AC Owners Club Forum > AC Weller Engine

Ignition Timing - 12 1/2 before T.D.C.? Or differently with modern fuels?

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SpqrEddie:
Hello!
CLB engine were designed in the 50ies when 72 octane pool petrol was avilable. And timed at 12 1/2 degrees before T.D.C.
CLB after 2457, were already advanced to 21.
now that the minimum standard is 95 Octanes, should the timing be altered? what is is the reccomanded practice?
Should as well engine prior 2457 being timed to 21 degrees?
Thanks!!

Big col:
In all honesty I don’t know the relative numbers. The way I do it now is the way I learnt from my Daimler days.
It is important that both timing and carburettor tuning are done together or knowing that one is correct before setting the other.  Run the engine up to temperature, set the RPM to around 2500/3000. Loosen the distributor clamp and turn the distributor body too and fro to reach the highest rev rate then clamp the body up tight. Job done.

SpqrEddie:
Hello!
anybody would know what should i see with a strobo lamp?

I can see three markings on the flywheel: a "5", a bar "I", and a "1 I 6"

With the strobo lamp i can see the "I" with the motor running very slow.

At what should i aim?

Thanks! and sorry the manual is not very helpful on this!

Eddie

Big col:
Hello Eddie,

 Again I am no expert, but I don’t think you check the ignition timing on the flywheel.
I think it is on the front pulley, the one that drives the water pump.
There should be a mark for Top dead centre and one for (I think 10 degrees before) top dead centre.

Make sure number one cylinder is at Top dead by removing the sparkplug. Then wind the engine backwards to the 10 degree mark.(or guess it). Then use a light or multi meter to set the distributor till the light just goes out. Lock it up then run the car to get warm.

With a strob light you should see the mark on the pulley move anti-clockwise as you rev up the engine. It should move round relatively to the engine speed. More revs the more the mark will move.

Colin

Big col:
Eddie,

One more thing, make sure that when the piston is at top dead centre on number one, that the valve are rocking on number one and not compressed.
Also make sure that the rotor arm in the distributor is in line with number one plug lead.

Colin

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