Yes, it turns 8000 rpm! Anyway he says 35 deg for a single plug and std setup and probably 33 deg for twin plug. He runs 28 deg, but has very reworked combustion chambers.
Ignition timing for twin plug heads
- Thread starter vince998
- Start date
Yes, it turns 8000 rpm! Anyway he says 35 deg for a single plug and std setup and probably 33 deg for twin plug. He runs 28 deg, but has very reworked combustion chambers.
Time traveller makes sense again. this may be why bth supply 4 coils(one for each plug) An e to the manufacturer may be a good bet, if mr grosset dosen't know then you really are in the ---t.
You can run a double coil on one cylinder but only when each coil gets its own primary feed (or earth)impulse (i.e not running wasted spark).
So why can a double coil fire two plugs on one cylinder in this setup, and not when another coil is doing the same next to it?
Maybe the coil firing into the combustion chamber with the least pressure is getting the lions share of current, although on the primary side this can´t happen. Or?
the only applications of double ended coils i have worked with are jap fours, harleys+ citroen 2 cv's. all of these use a wasted spark so are only really firing one cylinder at a time. one end produces a positive spark its mate a negative one.never seen one double per cylinder. i expect some clever person has done it, sounds like mr grosset has not got it quite right just yet, or dyna coils are unsuitable in this application.
Two positive sparks?
When i remove one of the HT cables (or just pull it off the plug) from a Dyna double coil, the other side of the HT circuit continues delivering a spark.
Try this with a Jap coil and the coil stops working.
What i´m trying to say is that with a single fire ignition system (i.e the spark is timed for each cylinder using two pick-ups or two sets of points & 1 cam or Signal shutter) you have to put both leads from a double coil on one cylinder?
Dyna sells such an ignition system, but can´t tell me why using 1 coil (both leads) on 1 cylinder won´t work when running a wasted spark system (1 pickup or set of points & double cam or signal shutter)
According to the past results you have been messing with this trouble for the last 15 months, maybe it's time to beg, borrow or steal a replacement ignition system to swap it out to discover if the "problem" exists afterwards. Dynas own web site says 3ohms like you have are only for racing, 5 ohms for steet use!
Vince - may not be relevant but my big motor has twin plug heads and is fitted with a Pazon ignition. Bob Dunn (who built the engine) designed the advance curve mainly to ensure that fully retarded position is 2 degrees BTDC (to avoid misfire kicking back against the electric starter sprag clutch - and wrecking it!!. The engine is fully advanced at 28 degrees BTDC above 2000rpm. The Pazon also defaults to fully retarded ie safe - if battery voltage accidentally gets low.
regards
Bob
regards
Bob
Hi H,
Firing twice as often, and the battery is having to supply 2 coils at once doing this.
Maybe your right.
My knowledge of vehicle electrics doesn´t extend to calculating the necessary momentary current availability to allow this.
Think about it chaps! Years ago I used to run a Range Rover with a V8 engine. In those days they were equipped with one coil and a distributor with points . No problem firing all eight cylinders at maximum revs, so a coil has a very easy time of it on a V twin Vincent, even with the uneven firing interval.