Lagondaforum » Engine » Ignition » Automatic A/R mechanism for magnetos

Tim Wadsworth	May 12, 2017 10:35 pm
Subject: Automatic A/R mechanism for magnetos I am thinking of making an automatic A/R mechanism which would fit between the two halves of a Simms Coupling. It would extend the width of the coupling by just 9 mm (it should be possible to move most mags back by this ammount). It would have a range of up to 25 degrees advance and could be "tuned" to requirements by changing the centrifugal weights. What do other owners think ? Would this be useful / practical ?
Attachments: Auto Timing Device 2.pdf (Filesize: 91.90 KB)

Tim Wadsworth

May 12, 2017 10:35 pm

Subject: Automatic A/R mechanism for magnetos

I am thinking of making an automatic A/R mechanism which would fit between the two halves of a Simms Coupling. It would extend the width of the coupling by just 9 mm (it should be possible to move most mags back by this ammount). It would have a range of up to 25 degrees advance and could be "tuned" to requirements by changing the centrifugal weights. What do other owners think ? Would this be useful / practical ?

Attachments:
Auto Timing Device 2.pdf (Filesize: 91.90 KB)

Colin M34	May 12, 2017 11:10 pm
Subject: Re: Automatic A/R mechanism for magnetos Hi Tim, These are well understood and very practical. I have one made by Simms that I am currently not using and think it might be worth investigating using one on a rolling road. It would also be interesting to investigate the benefits on a 16/80 engine, mainly because it revs much more than a standard 2 Litre. I am not referring to your engine of course. I suggest you contact me privately. Colin M34

Colin M34

May 12, 2017 11:10 pm

Subject: Re: Automatic A/R mechanism for magnetos

Hi Tim,

These are well understood and very practical. I have one made by Simms that I am currently not using and think it might be worth investigating using one on a rolling road.

It would also be interesting to investigate the benefits on a 16/80 engine, mainly because it revs much more than a standard 2 Litre. I am not referring to your engine of course.

I suggest you contact me privately.

Colin M34

Tim Wadsworth	Dec 11, 2017 11:43 pm
Subject: Re: Automatic A/R mechanism for magnetos I have completed the prototype of the automatic A/R coupling and have got the width down to just an extra 6.5 mm. It was necessary to remove the 10mm nut on the end of the magneto shaft but this shouldn't have any effect as the coupling is held on by a key. Now on road trials and so far so good. About 10 deg advance at rest going up to full advance of 30 deg at 2000 r.p.m. More trials (when the weather gets a bit warmer !) and a planned full rolling road test in the New Year. Colin - did you ever find the original you thought you had ?

Tim Wadsworth

Dec 11, 2017 11:43 pm

Subject: Re: Automatic A/R mechanism for magnetos

I have completed the prototype of the automatic A/R coupling and have got the width down to just an extra 6.5 mm. It was necessary to remove the 10mm nut on the end of the magneto shaft but this shouldn't have any effect as the coupling is held on by a key.

Now on road trials and so far so good. About 10 deg advance at rest going up to full advance of 30 deg at 2000 r.p.m. More trials (when the weather gets a bit warmer !) and a planned full rolling road test in the New Year.

Colin - did you ever find the original you thought you had ?