Modifying the Westfield Cooling System.
Overview
Photograph, courtesy of Tim Hoverd
The modification of the Westfield cooling system looks straightforward at first glance. “Tee Piece solutions are quick and easy to implement (See photograph right) but suffer from excessive expansion and possible overflow of the header tank. This is probably caused by coolant from the thermostat bypass and heater coolant competing to use the same pipe. The pipe diameter is insufficient to sustain the volume and flow rate required.
The provision of a separate bypass pipe, as used in the Ford Mondeo, is the recommended solution. This avoids the excessive expansion problem. The relative diameter of the thermostat bypass pipe, to the alloy pipe running from the thermostat outlet to the radiator top hose is important. We recommend 16mm, ½” bore pipe as giving adequate flow before the thermostat opens and minimal bleed across the engine once the thermostat is open. Expansion in to the header tank will still take place but this is normal, and it should not overflow. Any excess coolant will be ducted via the overflow pipe back to the radiator.
The principle of modifying the Westfield cooling system is the same for non-ducted and ducted nose. Ford 2.0Ltr and 1800cc variants. There are detail differences but two common alterations need to be accomplished on each.
1. Connect a new bypass pipe from the thermostat housing to the Radiator bottom hose
2. Blank off the old bypass connection in the alloy pipe to the top hose.
Zetec 2.0L Water Pump Inlet
The simplest solution would be to replace the water pump inlet pipe with one that has a branch in it, to permit connection of the bypass pipe. However it is not possible to implement a single solution, due to differences in the angle of the water pump inlet on 1800 cc and 2.0 Litre engines. The photograph (left) shows that the inlet on the 2.0 Litre Zetec is angled back towards the exhaust system. Despite extensive research no suitable replacement for the water pump inlet pipe could readily be found.
Photograph, Courtesy of Steve Richards
The water pump inlet on the 1800 is at right angles to the engine cylinder block, and a modified pipe from a Mondeo can be used, as shown on the right. For this reason the modification of the cooling system is sectioned in to two. - Ford Zetec 2.0 litre, ducted and non-ducted nose, using a modified Alloy pipe.
- Ford 1800 Zetec, ducted and non-ducted nose, using a modified Mondeo Pipe.
Zetec Water Pumps
Westfield Auxilliary Drive Belt
Diagram, Courtesy of Haynes Publishing
The Ford Mondeo auxiliary drive (serpentine) belt drives the water pump (7), power steering (1), air conditioning compressor (5) and Alternator (3) from the crankshaft pulley (6) as show in the diagram above right. From the Diagram if the crankshaft pulley rotates clockwise, the water pump rotates anti-clockwise. Westfield recommends that 2.0L Zetec Engine owners replace the single “Vee” the water pump pulley for a multi “Vee” pulley as used on Zetec 1800 Engines. The Auxiliary drive belt is then connected as shown in the photograph, above left. On the Westfield system the crankshaft and water pump rotate in the same direction. The implication is that the water pump in the Westfield 2.0 Zetec system is running backwards. Running the pump in reverse will reduce the efficiency of the pump. Operationally this seems to make little difference
The diagram left, shows a typical water pump and explains why the pump will work in either direction. The inlet is to the centre of the impeller and the blades push the coolant to the outlet, regardless of rotation. Impeller design means it will be more efficient when rotated in the correct direction.
Owners may feel that in any event they would like to correct this situation. The Zetec water pump is replaceable as a complete unit. The solution is to replace the 2.0 Zetec water pump with an 1800 Zetec water pump.
Zetec owners who replace the 2.0 Zetec water pump with an 1800 Zetec water pump can use the modified Mondeo bottom hose solution.
Modifying the Westfield Ford Zetec 2.0 Litre Cooling System.
Ford Zetec 2.0L Non-Ducted Nose Modifications
The schematic diagram shows a new junction welded in to the alloy pipe running between the radiator bottom hose and the water pump inlet. This junction is connected via a new alloy pipe to thermostat housing bypass outlet. The new junctions and pipe work have anti blow off ends formed by running a weld around the circumference of the pipe.
