Ranger Biodiesel Swap - Air Intake

I wanted to reuse the original airbox and filter, as well as reinstall the original MAF and intake air sensors for later data acquisition (and to avoid throwing codes!).

Luckily, the airbox is on the same side as the intake manifold, so the design is greatly simplified. I used a 3" to 2" reducing 45-degree elbow, a tee-fitting with a 1" port for the temperature sensor, and a 90-degeree elbow to the engine, all connected with short lengths of 2" OD Steel pipe. 

The hardest part was the intake manifold adapter, which has an oval inlet. I machined the oval port on a piece of 1/8" steel plate, formed one end of a 2" steel pipe into a matching oval, welded the two together, and trimmed everything to fit under the hood.

 

Ranger Biodiesel Swap - Exhaust System

 The original exhaust system was unusable, so I needed to fabricate a new one from scratch. For simplicity and low-budget, it's made from AutoZone slip-fitting exhaust sections, welded together at most of the seams, and attached to the original VW collector.

I left one joint unwelded in the center of the pipe, so that I can experiment with different muffler and catalytic converters at a later date. For now, it will simply be a 1.75" unmuffled straight pipe.

VW Exhaust Collector

Down Pipe

Mocking up the system

Welding the exhaust seams.

The original engine in this truck was a V6, which used a pair of O2 sensors (one per bank). Rather than weld an extra sensor bung to the downpipe, I spliced a single sensor to provide electrical outputs to the pair of connectors.

After assembly and paint, I attached the rear of the exhaust to a hanger with a rubber isolator. I left this portion adjustable, to facilitate future exhaust upgrades.

Ranger Biodiesel Swap - Alternator Adapters

 To simplify wiring, I decided to mount the original Ford alternator on the VW engine. There's no tensioner pulley for the serpentine v-belt, so I fabricated a hinged adapter and tensioning rod.

The first version of the hinged adapter was made from billet aluminum. 

Next, I turned an aluminum v-belt pulley on my lathe, to match to profile of the original VW pulleys.

Finally, I bent a steel bracket that curves around the outside of the alternator and bolts to the engine block. With an 8mm socket cap bolt and fender washers, I made a tensioner that pulls the belt tight, rather than pushes.

After installing the engine, I discovered that the alternator was hitting the steering u-joint and needed to be rotated higher. The aluminum hinge was at its limit of travel, so I made a replacement out of steel that allowed better clearance.

Ranger Biodiesel Swap - Throttle Cable Adapter

Now that the engine is solidly located and installed, it's time to work through the smaller details. For the sake of simplicity and spare parts, I wanted to adapt the original throttle cable to the VW injection pump. 

The VW cable sleeve was round and the Ford sleeve is rectangular, so I carefully filed the retainer bracket until the Ford cable fit. The next step was the adapter between the cable end and the lever on the fuel injection pump.

My first attempt was a simple block, but I realized that the cable end would slightly rotate in the retaining hole, causing friction and wear.

I designed a second adapter, with a guide slot hand-filed with a partial radius. This radius will support the braided cable itself as the lever moves through its circular motion, without causing the cable end to move. This results in a smooth and repeatable throttle action.

 

Ranger Biodiesel Swap - Thermostat And Radiator Hoses

With the engine more-or-less in its final position, the next steps are wiring and plumbing the various accessories. I started with the cooling system.

Using some rough measurements, I searched through the molded coolant hoses on the back shelves at my local auto parts store, to find the right combinations of inner diameters, curves, and lengths. The hoses attached to the radiator have a 1.5" inner diameter, whereas the hoses attached to the engine have a 1.25" inner diameter. Therefore, it was necessary to use single-piece stepped hose adapters, which I found on Amazon made from billet aluminum. The lower adapter also has a threaded port machined into the side, which I used for the heater core return hose (originally 1/8 NPT, bored out to 1/4 NPT). The final parts list consisted of:

Lower Hose

- Dayco 70989 Hose

- Dayco 71852 Hose

- ICT Billet Radiator Hose Barb Coupler with 1/8" NPT Port 1-1/4" to 1-1/2"

Upper Hose

- Continental 62968 Hose

- Continental 61782 Hose

- ICT Billet Radiator Hose Barb Coupler 1-1/4" to 1-1/2"