Pondering about flathead potentials

[frnkeore]

It doesn't have the V8 mystic but, a much better Ford flathead, is the 254 truck engine, 3.5 x 4.4. Bored .090 it would be 267 ci.You could also offset grind it, if you can find a rod with a smaller journal. Maybe a Chrysler FH 6 rod?

You can port that engine, with good results and the Ex path isn't restricted. But, parts are hard to find and no speed equipment for it.

[Nikolas Ojala]

Here is what I've pondered once or twice. Ive never laid hands on a flat head, however I have wondered with the exhaust ports exiting through between the cylinders would it be possible to machine ports like a two stroke diesel through the cylinder wall into the existing port, obviously blanking the exhaust port off below the exhaust valve.

You wish to see a two-stroke engine. Here is a link for you: https://www.ac-aero.com/

[Nikolas Ojala]

27:29 Design for combustion chambers ... is a secret.

I just hope that some day they would reveal their secret combustion chamber design.

I was thinking: Someone dare to ask?

It seems like we are slowly entering an age of battery-operated electric cars. Car industry does not look like probable thieves of flathead designs.

[Nikolas Ojala]

I am still talking about the alternate combustion processes which resemble very much Diesel, and no throttle control is used.

One possibility would be SVPC (single valve per cylinder) in which there is only one poppet valve per each cylinder, opening to a nice round combustion chamber. There swirl would be possible. However there should be another low pressure valve to change gas flow between intake and exhaust. The other valve could be rotating, flapping or what ever.

Kind of extreme solution would be leaving the other valve completely out or using only a reed valve to prevent exhaust gases flowing to the intake side, then pumping excess amount of air, and using a turbocharger for that.

There is also at least one patent (perhaps even more than one) that describes such method: WO 2015/166264 Al

Obviously Mr. Andrews did not mean his valve invention to be used in flathead engines. Which is easy to understand. But, my opinion is that a single-valve invention would be most useful in a side-valve engine, especially L-head, because the single valve enables improved shape of combustion chamber and also higher compression rate. In any OHV or OHC engine those are not issues waiting to be solved. But in a flathead engine they are very real.

In the drawing there is one high-pressure poppet valve (2) and one low-pressure valve (1) which seems like a reed valve but in principle it could be also some other low-pressure valve.

Andrews_single_valve_patent_Fig_11.png

How much different this could be if there was also one more low-pressure valve on the exhaust side? I mean, how necessary would it be? I think it would be required if any kind of supercharger was used.

I was also thinking that if the high-pressure valve had variable open time, EIVC could be used. The reed valve prevents using LIVC.

There are plenty of possibilities. For example there could be one high-pressure valve and one or two controlled low-pressure valves, one low-pressure valve for intake and possibly another for exhaust. Those low-pressure valves could be some kind of slide valves. Regardless which would be the particular low-pressure intake valve type, it would be useful if its timing could be easily controlled. I was thinking something like Pattakon DVVA desmodromic valve system could be useful. If the low-pressure valve was sliding it would not need a lash adjuster (manual or automatic) of any kind.

Pattakon_DVVA.gif

[Nikolas Ojala]

27:29 Design for combustion chambers ... is a secret.

I just hope that some day they would reveal their secret combustion chamber design.

One more thought: The well known fact of L-heads is that the gas mix arrives into the combustion chamber, does a tight 90 degrees turn, flows towards the cylinder, does another tight turn and then follows the piston into the cylinder. To improve flow, the chamber should be re-designed so that instead of two tight 90 degrees turns the gas mix would do one not-so-tight 180 degrees turn.

I looked again the picture of the L-head in which some amount of metal was added on the exhaust valve side. It would have been counterintuitive to add metal on the intake valve side, which they did not. What they did later, is not visible in the picture, but one could guess some CNC milling followed. They have read scientific articles about intake runners and chamber shapes, and concluded that there is a thing that could be done to an L-head.

Think about the hemispherical combustion chamber and head, why it was something, and it still is. The flow does one nice curve towards the cylinder. I think that idea was repeated in this case. So, in an L-head it would not ever become a hemispherical combustion chamber, but that is not essential. Essential is the idea behind that shape.

[frnkeore]

To improve flow, the chamber should be re-designed so that instead of two tight 90 degrees turns the gas mix would do one not-so-tight 180 degrees turn.

Wouldn't it be difficult, if not impossible to have any compression, with a layout like that?

[Nikolas Ojala]

So, the idea would be to give a preference to the area around the intake valve and between the valve and cylinder.

If we look at the picture in which metal was added to the head, we see that they did not add extra metal to the path between the intake valve and cylinder.

Flat_head_with_added_metal.png

A glimpse to Mark Kirby's flathead reveals what he did to area around valves.

Motor_City_Flathead_Combustion_Chamber.jpg

So, combine these tricks to improve flow from the intake valve into the cylinder. My drawing only shows the possible idea. The exact implementation may look very different. Probably simulation would help.

Possible_L-head_combustion_chamber_milling.png

[Pete1]

That welded head looks like something I did many moons ago.
CNC machines made it much easier these days.