Blic magneto - no discernible difference when advancing or retarding...

[Ruairidh Dunford]

I have been playing around with the timing on the Cup Model and discovered that, despite the points holder rotating as it should when moving the control lever on the steering column, it makes no difference to the running of the engine. 

This is not the case on the Chummy, where full advance and full retard alter performance greatly.

Is this a feature of "some" BLICs or is something amiss? 

I would like to be able to alter the timing manually, for obvious reasons.

[Charles P]

Obvious comment, and you know more than most, but weren't the actuating linkages different lengths for different mags?
Is it moving enough? I had to mess about a bit to get it right on my car.

C

[Ruairidh Dunford]

It appears to be Charles but I will check again, I know there were at least two types of arm for the throttle cross shaft, I think I have the correct one.

The BLIC on the Chummy is very sensitive to movement, this one, not so much (if at all)??

[Hedd_Jones]

does manually advancing it (at the mag) make any dofference

[Ruairidh Dunford]

No, it is most unusual.

[Alan]

Is the magneto internal timing correct? That is position of coil relative to magnet at points opening? I’m not checked out on BLIC mags but it makes a difference on some.

[Ruairidh Dunford]

I do not know and have no idea how to check, any pointers gratefully received...

[David Cochrane]

I also find that varying the Chummy's timing (with a BLIC) makes a considerable difference to the performance. However, with the Cup (which has a BTH) it seems to have hardly any effect. The Chummy has the longer lever, the Cup has the shorter one. I assume the different lengths of levers were for different magnetos, but I have never seen anywhere which lever goes with which magneto. I would like to fit a longer lever to the Cup to see if that makes any difference, but I haven't got one, so one day I intend to fabricate an extension and braze it on to the shorter lever.

[stuartu]

Ruairidh and David,

I have the wrong lever on my Ulster operating its BLIC. Being a lazy person, I couldn't face wandering out to the garage to check which of the two levers it is so, as ever, I consulted the archive.

By looking at the 1923 (pre BLIC) parts list I see that the only arm illustrated is BF 15 which applies to the Scintilla. Later lists use the same illustration (which shows the shorter of the two arms) but label the drawing as both BF 15 and BF 29 - the BLIC arm. The BLIC arm is the longer.

This makes sense to me because the effect of the wrong arm on my car is to give a slightly reduced movement of the arm on the mag; the difference is small, perhaps 1/4" of linear movement at the magneto. I set the hand control to give full advance correctly and accept that I cannot quite achieve full retard. So now David knows which arm is which but Ruairidh will be sorry to learn that, despite what I am obliged to describe as my short arm deficiency, moving its control lever still has a noticeable effect on the engine's response. So being wrong armed is unlikely to be the reason for the lack of response he describes.

I hope I may have eliminated one possibility and am only sorry to have no suggestion for a cure. Over to the magneto specialists?

Regards,

Stuart

[Mark Dymond]

A timing light on the flywheel would clear up how many teeth advance \ retard range you have available. ideally mark TDC to confirm you are in the ballpark.