123 distributor.

[saltiga]

To follow on with distributors and advance curves.. I have set my 123 on number 8, results, 15deg, 700rpm, 20deg 1600rpm, 25 deg 200rpm, 30deg 2600rpm , 35deg starts at 3400 and hardly advances after that, If I connect the vacuum the timing goes way over like 25deg at 800rpm 30deg at 1100rpm, 35deg at 2000 rpm so I have left the vac off--disconnected . Has any one checked their 123 and recorded the results?? If so how does yours shape up?? Saltiga

 

[andrea]

I have my AH equipped by 123 Distributor after my restoration, very satisfied after 3 years-sorry I not remember exactly my regulation,
can be the number 7 curve,
vacuum connected, engine turn very well "SUPER", only difficult to start when engine is cold
https://picasaweb.google.com/112770819864514987162/AHSPINTEROGENO?noredirect=1#5748758593370304482

 

[EV2239]

Saltiga

Peak torque is at 3000, so if you can retune the 123 to give 35 degrees by then, I think you'll get more power earlier.

 

[saltiga]

The power seems quite ok at these settings and with vac disconnected, I will take it out and give it an 0 to 60mph test ,this will tell if its tuned good enough, at the moment I cant keep the exhaust to manifold joint tight, keeps coming loose, so am in the throws of making a bracket similar to the one used on the 100/4's. Thanks for your help Saltiga

 

[DerekJ]

The only purpose of the vacumn advance is as an economy device at low throttle openings.

 

[johnea]

In addition to what DerekJ says, the vacuum advance should also give a better throttle response.

 

[saltiga]

Thanks for that info, I did not know that, If this is so how come my timing goes way out when the vac. is connected. also the 123 book says the advance starts at(degr.crankshaft) 1000 I assume this is 1000rpm If I static balance at 10deg(as in manual) It strobes at about 13deg at 600rpm, yet the advance is not supposed to kick in until 1000rpm, maybe I'm making a mountain out of a mole hill!!!! Saltiga

 

[SideShifter Tri-Carb]

Why not adjust the static timing for a lower advance with the vacuum connected? Not familiar with the 123's adjustment, but that what be my first approach. Sounds like the dizzy its advancing as designed, you just need to pick the starting point of where the advance starts from.

 

[EV2239]

Saltiga

You do the need to worry. The figures you've given are pretty near optimal, so if you leave it #1 you'll have a good result.

Timing is something you get a feel for as you get used to the engine. I know from driving mine if it's slightly retarded or advanced. The former means it doesn't pull so well and the latter makes for a roughness and possibly pinking. Just give it time and don't worry. It'll be good.

 

[saltiga]

Thanks for the confidence boost. I have googled vacuum advance on distributors and found it very interesting reading, as DEREKJ says its for better throttle economy, and its not unusual to have the advance as I have with the vac. connected. the explanation of various throttle openings have put my doubt to rest, I took a guy who owns an MG"B" for a run , his comment " the "B" does not perform any where near the Healey, cant get over how smooth is runs and the elimination of any scuttle shake, puts the "B" to shame. Must say this, I have fitted performance superlite mags, and strengthened the chassis and fire wall on the rebuild to about 30% or so stronger without much more weight addition Saltiga