Conversion of a 4/4 from Crossflow to Zetec

Background
With four-star petrol being withdrawn, it was time to consider the options with our 1979 4/4 1600 crossflow. I had always fancied a little more power but liked the narrow body of the 4/4. An article in Miscellany, describing how one owner had changed his 4/4 engine, set me thinking...
[ engine ]
Keeping an ear to the ground paid dividends when an 1800 Zetec turned up, from a Fiesta RS1800. This is the 130 PS variant, as used in the 4/4 circa 1994. It was decided to try and retain the standard injection, black box and all of the engine management system.
[ chassis]
I decided to change the gearbox for a 5-speed MT75, at the same time. This required alteration to the chassis. The shift mechanism was replaced with a Westfield Quickshift. This gives a far superior operation, with a short throw and positive feel. A specialist firm altered the prop shaft, once the final engine position was decided.
[ bay ]
A lightened flywheel, clutch and cover (for cable operation) were obtained from Dunnell Engineering. They also lowered and baffled the sump, giving extra ground clearance, helping to get the injection system under the standard bonnets.
[ nearside ]
With the engine in, the ECU and sensors were the next phase. Additional relays and fuse boxes were installed on the tool-box. Fortunately the MT75 has a road-speed sensor output. A K&N air filter was fitted on the cooler, induction side. The Ford ECU is a self-learning device and did not require re-mapping for our set up. The electric fuel pump (with safety cut out switch) and filter were also installed on this side.
[ offside ]
A combination of stainless tube and silicone hose provided the water connections. An electric fan, driven by a sensor added to the radiator, gives extra cooling, although an oil cooler was later installed. A Librands sports exhaust, without catalyst, was fitted.
The instruments were the final hurdle. The speedo and water temperature were no problem. The crossflow oil pressure fitting went straight into the block. This left the rev counter which would not work off the ECU output. Speedy Cables convert original instruments by adding a small circuit board. Zetec Tuning
Cams are crucial for 1800 Zetec tuning. The most effective way to raise the output of the 105 or 115 PS versions is to replace the cams. This is not an inexpensive operation (typically 300 for the cams alone) so, if you are switching your engine, it is worth while looking (and paying the extra) for a 130 PS spec engine to start with.
Impressions
The conversion has transformed this 4/4. The car is certainly much faster, with the extra power. There is more torque, a greater useable rev range and relaxed 5th gear cruising. On the track, the performance is now limited by the grip (or lack of) from the standard 165x15 tyres!

Regrets? ... None.


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