The heater connections are not modified
(Click on the diagram for a full size picture)
Radiator bottom hose connections (Modified)
The diagram, above left, shows the modified alloy pipe. It is not to scale and is dimensionless to allow the modification of the pipe to suit the vehicle. On our car there was sufficient room to weld a second junction to the pipe, leaving suitable clearances to fit the rubber hoses. Anti blow off ridges were formed by welding around the circumference of the pipe (Click on the diagram for a full size picture)
The photograph, above right, shows the modified bottom hose alloy pipe on situ,. The right hand junction is connected the heater and the left hand junction is connected to the new bypass pipe.
A suitable bypass pipe can be manufactured to the approximate dimensions as above. Made from 16mm alloy or copper tube with a bend formed at each end. The downward end, which connects to the modified alloy bottom pipe is formed at 15˚ from the vertical or 75˚ with respect to the horizontal junction, which connects to the thermostat housing. Anti blow off ridges can be made by running a weld round the circumference of the pipe. If copper pipe is used suitable bends can be made from “Yorkshire” solder fittings (Click on the diagram for a full size picture)
The photograph shows the new bypass pipe connected to the modified bottom hose alloy pipe and routed alongside the heater pipe. The bypass pipe and heater pipe are secured together, at regular intervals, using pipe / wiring clips available from Vehicle Wiring Products.
The Diagram (above) shows the Radiator top hose connections modified. An alloy pipe, “J”, from the radiator top hose to the main thermostat-housing outlet this pipe has the junction that was connected to the thermostat bypass. This must be blanked off and sealed. This pipe also contains the thermostatic switch for the fan. If you have a “red top” switch Ford FINIS No: 7001614, replace it with an “orange top” switch Ford Finis No: 7001611 (Click on the diagram for a full size picture)
The photograph above right shows the connections to the Thermostat housing. The thermostatic switch (blue plug) can be seen, fitted in to the pipe from the main thermostat-housing outlet. Beneath this pipe is the rubber hose connecting the new bypass pipe to the thermostat bypass outlet. The blanked off connection in the main pipe was made using a ½” BSP adapter and an M10 Bolt. The pipe was tapped to ¼ ”BSP thread and the adapter was, internally, tapped to match the M10 bolt. The ¼ ” BSP adapter was wrapped in PTFE tape to seal it and screwed in to the pipe. The M10 Bolt was similarly wrapped in PTFE tape and screwed in to the adapter. This arrangement has proved watertight
The Photograph (above left) shows the coolant pipe running down the Left had side of the body. The alloy pipes are fastened together using pipe clips to provide a neat and secure installation. ((Click on the diagram for a full size picture)
Diagram 48 (above right) shows that the heater connections are unmodified. However due to the substantially smaller Westfield expansion tank, to ensure that there is sufficient expansion space in the header tank, the system should be filled to half way between the minimum and maximum marks on the tank
Ford 2.0 L Zetec Ducted Nose, Modifications.
The modification of the ducted nose is the same as non-ducted nose. Just the layout detail is different, caused by the radiator being fixed to the nose cone and not the chassis. The diagram (above left) shows the bottom hose connections with a new junction welded to the alloy pipe as before and connected to the water pump inlet. A rubber hose connects to the new junction to the alloy bypass pipe. Which is connected at the opposite end, to the thermostat housing bypass outlet (Click on the diagram for a full size picture)
Similar to the non ducted nose installation the alloy pipe connecting the Radiator top hose and the main thermostat housing outlet has the redundant junction, formerly used for connecting to the thermostat bypass (above right). This must be blanked off and sealed
The Thermostatic switch for the fan is mounted in the radiator. If you have a “red top” switch Ford FINIS No: 7001614, replace it with an “orange top” switch Ford Finis No: 7001611 for normal fan operation. (Click on the diagram for a full size picture)
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