We're transforming a 1960 Ford Falcon into a long-distance cruiser. We've dubbed this car the Vagabond Falcon, and it currently has a small 2.4 liter straight-six. That's not enough power. The idea is to swap in a 5.0 V8 out of a Thunderbird and keep the entire car looking and functioning as period as possible. That includes the engine and internals. This is way harder than it sounds, especially making the 1993 5.0 V8 behave like it's an engine from the 1960s.
Our 5.0L V8 came out of a 1993 Ford Thunderbird that met its demise in a front-end crash with just 70,000 miles on the clock. The engine and transmission survived unharmed, but the rest of the car was totaled. The car was then used by a Virginia fire department as a Jaws of Life practice vehicle. After the Thunderbird was sliced up more than chipped beef, a fan of RCR asked if we wanted the engine and transmission for cheap. Of course we did.
I felt romantic. We were saving an engine that would otherwise have met a pitiful end in a scrapyard. We would rebuild it. We would return this Ford 302 V8 to its carbureted and fully mechanical halcyon days of the late 1960s. Yes! Yes! Yes! We would remove the EGR (exhaust gas re-circulation), toss the intake plenum for a carbureted intake, and go back to a mechanical fuel pump.
That mechanical fuel pump was the one change that opened a Pandora's box of mechanical problems.
In 1993, the Ford 5.0-liter used an electric fuel pump because it could push the 40, 50, or 60 psi needed to pressurize the fuel rails and fuel injectors. But we're going to fuel this engine with a carburetor that only needs about 5 psi. Period-correct carbureted engines do not use electric fuel pumps because too much pressure can overfill the float bowls and blow the delicate little brass and rubber fuel valves. Yes, fuel pressure regulators solve this problem. Yes, modern mechanical fuel pumps need regulators too because they are more efficient (our mechanical pump runs at 8 psi). But it's also a style thing. Running a mechanical fuel pump allows you to make friends with all those old-timey purists and their big mustaches. You instantly become a member of a very pedantic club.
Electric fuel pumps also must have fuel in them to run safely. Gasoline acts as the lubricant for an electric fuel pump. If you run your tank completely dry and attempt to "drive on fumes," you will burn out an electric pump very fast. Mechanical fuel pumps are bolted to the engine and get their lubrication from the engine oil. Running them dry won't hurt them.
A mechanical fuel pump operates by the same principle as an old-fashioned, that you would see on a farm or in a Dixiesploitation movie like "God's Little Acre."
A moving plunger and a free valve create a momentary vacuum on the upstroke that pulls water (or in a car's case, fuel) up from a source. On a car, the "arm" of the pump is operated by an extra lobe bolted onto the camshaft outside of the cylinder block. As long as the engine turns, the arm of the pump moves and fuel flows. The faster the engine turns, the faster the cam and arm moves, and the more fuel it pulls. A mechanical pump's GPH rate (gallons per hour) is self-regulating. Brilliant!
"Why over do it?" That was my thinking. After all, period V8's ran mechanical fuel pumps and they work fine, why would this be any different? Don't fix what ain't broken. But converting a modern engine to a mechanical fuel supply is, apparently, far from easy.
In order to mount a mechanical pump to the 1993 5.0, we needed a timing cover, which has a port and mounting location for it. Bruce Henn, our builder/guide for Operation Vagabond Falcon, had a spare timing cover from a 1968 Mustang that had a pass-through port for a mechanical pump. It bolted onto our 1993 engine block just fine after a little sanding.
But, oh no!
A 1993 water pump doesn't fit a 1968 timing cover. The mounting surfaces were a different shape and the water flow was reversed. That meant we needed an old-style water pump for a 1968 Ford 302. Fine. We got the right water pump and that bolted on.
But, oh no!
A 1968 water pump shaft is too long. It stuck out longer than the end of the 1993 harmonic balancer. That meant the water pump pulley would not line up with the crankshaft pulley. I needed to buy offset aftermarket pulleys to match the difference in distance. I bought the pulleys and they bolted on just fine.
But, oh no!
The aftermarket pulleys had too much offset. Now, the formerly too long water-pump shaft pulley was too short. It had to move forward. We needed a spacer to move the pulley out about 11mm, which we bought.
But, oh no!
The aluminum spacer was too big. Now the water pulley is too far forward. I felt like Sisyphus. I draw a line on the spacer 11mm from its edge, and take it to the band saw to make it the right size.
But, oh no!
I screwed up. I cut crooked. I put the aftermarket pulley, with my self-cut spacer, onto the water pump and spun the pulley . . . the pulley wobbled. You can't have a wobbling pulley spinning at a redline of 5500 rpm. You could shake the timing cover off.
I took the spacer, a digital caliper, and a die grinder to a bench vice. I drew divisions on the spacer like pizza slices. Along the edge of the spacer, I measured at regular intervals and wrote the thickness directly on the spacer with a black marker: 11.66 mm, 11.43 mm, 11.22 mm 11.08 mm, 11.01mm, 11.09mm, 11.19mm, 11.29mm, 11.5mm. I saw where the spacer was thick and where it was thin. Starting at the thickest point, I carefully ground down each section of the spacer. I stopped and re-measured. This took an entire workday. I moved slowly and kept measuring and grinding and measuring and grinding until at last the spacer was exactly 11.01mm thick all around.
I slid the spacer on the water pump, bolted the water pump over the spacer, held my breath, and spun the pulley . . . no wobbles. I felt amazing! I felt like I won the spelling bee!
I've built a YouTube show. I've made a lot of friends. I've met some famous people. I now write for Road & Track. But, let me tell you, placing that pulley on the spacer, bolting it to the water pump, and watching it spin true with no wobble , well, that thrill and wave of satisfaction ranks up there with all we've done together.
Yes, if you change one thing on an engine, you change many other things. This was a silly idea, trying to strive for some kind of hipster authenticity with a mechanical fuel pump. At least we now have, at an internal level, a motor that is unique to us. A hodgepodge of Ford parts that never played together before.
Still, if you are trying to make a modern engine feel old, stick with an electric fuel pump. You'll save yourself a week of work.