Hey guys I was thinking the other day that I would like to build a race flathead. I like things Radical. Does anyone know of anybody that has built a direct injection set up for a flathead? I would be especially interested to hear of any vintage setups. Thanks Brad
Please clarify what you mean by 'direct injection'. When used in the gasoline engine context this means one or more high-pressure injectors per cylinder spraying directly into the combustion chamber as is typical of diesels. Electronically-managed forms of this (and systems with both direct and port injectors) are now very common - rapidly becoming the norm - in production cars. Mechanical flavors of this have a long history (including the B-29's R-3350 and a bunch of German aircraft engines of that era) but the only fairly successful passenger-car example I'm aware of in the pre-electronic era was the '50s Mercedes 300SL/SLR engines (those cars were a quart of technical worms in a pint pot, every decade or so the Daimler-Benz engineers have a nocturnal emission and squirt complexity jizz all over some subset of their products, like the hydraulic-everything and M100 engine in the 600s in the '60s, etc etc. most recently the Sensonic brakes...) It would not be surprising to find some postwar aircraft-engine-mechanic hot rodder deciding to take a whack at direct injection as an experiment, but I haven't seen it personally. Or are you referring to independent-runner stack injection e.g. Hilborn?
Unfortunately some rules for the vintage engine classes in some organizations don't allow for modern tech mods like true direct injection, 'puter eng management, or turbos. You might have to run heads up in displacement class against overheads but the satisfaction and self pride of success could be worth more than any trophy or certificate. A very interesting concept that might not be that hard to try with some aluminum head mods. Haven't happened to hear of it being tried yet, go for it and keep us posted. Ed
A vintage almost-direct injector, though not flathead...it is in one of the early 1950's little mags, an off-brand eastern mag I think. I could only locate this article again through sheer dumb luck, but maybe someone here can ID it. The setup was by an engineering student named Austen or Austin, the same guy who has recently been casting oddball FH manifolds for Ford, Ardun, Lincoln 337, and Lincoln V12. He made the metering stuff from oil furnace parts, and the actual injection was through the intake valve seat! The actual engine was a Ford OHV 6, 223 type, in a Model T drag car.
Brad, to help clarify, I believe you mean to ask about " direct PORT fuel injection ". You want the fuel nozzle to spray a direct shot into the port right at the back and underside of the valve. A dry manifold to just flow air, and then decide on whether or not you want the injector flow to be electric fuel pump- low or high pressure, computer controlled or mechanical pump pressure and timing, sound correct? If you go computer, you would need to decide on a Mass Air or Speed Density system. Closed loop or open loop to moniter and send feedback to the brain. Now if you keep the system " mechanical " it might be kept going for discussion on this forum. Similiar to a BOSCH type system ie Mercedes, V.W. etc. I apologize to the mods, as I am aware that the computer controlled system would be highly unfriendly to the forum- very sorry- TR
Hey guy's Thanks for your input so far and sorry about the confussion. When I said dirrect injection I meant Dirrect injection, strait into the cylender. I don't have any intrest in doing it electronicaly with a more modern EFI setup. I want to do it mechanically. Flathead's run relitivly low compression so getting enough fuel pressure shoudn't be too hard. A bit of math sould handle that. The hard part would be the pulse width and timing of it. That's where the brainstorming is. There's no such thing as a new idea with a flathead so has anyone seen it done before?
I haven't seen it done but while reading up on direct injection on some of the new cars in HRM, I was thinking the very same thing...why not try it on a flathead? The flatheads biggest obstacle in creating power has always been air/fuel mix flow. If a guy was to combine direct injection [possible through a bung welded/cast into the cylinder head] with supercharging/turbocharging, you might have a performer!
No, haven't seen it. If you look at what designs like the old Benzes I mentioned before did, you'd probably be looking at some sort of 8-piston injection pump running at cam speed, you'd need some sort of injector tip that'd live under combustion pressures/temperatures, the fun part is how you manage the timing and volume of the fuel to be injected. I'm trying to think of a way to do it that doesn't involve eight of everything...
R&C covered some Bosch mechanical injection system conversions of American sixes and eights long ago. They were from various Benz applications, I think, and were fundamentally based on diesel stuff. Some of the control was by cams that turned radially and also moved axially, giving three dimensional cam movement that was infinitely variable. The whole distribution and control thing was large and terrifyingly complex...no wonder Bosch bought up the 1957 type Bendix electronic control patents and started thinking about computers. (A PS on those conversions: The guy doing them was Ak Miller)
If you are seriously considering a mechanical system than an 8 cylinder injection pump from a Diesel is the way to go. Figure the cc's of the shot you need at max power and look for a pump that will deliver that. I believe the timing pumps for small high speed engines do have some retard built into them for low speed and idling and then advance as engine speed goes up. But that may not be necessary when you control the firing with a spark anyway. The nozzles of a diesel should handle the lower combustion pressures in a gas engine easily. I would think you would time the injection shot for the opening of the intake valve so as to mix the fuel in the whole charge?
Gas Pumper I was thinking the exact same thing! just use diesel injection stuff. As far as the timing goes if you could run the fuel timing a little bit retarded you would be able to increase your cylinder pressure quite substantially without having to worry about any kind of pre detonation. Of course with raised cylinder pressure in theory you would have to raise the fuel pressure correspondingly. That would suit lots of boost you'd think or maybe even lots of pop (nitro). I took a look at a set elco twin plug heads and it would probably be easy to adapt an injector to thread into the second plug hole on those.
Hey, FN; A few years ago, 10 maybe?, in a car-type magazine, possibly Hot Rod, was a feature on what you want. It was a v-8, chevy?, w/a form of direct FI. Trick it was, although calling it monkey-motion is being kind. I have the article somewhere, but don't know where to begin looking for it, as I strip my mags out, & nothing is cataloged yet. Anyways, it wasn't absolutely pure DI, as the injectors operated through the valve seats. Getting the fuel hot to vaporize, & also to cool the seats & valve margins. IIRC, it came out after the Coates Rotory Vavle system, & I never saw or heard of it again. I don't think it was geared towards hi-po, rather fuel economy. May be worth a look. I did do a quick search, but as I seem to have difficulty finding the correct search word/term, I didn't find it. Marcus...
Here's the original article for the Bosch system http://www.flightglobal.com/pdfarchive/view/1940/1940 - 0133.html
It would seem to me, if you are serious about doing this, a Mercedes V8 gas engine system would make more sense than a diesel system. You will also have to figure out how to drive the Fuel Distributor along with all the plumbing etc.
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