G`day fellas new old bloke here from Oz For decades flat heads have sucked me in, their simplicity fascinates me to no end. Sure they have their shortcomings for certain applications but in some ways they work similar to Diesel, good torque down low and reliable but way less efficiency. As my Avatar name suggests, my point of focus has been combining a pre-chamber and combustion chamber together as one not just using a separate pre-chamber. Im old so sorry for the pixelated pics done on paint with the help of arthritis! The bias is on one side of the valves shrouding the other where to my surprise Toyotas latest eco engines employ to great effect. https://imgur.com/j4Mdj5k The exit although not visible in my pics is shaped like a small banana or quarter of a circle wedge as an exit passage. This is my thinking to arrive at a tumbling charge that goes deep down to the bottom of the downstroke on a very under-square design that creates a strong clean pull effect. https://i.imgur.com/yEmQILb.jpg (valves like most of it is not drawn up to scale - they would be larger but didnt want to interfere with the general shape funnel shape) This design would allow the use of short inlet manifold runners and the usual exhaust design. Spark plugs would a small industrial units with the pre chamber already on the end which are common for industrial and Formula 1 but not the street. These would have 2 - 3 holes biased towards the gas flow path to help the flame front exits along the tunnel shaped elephants horn etc. Essentially this is like 2 pre chambers as a combustion chamber. Another version of this design is to swap the inlet and exhaust sides to keep the chamber cooler via inlet charge flowing over exhaust valve yet reshape the elephant trunk port to curve and swirl rather than tumble and create perhaps even more torque than the tumbling design. Can anyone put me on to a fluids dynamic dude that is able to help me further my dream of making a flat-head more efficient? Also your constructive views are welcome as Im not trying to outdo an OHV design but to raise the efficiency of the flat head so it can use fuel more efficiently.
I reckon if it can be done it was done to a flathead Ford.If it couldnt be done,someone tried it anyhow. Likely one of the most the most highly developed sidevalve engines ever was the old Harley-Davidson KR.At the end of the day the best ones made 56-57 bhp a 6500-7000! rpm.This from 45 cubic inches.Those engines used a Ricardo style combustion chamber and a CR of 5.95-1.I sure do wish you good luck with your project.
Thanks Steinauge yes the v twin is what has been polluting the thinking of the males in my family for close to a century now. However that didnt stop us also getting most of our time tinkering with all forms of flat head engines from different makes. The V twin allows me to place the sparkplug in the best location without worrying too much about indexing custom made directional pre-chamber plugs as planned and can just use off the shelve pre-chamber plugs. Inline applications will need indexing to make sure the flame front exits as planned. https://i.imgur.com/ASnE7LW.jpg It is like a 3 stage combustion process where the first is inside the pre chamber of the plug, then the combustion chamber before being forced through the trunk into the cylinder area. (Trunk design as mentioned could be shaped for tumble or swirl where in illustration only tumble is shown for ease of demonstration) I focused primarily on the same aspects of human breathing where through the nostrils => nasal cavity => Pharynx (curved passage) then into the lungs of the engine. A dual outlet with 2 trunk ports of smaller volume could also be applied to create 2 directional swirls like a Helix pattern rather than one or 2 swirl or tumbling mixtures. As guessed by the witty ones this design needs to run with very long rods to maximize slower burning environments rather than fast burn and low rpm applications not exceeding 5000rpm at best. My aim is torque throughout rpm range from idle, smooth and reliable operation, fuel economy and less parts eg. compact design. I find that most modern engine applications move torque higher up the rpm range in most applications using gasoline except the new very complex small turbo engines that are full of parts that will break down over time or be a nightmare to repair. Hydraulics and torque creation has always been our passion. We love less electrics, more analogue and mechanical solutions usually infuriating the tech addicted narcissists, that are hell bent coding away to convert our world into a lifeless digital prison. Ecus will be in everything in time, this is just the opposite where I want to see better applications now that we have so many millions of tinkering minds that still dont mind using elbow grease. Typing walls of text is hard enough for me as it is for you fellas to read! If this design was tried then for almost 100 years and 3 generations of tinkering, racing and friends with the same passion has definitely escaped us even with copious print matter covering H Riccardo`s works. We have yet to come across any 4 stroke, 3 stage expansion event design like mine or any at all. If someone has please point me towards it and will greatly appreciate it.
I'm no where near smart enough to understand all this, but. as a flathead fan, I'm eager to hear how this all works out. Good luck with this project. Please keep us updated.
Speaking of highly- developed sidevalve bike engines, you'll love this. An old buddy of mine, who you've probably heard of, Alan Sputhe (RIP) was one of those guys who was a genuine thinker, and then could build it- kinda like a Smokey with a V-twin. One of his later "fun" projects was another friend's '37 Scout vintage road racer. The class it ran in was an if it looks stock you can run it thing, and Alan was in hog heaven. He put larger valves in it until they were out to the cylinder bore, so he just casted up some new cylinders with the valve pockets and guides moved out about 1/8" and went big on the valves. Then, the Scout 3-speed trans was unacceptable, so he machined out the inside of the trans case and installed an XR-750 gearset, and made it work- and it looked stock, so OK. The bike won every race it was entered in, but needed a rebuild after each race- a bit ragged edge.
Alan will forever be one of our Heroes. One of his engines was drag raced for 11 year down here with no issues. The biased flow from the edges of the valves into the cylinder chamber is genius, I cant recall seeing any pics of the setup from inside of the setup you mentioned but would take a stab to imagine the non exposed valve area was shrouded intentionally to create some serious tumble in his setup. FYI my favorite non Sidevalve engine is the Buick "nailhead" v8 eg. torque
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