The Triumph Dolomite Club - Discussion Forum

GrahamFountain wrote: ↑Tue Jun 02, 2020 5:46 pm
The only related limiter I've heard of is that there was a centrifugal weight and spring on the back of the competition version of the rotor arm. Supposedly, that would come out and short the spark to the opposite terminal if the revs got too high. But I've never actually seen one of those. And I was only told that in answer to the question why the Sprint's rotor arm was such an odd shape.

Hi Graham, I think you are referring to one of these. This is specifically a Lotus Rev; Limiting Rotor Arm. Stamped Lucas 410299 and "1100 rpm".

The story goes that when the Lotus Elite was first imported into the USA the dockers would race them up and down the quayside. So Lotus fitted these rotor arms to stop that. The 1100 rpm is the dizzy rpm at which it triggers or 2200 rpm crankshaft speed. And as you say the spring loaded movable bit moves to the left in the photo and conducts the spark energy down to the ring which is connected underneath to the dizzy spindle and earth.

Tony.

Aye, that's probably what the guy was talking about. I knew the 44D was also used on a Lotus, but didn't know which.

But that way round, i.e. developed later, it don't explain the odd shape of the standard rotor arm.

Graham

Counterweight balance...

Most Bosch dizzies had these rotorarm counterweights from 1874.

Jeroen

1874?

soe8m wrote: ↑Wed Jun 03, 2020 7:52 pm Counterweight balance...

Most Bosch dizzies had these rotorarm counterweights.

Jeroen

Yes, but in the context of a Lucas distributor, it seems odd.

GrahamFountain wrote: ↑Wed Jun 03, 2020 7:54 pm1874?

1874ad.

soe8m wrote: ↑Wed Jun 03, 2020 8:16 pm

GrahamFountain wrote: ↑Wed Jun 03, 2020 7:54 pm1874?

1874ad.

Reference?

Still interested to know what engine had a Bosch distributor with a counter balanced rotor arm in 1874 CE, when Robert Bosch didn't start the company till 1886?

Graham