123ignition
- Thread starter olesto
- Start date
Tom W
Active Member
I don't have one on the Rover, but I have one on my Jag. The advance curves in the 123 are grouped by total advance, around 4 curves per total advance. Within a group of a given total advance, there are then different levels of aggressiveness, i.e. how soon total advance is reached. Pick the group of curves that gives the same total advance as the original distributor, then set it to the least aggressive curve. Go for a test drive. The engine should run ok with this curve. If not, then you need to go back to first principals and re-check the static timing. There's some ambiguity and inconsistency in the manual and between models about where the static timing point should be set. If all is ok, then move up one curve. If the engine starts pinking after you've moved up one curve, drop down to the previous curve. If not, try a more aggressive curve until the optimum is found. With the one on my Jag, I found the curves were all on the aggressive side, so I settled on the least aggressive one with the right total advance.
olesto
New Member
OK, thanks. Seems like curve 8 runs best. According to my workshop manual the 2200TC has a max total advance of 30-34 degrees, reached at 3,250 rpm. Curve 8 corresponds to a max of 35 at 4,500 rpm, and is the least aggresive of the 4. But I'll do some more road testing. If any others does a similar upgrade, please be aware of the + and - cables that will be squeezed towards a corner of the engine head. I turned the distributor 45 degrees clockwise and moved the 4 cables correspondingly to avoid melted cables.
. PVC insulation on auto cables should be good for 140ish degrees before any damage occurs.