Engine tickover RPM and charging light

[sheddweller]

Hi to all
I have recently joined the forum having spent the last 18 months building a special based on a 1937 nippy chassis ( sadly devoid of any mechanical componants but with a V5c ). The axles, steering box , gearbox are all 1937 Ruby and the engine is 2 bearing from 1933 .I am very close to finishing my special and slowly working down a snagging list. This week i had the engine running for the first time , roughly 3 turns on the starter then burst into life which took me totally by suprise.
I have a couple of questions and i am hoping to tap into the knowledge of others on the forum.
1 - What sort of RPM should i be aiming for on tick over. My car is running an 1 1/4 SU fed by an SU pump and mounted on a log type inlet manifold. Number 6 needle and blue spring. At the moment the tick over is approx 800 rpm but i need to do some tuning as it is running on the rich side at the moment. 
2 - At the current tick over of 800 rpm the charging light is glowing but at revs 1000 or above the light goes out and the cutout contacts are closing so is this normal ?. 
The car is running 12volts and wired negative earth, the dynamo being converted to 12v .
A few more details regarding my car are as follows
The engine as previously mentioned is a 1933 2 bearing engine fitted with a brand new 1 1/2 splash feed crank and rods which carry shell bearings.
Remote oil filter and electric water pump.
1 1/4 30 degree SU carb and SU pump , log type inlet manifold.
Ulster style exhaust manifold
4 speed fully sync gearbox
Aluminium over steel tube bodywork with boat tail
I do have photos but need to get to grips with posting them.
Any advice regarding the above questions would be greatly appreciated.

[Ian Williams]

Welcome to the forum. In answer to your questions, Yes this is normal.

[John Cornforth]

Hi

That's a nice looking special.

All cars are slightly different, and 12 volt conversion might affect things, but an 800 RPM tickover and an ignition light that goes out at about 1000 RPM sounds pretty normal to me.

The SU mixture strength can be adjusted at idling speed, the needle has a pronounced taper around the idling position so only a small tweak to jet height via the adjusting nut is needed. I find a Colourtune plug useful, but the experienced can tell by ear. The effect of the adjusting nut on mixture higher up the rev/power range is small, and any mixture adjustment there is supposed to be accomplished by changing the needle.

I don't know whether you are using a 1933 low compression head or a post 1936 high compression head, but I have found that the latter is happier with less ignition advance, possibly because its design induces more turbulence.

[sheddweller]

Hi John, many thanks for the re assuring reply. The head is a high compression one. As mentioned it is running a little rich at the moment so some tuning required. It is very responsive without any popping or backfiring and quickly returns to a nice even idle so i must be somewhere near.
Once again many thanks

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Many thanks for your reply Ian. Very re assuring