A couple of years ago I acquired a 2up 2dwn crank and camshaft. I didn't feel the cam was "aggressive" enough to take advantage of the features of this type of engine. So I got it reground to a grind I have used with 4 intake port flathead T engines. The cam is now on its way to me.
The crank is T stroke with A size journals and drilled for pressure oil. I need to make a decision on rods and pistons, so the recent posting about aluminum rods was timely.
As I have a spare Sherman head, I will likely run that
I also have a couple of sets of castings for the Fronty front oil pump and RH side water pump with magneto mount, so probably that.
As the cam will accept a VW oil pump at the back, maybe this is the opportunity to go "dry sump"!!
Les look at the sharp drop on the cam in the actual engine.
Trouble is that was not available to me!! Also I'm building a "street engine"!
Can you explain this type of engine in more detail for the uninitiated?
Dan, a Model T engine has only two intake ports. By making a crank shaft that has two in front aligned and two in the rear aligned, it makes the engine a four port and so lets you have one fire. then three, then two and then four. Any firing order can be used but the efficiency is improved by evening out the power pulses rather than one two, four, three. That system makes you get the front two in line while the back ones do nothing. The air must first go twice to the front and then twice to the rear as if it was controlled by traffic lights. The two up two down is more efficient because it alternates the firing into equal distribution. Ed Winfield also tuned the intake manifold runners so that the air pulses did not overlap or interfere with one another. Glen Chaffin sells that manifold which his son Mark is manufacturing from plans drawn by the late Jim Cullinane.
Further, it allows the efficient use of a much more "aggressive" camshaft ( much longer duration). The cam I have had made is not as radical as shown in Franks pictures, but is a lot more than any of the available ones
Doesn't it make for a lot of engine vibration?
No, with big enough counterweights it runs as smooth as any counter weighted T engine (and probably smoother than most)
I will have mine dynamically balanced
Thanks for the explanation!
Are there any other external cues that the engine is setup this way other than the manifold?
What would the results be if it was dynoed compared to a stock T engine?
Les, why not save all the time of setting up two different pump set ups and stack up a pair like this unit I found. As you probably know, the scavenge pump gears need to be larger that the pressure pump gears.
Well that is quite the setup. Too bad the plate on the one you have is broken!! I suppose it could be welded or it could be replaced by one of the castings I own
Les, Thanks but I have another plate just like it. Keep us informed on your progress.