tman, Thanx for bringing this back up. I remember it from when it was new but reread the whole thing this morning. Insanely interesting tech. I wish I had half as much talent in my whole body as some folks on here have in their pinkie finger.
Yes, I ran it in the rolling road. From what I can remember it made good hp. The motor was a stock 255ci fitted with the twin plug heads, 270f cam with .395” lift, triple 1-3/4” SU carbs, stepped exhaust and electronic ignition with programmable advance curve. From memory it made 147 hp at the flywheel. I will see if I can find the printouts later.
. with the motor as above except for the cam and heads was 113hp. So cam and heads added 34 hp. How much was cam and how much was heads I don’t know. But for a stock 255 with just some bolt on go faster bits it wasn’t too bad.
Gr8 planning and even gr8er if not spectacular MACHINE workmanship,BUT, correct if I am wrong; the main or sole purpose for having dual plugs is to “fire” or “ignite” any and all remaining fuel that was left over or did NOT get totally burned by the first plug!! Right or Wrong?? Looks like a lot of work and prep that will make little difference in the outcome of the cool flathead. I am not trying to bash your beautiful machine work, just wondering what effect(if any) dual plugs on a Flatmotor will show??
Pete, I just discovered this thread. Great work, truly innovative. To comment on Flatheadjohn47's question there is more to it than just two sources of ignition to complete combustion. Twin sparks allow one to increase the burn rate of the charge, to reduce total ignition lead, and thus reduce the "negative work" done by having to ignite the charge against a rising piston. I do like the fact that with two separate distributors there is the opportunity to stagger the timing. Perhaps one needs more advance than the other? Have you tinkered with varying the timing between the two Pete?
I did say right at the beginning of this thread that the usual costs involved far outweigh any gains, and it’s for that reason I did my own, well that and I don’t have the money anyway. What the twin plugs did do though is smooth out a very lumpy idle.
The satisfaction here is in the doing, I believe, not in the performance gains, however nice that becomes. And knowing the modifications have worked to improve things is nice as well. But enjoying the journey for some is far more important, at least when you have the time.
The Jalopy Journal
