ET: Engine (Twin) Interesting Twin Magneto

Chris Launders

Well Known and Active Forum User
VOC Member
About a year ago I mentioned a friend had made a twin magneto by grafting two Lucas SR1's together with the rotors offset so it gave two full strength sparks. I've now got pictures of the said beast.
mag4.png
mag2.png
mag1.png
 

Marcus Bowden

VOC Hon. Overseas Representative
VOC Member
I don't see a moveable end cover so no manual advance & retard so must depend on an ATD Not keen on those things. BTH back in Vincent's manufacturing days were trying to do some thing similar. Brough's just fitted two mags, but this is neater, presume rotary magnet like the Scintilla which is the best mag I've ever had but now run out of parts, require distributor block & brushes and a set of points for my twin item and a set of points for the single item, both to be used on a repro Lightening and other on the only chain driven timing trials iron that Pat Wilson passed onto me done by the factory. !
bananaman
 

greg brillus

Well Known and Active Forum User
VOC Member
Its a very similar magneto to what John Trease here in Australia (who sadly passed away last week) ran on his very potent period 3 Harley Sportster/Norton solo race bike. This was a methanol burning twin on about 16:1 compression and reported to have around 130 HP a very powerful bike that ridden by the likes of Cam Donald holds the record in the P3 Unlimited class at Phillip island at a time of around 1:46 which is very quick. This shows the potential of the output from magneto's that put out more amps than an equivalent coil ignition.
 

stu spalding

Well Known and Active Forum User
VOC Member
The SR1 has the points of max flux density at 155/205 degrees, just right for a 50 deg V twin. I,m sure some enterprising soul could make a points cam to suit and fit the twin end cap and rotor arm. (don't look at me, I'm just muggins down at shadetree engineering) Cheers, Stu.
 

stu spalding

Well Known and Active Forum User
VOC Member
Hi Bruce, mine was offset. It came from an engine driving a refrigeration unit and a timing disc on the shaft gave the figures mentioned. Cheers, Stu.
 
Top