" Hg and finishes at 14" Hg where it gives 16⁰

Unless you have a small hand Vacuum Pump and a Vacuum Gauge, it's not really practical to test the Vacuum Advance Unit. As it doesn't really impact on the engine's performance, I wouldn't worry too much about testing it for where it starts and finishes, but that it does provide advance when vacuum is applied and that it doesn't leak. The other RPM related numbers are on the mechanical centrifugal advance unit and these you can test with your dial back strobe. Check them with the Vacuum disconnected.

The centrifugal numbers are actually measured on a decelerating speed, so, start at say 4300 RPM (a higher speed than where it gives full advance) and work back from that.

 

Thanks Moke !

 

Which Lucas dizzy has these values ? Is there a chart for all the Lucas dizzys ?

 

 

That one is a Lucas 45D4 Serial Number 41418. Rather common and fairly easy to come by.

If you are considering going to a Lucas unit, I can recommend these;-

https://www.minispar...|Back to search

 

Unlike all the others I have tested, these are actually on spec. You can order them with the electronic type points too.

 

 

Well it is not what I expected. On the left is your data, the two on the right are my values. I should go for an electronic before I am going crazy 

 

(Please do not take into account the text "41418" and "41412")

 

 Képkivágás.JPG   23.79K   2 downloads

Edited by gaspen, 28 September 2021 - 01:27 PM.

[gaspen]

A stupid question : is your data that I have to measure on my crank OR are these numbers ABOVE the initial (idle) setting ?

 

0 - 800 RPM    No Advance

900 RPM         1⁰

1500 RPM        8⁰

2400 RPM        11⁰

4000 RPM        16⁰

[gaspen]

And look the new secondary spring. It is loose even with the weights fully out.

 

 IMG_20210928_100359.jpg   42.06K   1 downloads

[Spider]

A stupid question : is your data that I have to measure on my crank OR are these numbers ABOVE the initial (idle) setting ?

 

0 - 800 RPM    No Advance

900 RPM         1⁰

1500 RPM        8⁰

2400 RPM        11⁰

4000 RPM        16⁰

 

Yes, you will need to add to these figures any static setting of the distributor. From memory I think I saw a figure of 7⁰ for this static setting, so the 0 - 800 RPM number you'd see with your dial back light would be 7⁰ and the 900 RPM 8⁰ and so on.

[Spider]

And look the new secondary spring. It is loose even with the weights fully out.

 

Well,,,,,,,, that explains the shape of your plots !

 

I see too the bob-weight has the number 11 stamped in it. That's the total amount of advance the weights will give before hitting the stops, this number however is in distributor degrees. It should be an 8⁰ set. I'd say it's been messed with previously.
 

[gaspen]

 

And look the new secondary spring. It is loose even with the weights fully out.

 

Well,,,,,,,, that explains the shape of your plots !

 

I see too the bob-weight has the number 11 stamped in it. That's the total amount of advance the weights will give before hitting the stops, this number however is in distributor degrees. It should be an 8⁰ set. I'd say it's been messed with previously.
 

 

 

Now I understand why Femsa won't fit perfectly to this engine : It adds 16° advance >> 32° on crank. My initial timing should be 0° or less ?!  

 

Lucas 41418  adds 11° >> 22° on crank. It seems much better to my eyes 

[Spider]

The Femsa does seem rather odd for your engine, to me.

 

With the static timing set to 0⁰ or 'less', you'd likely find the engine hard to start, particularly when cold.

 

You do seem to have a handle on advance curves etc, you may also find this of some general interest;-

 

https://www.theminif...d-distributors/

 

[gaspen]

The Femsa does seem rather odd for your engine, to me.

 

With the static timing set to 0⁰ or 'less', you'd likely find the engine hard to start, particularly when cold.

 

You do seem to have a handle on advance curves etc, you may also find this of some general interest;-

 

https://www.theminif...d-distributors/

 

Yes I found that topic already. That is one reason why I want to achieve a good curve.

 

Someone says : "don't deal with it, if the car runs, do not repair it"

 

But I spent lot's of money and time to this car, I'd like keep in a good working order.

 

I think the comfortable option is a 45D with electronic "points", a BAU1962MS I guess. Isn't it ?

[Spider]

That's the distributor.

Nice to find out that the FAQ's are read by members

 

Someone says : "don't deal with it, if the car runs, do not repair it"

 

I prefer to maintain them than wait for them to break.

[gaspen]

That's the distributor.

Nice to find out that the FAQ's are read by members

 

Someone says : "don't deal with it, if the car runs, do not repair it"

 

I prefer to maintain them than wait for them to break.

 

Agreed. Ordered the dizzy today, I hope I get it next week.

 

Thanks for your support, Moke.

[gaspen]

That's the distributor.

Nice to find out that the FAQ's are read by members

 

Someone says : "don't deal with it, if the car runs, do not repair it"

 

I prefer to maintain them than wait for them to break.

 

 

The new dizzy - BAU1962MS-  arrived today and I installed it immediately     Also I purchased a new Bosch Blue coil. I set the initial timing to 8° at 1000rpm. The Mini starts easily and runs flawless.

 

After a short test drive I made some quick measurements

 

Without vac it gives 22° advance at 2000rpm. Seems more than needed ?

 

Dwell is ~27% (yes my strobe measure in percent). Is it specific for the electronic dizzy ?

[Spider]

Great news - sounds like it's chalk and cheese ?

 

The amount of advance sounds about right. I should have mentioned in the numbers I gave above, those are the originals from the days of leaded petrol. Mini Spares apparently have them tweaked a little to better suit unleaded fuels, so there'll possibly be a degree or 2 difference here and there in the curve from those numbers. The distributors I've tested in their range have been for 1275 engines and they track bang on to the original curves, others might have some variation as mentioned.

Proof of the pudding as the say, is in the eating. If the engine does everything it should - starts on the button, drives without pinking, temps stay in the right range, cruises smooth, accelerates as you would expect - then you can be reasonably sure, at worst, that it's close to the mark and likely to get any better would involve a rolling road session and the dissy tweaked from that.

 

In regards to your dwell angle I've never looked in to that nor measured that for these with the Electronic modules - not much you can do about it anyway, however, as they switch 'clean' they will need less. When I say switch 'clean', if you were to look at how points switched on an oscilloscope, you'd notice as they open and close, the current doesn't snap from off to on and on to off, but there's some 'fuzz' or 'noise' at these occurrences, where as the electronic module does snap open and closed clean. By doing so, it needs less dwell and even with the same coil, you'd find that when running from the electronic module, it'll have a higher output voltage as a result of this clean switching.