• Hi Guest!
    You can help ensure that British Car Forum (BCF) continues to provide a great place to engage in the British car hobby! If you find BCF a beneficial community, please consider supporting our efforts with a subscription.
    There are some perks with a member upgrade!
    **Upgrade Now**
    (PS: Subscribers don't see this gawd-aweful banner
Tips
Tips

123 Ignition vs. Mallory

Share this page

Re: 123 Ignition vs. Mallory--modernized Lucas alt

The switch to adjust the advance curve on the 123 is more convenient no doubt. Mallory does sell an advance curve kit though that may be more flexible. One kit I saw had 9 springs (4 pair and a single) plus 8 keys to change total advance.
 
Re: high speed detonation

Steve G,

In answering your questions, rather than pulling out my old textbooks and other info and collating the data for you, I just did a quick google on preignition vs. detonation. You might do the same. I encountered a preignition failure on one of the Formula III engines that I had to replace the head gasket on, waiting at a Spanish border crossing to get down into Portugal for an event. We didn't have a proper timing light so I just reset the rotor to where it had been, via scratch marks. The piston edges were burnt down to the ring. I saved one of the pistons as a memento to not do any repairs if you do not have the proper tools, needed for a critical operation.

https://yarchive.net/car/knock.html

this is just one of the sites pulled off the google search, many more that expalin in detail.

hth
 
Re: high speed detonation

Hi Greg et all,

inspired thru Greg's comment on the octane rating I did some more research on the web. For anybody who likes to read more theory on the octane rating:

https://en.wikipedia.org/wiki/Octane_rating

So I will carefully start with a static advance of 3 degrees and a max of 35 at 4000rpm. Regards

Alex
 
Re: high speed detonation

I have just had a 123 dizzy delivered last week, it went straight back to the supplier the following day! Why? After changing the polarity and luckily I had the sense to put a mark on the old Lucas dizzy and clamp plus body in case of any problems with the 123!! I could then change it back.
After taking out old dizzy fitted 123 all as instructions given, started engine, it ran for 30 seconds then gave up, after that the engine never fired up again with the 123 fitted, I even had a 123 Specialist guiding over the phone. Now normally my engine aways fires up 2 try even with a half flat battery and a worn out dizzy. The 123 was then taken out and my old dizzy of 40 year's old refitted to the marks I had made, and yes you guessed it, fired immediately. My supplier was contacted and I was asked to send it back, for a refund. I was informed by them that they had been having a lot of trouble with the 123 for BJ7 & BJ8! but I suspect it is a lot worse and other models are involved from what I have since found out?
I have been in touch with a few of the Healey racing people here in the UK and they just laughed when I asked them what they thought about the 123! Too unreliable I was told, also if they decide not to work they cannot be fixed easy, and definitely not at the road-side. You can aways get and old Lucas dizzy to work if you carry a few spare parts.
However I have now rebuilt my old Lucas dizzy and it is well packed and safe in the trunk should I need it.
In it's place after much liaison with the racing fraternity, I fitted a Mallery, that is what most if not all racers use in the UK, very solid piece of kit, it is mechanical and not a mini computer like the 123. I have re-tuned my engine to it, so far I am very impressed, I think I might change the condenser to a Lucas and keep the Mallery condenser as a spare.

https://i21.photobucket.com/albums/b287/vvs393/P72800088.jpg
https://i21.photobucket.com/albums/b287/vvs393/P2210005.jpg

Brian
 
Re: high speed detonation

Just finished with the 123 dizzy installation. After the first 100km I can say that the engine realy runs much better than before. I could reduce idle speed to below 800rpm (600 with clutch kicked) and performance feels much better. Setting is 12 degrees at idle, 25 degrees at 2000rpm and 35 degrees at 4000rpm. Installation was pretty simple.

Of cause that is compared to a pretty worn our Lucas.

Thanks for all your help. Two weeks ago I didn't know how a dizzy works. Thanks to the forum I saved a lot of money and had a lot of fun by doing the repair myself! Regards

Alex
 
Re: high speed detonation

Alex,
Which setting in the adjustable range did you use?
Lin
1960 BT7 in restoration
1959 Bugeye
 
Re: high speed detonation

Hi Lin,

I used the "B" setting based on the recomendation of Brits-n-Pieces. This recomendation was made on 15 degrees on idle and 38 degrees max. Based on multiple comments in this forum I followed the warnings and reduced it by 3 degrees which gives a max of 35. Hope this will do well. Tomorrow I am going on an extended trip. This will give the final prove.

Which setting are you using? Regards

Alex
 
Re: high speed detonation

Alex,
I am planning on using the 'B' setting as well with a max of 35 as you did. Let me know how your extended test goes.

Lin
 
Re: high speed detonation

Lin,

400km and the machine is running better than ever. I still do not dare to go up to 38 degrees but with 12 / 35 it's really running perfectly with a very solid idle and good throttle response. Have fun with it and let me now about your experience. Regards

Alex
 
Back
Top