Lucas Mechanical PI System Model

[Vixen]

I am still working on the design of the body. One end will have the cam/wedge to control the shuttle position, the other some form of drive coupling (very small Oldham style?). Both ends will have to have a return line for fuel that leaks past the shuttle or rotor. I will also need to select a suitable way to retain the fixed shuttle stop. For the finished item some form of Loctite would work, but in the experimental phase it needs to be a removable mechanical fixing. I am looking at either a very small grubscrew in the rotor, maybe M1.6 x 2, or a M1.4 screw from the coupling end.

Roger,
"When in Rome do, as the Romans do".  When in Switzerland, "make it like a Swiss watch".

Hope that helps. 

Mike

[Roger B]

I turned a pair of nuts for the rotor from 8mm brass hex, one short one for the control end and a long one for the drive coupling. As anticipated I had to cut a 0.5mm run out groove at the end of the threads so the nuts seated on the rotor. I could then assemble the rotor and sleeve using shim washers to centralise the ports.

I will need an electric fuel feed pump for the trials, potentially working up to the prototypical 7 bar. The Modelcraft pump I have been using struggles to reach 2 bar so I wondered if I could modify one, possibly with some reduction gearing.  The gears are definitely designed for flow rather than pressure and I can’t see a way to remove the drive piece from the motor without damaging anything. It seems firmly pressed or bonded in place. I will make my own pump using 24T MOD 0.5 brass gears and a Portescap 28mm motor from the bits box.

The body is a piece of 20mm square aluminium, drilled 11.5mm and reamed 12mm. There are M5x0.5 threaded holes for the two delivery valves and the fuel inlet. I then cut a 1.5 x 0.7mm groove for the O ring that will seal the sleeve to the body. At the other end the O ring groove is in the sleeve to allow it to be assembled without shredding the O ring on the ports.

[Roger B]

Next up was the first attempt at the three metering components. These are all from 2mm silver steel. For this first trial I am not hardening and lapping them.

The fixed stop and the control stop were turned down to 1.5mm for the appropriate lengths and the end of the fixed stop was taped M1.4 for a fixing screw.

[55fairlane]

Watching this with great interest,  I spent a lot of time at Kinsler fuel injection (Troy Michigan), I raced hemi powered cars, and they were motivated by Hilborn mechanical fuel injection, so I needed to learn to meter alcohol.  We were drag racing,  the Cuda made a mere 900hp (big big horsepower in its day) to 3000 plus on nitro methane  for the digger....mechanical fuel injection will build rpm faster then super charger, and doesn't rob near the power off the engine.   

Turned several carburetor intake manifold to mechanical fuel injection manifold no one made a great manifold for small Fords......

...do you need a vapor separator catch can ? Or can you you simply return by passed fuel straight back to the tank? What are you doing for a high speed by-pass ? Same with low speed by-pass? Gonna use the high speed by-pass as a rev limiter?  How are you calculating the leanth of the air horn (bell on top of the injection stack)?

I'm gonna have to dig out all my books and information to brush up on Lucas metering............if memory serves me right in late 70's or early 80's USAC racing , you ran carburetors and alcohol.......someone showed up with a Ford , Lucas metering on gasoline,  and wooped the track! USAC outlawed gasoline and mechanical fuel injection.....

Loving this build!

[Vixen]

Hello Roger.

Still following closely.   

Mike

[steamer]

Hello Roger.

Still following closely.   

Mike

Absolutely!!!