After reviewing my activities with the Soul Survivor last week, this week we’ll take a closer look at the engine swap. The car originally came with a 109 horsepower 2.8 liter Cologne V-6 with a carburetor, and I’ve upgraded it to a 150 horsepower fuel injected V-6 out of a Merkur Scorpio (I acquired the engine and many spare parts by buying a Scorpio for $500). As I explained at the time:
“All 2.9 Cologne V-6s were fuel injected, but I was concerned that the engine plenums used in the Ranger and Bronco II would not clear the Mustang’s hood. Since I used to own a Scorpio, I knew the induction system had a very low profile and would fit without question.”
There are two issues to any engine swap- Matching the block to the mounts and drive line, and connecting the ancillaries (fuel lines, throttle cable, electrical system, exhaust and cooling). Since the 2.9 and 2.8 share the same block, for my swap the engine mounts and drive line were a bolt up proposition.
Another issue is the clutch linkage- Many engine swaps languish behind the shop due to clutch linkage issues.
This is NOT an issue on the Soul Survivor- Since my car uses the factory bell housing, throw out bearing, and clutch cable, I’m assured reliable and smooth clutch action any time I step on the clutch pedal.
I had very few problems matching the external connections, but I did fight with the vehicle’s oil system for several weeks, and also had issues with frame rail clearance for the alternator and exhaust system. This week, I’ll cover the straightforward modifications, and then cover these headaches next week.
First up is the fuel injection system, which breaks into two topics- Electrical and fuel.
The electrical system was very straightforward, as I used the factory PCM (EEC-IV- Ford’s fourth generation system) and wiring. I reused the Scorpio wire harness, and since most system components and sensors were attached to the motor, I only had to connect the Mustang’s power feed to the harness, attach the harness grounds to the vehicle frame, and route the harness to the PCM mounted above the passenger’s footwell.
The Scorpio Powertrain Control Module was designed for use with an automatic transmission. I’d performed a manual transmission swap on a Scorpio back in 2000, and discovered this PCM had poor driveability when mated to a manual transmission. To address this issue, I changed over to a 2.9 Ranger 5 speed manual PCM (a “plug and Play” modification). My first test drive confirmed the Ranger computer solved my drivability problem.
To supply fuel, I needed a high pressure pump on the feed side, and a return line from the pressure regulator to the fuel tank. Ideally, the high pressure pump should be inside the fuel tank, with baffles to prevent sloshing while going around corners or tackling hills.
The Mustang II tank would not accept an in-tank pump without major modification, but I was able to re-use the existing metal fuel lines. Factory lines are always the preferred choice, since they are engineered to fit the vehicle, minimizing the likelihood of a fuel spill in an accident, and preventing damage from chassis vibration.
Instead of an intake fuel pump, I mounted a high pressure fuel pump at the fuel tank outlet. This approach has worked for the most part, but the pump did overheat while driving through Las Vegas, and occasionally sucks air when the fuel level drops. I’ve developed a fix for both issues, which I’ll review in the future.
The cooling system changes reflected the minor differences between the two engines. On the 2.9, Ford moved the thermostat from the lower radiator hose to the top of engine, but I found upper and lower hoses that worked with minor modifications (From a ’79 Mustang with the 2.8 as I recall).
The Scorpio engine had a bad fan clutch, which also placed the fan outside the radiator shroud. To solve this, I acquired a (longer) clutch and fan assembly from a junkyard Ranger. This gave me a working clutch and also positioned the fan correctly, improving cooling performance.
I also used Gates “Power Grip” hose clamps on the radiator and heater hoses. During installation, these thermoplastic bands fit over the hose at the hose barb, then a heat gun shrinks the clamp and locks the hose onto the fitting.
This design applies pressure perfectly around the hose diameter, and give me a very clean look after installation. Since they are single-use parts, some people don’t like these clamps. However, they have additional benefits, including the fact that they won’t deform the thin wall fittings on radiators or heater cores.
I chose corrugated water heater connectors to connect the engine to the heater core. The tubes are made of stainless steel, and this approach allows me to disconnect the heater lines without cutting off the Gates hose clamps.
They also have a nice bright finish, adding a little “bling” to my engine bay.
Speaking of bling, the 2.9 Scorpio upper intake plenum looks rather plain as delivered from the factory, but it does have the letters “EFI” and some nice ribs built into the casting. I also found some ’70’s vintage aftermarket Cologne V-6 valve covers with similar ribbing.
After many hours at the polishing bench, and a few coats of black paint for contrast, I ended up with a very attractive engine. I’ve been driving this upgraded engine package for about three and a half years, and it’s proven to be very reliable, with 1990’s performance in a 1970’s package.
Check back next week, when I highlight the problems encountered during this project, and the steps taken to address them.