Fuel & Exhaust System
The electric Fuel Pump is located underneath the vehicle, on the nearside rear sub-frame. It is secured to a special bracket, which is flexibly mounted to the sub-frame, using ‘cotton reel' type mounts. These two mounts can perish and de-laminate, resulting in the fuel pump hanging from its fuel pipes!
The Fuel Pressure Regulator is located in the engine bay, and is secured to the left of the front bulkhead. Flexible rubber hoses connect the regulator to the metal fuel pipes that run the length of the vehicle and these short hoses must be in good condition and secured at each end with the correct clips. The regulator is preset during manufacture and the upper adjusting screw and locknut should be free from any signs of being tampered with.
The carburettor is the SU HIF44 but, despite its external appearance, is a special sealed version of this model. Because of the positive pressure in the inlet manifold during turbo boost, it is fitted with special shaft seals and is pressure tested during manufacture. Check that the model number on the aluminium plate attached to the top of the float chamber is FZX 1435. If the label is missing or the number is different, this indicates that a similar but unsealed carburettor has been fitted from a standard 1275cc engine.
WARNING: Using an incorrect type of carburettor can be dangerous, as fuel at high pressure will be sprayed over the hot exhaust manifold if the unsealed shaft develops a leak.
A fibreglass heat shield, coated in aluminium reflective paint, should be fitted to the underside of the carburettor. Without this shield fitted, or if the coating is in poor condition, fuel vaporisation occurs, resulting in poor starting whilst the engine is hot.
|An ‘anti-run on' valve mounted horizontally to the top plate of the brake servo or vertically to the adjacent inner wing, is connected to the vent pipe of the HIF 44. This item is energised by the ignition supply, thus closing the vent, but opens when the ignition supply is removed, effectively venting the inlet manifold to atmosphere and thus stopping any over-run. With light finger pressure on the valve body, it can be felt to close as the ignition is set to position II. The vertical mounting position is preferred, as gravity then aids opening of the valve. If the valve does not close, the engine will start and idle, but any attempt to drive the car causes a massive loss of power, as the inlet manifold remains vented to atmosphere. If these symptoms are encountered, the vent pipe can be pinched or plugged with a suitable bolt to check if a defective valve is the cause of this problem.|
The Bulkhead at the rear of the engine incorporates a ‘turbo box' to provide room for the body of the turbocharger. This item was fitted during conversion from the ‘City and consists of a heavy gauge steel enclosure welded into position in the front bulkhead. Its top edge is located flush with the top surface of the box-section and a heavy gauge steel plate forms a new top section to the cross-member. Because of the intense heat generated by the turbo, the whole bulkhead area to its rear, including the inside surface of the turbo box, is covered with aluminium faced, heat resisting fabric. Ideally, this material should be in good condition. It is readily available but very expensive to replace. Because this area is covered, it can trap any rainwater running into the engine bay from the rear of the bonnet. In consequence the metal forming the turbo box can be heavily rusted and it has been known to rust through, despite the heavy gauge metal. Careful prodding in this area with a suitable screwdriver, without damaging the heat resistant fabric, will show up any weakness in the metal.
In addition to the turbo box, the speedometer cable and any adjacent piping should be wrapped with the heat-resisting fabric.
The exhaust down pipe connects to the turbocharger outlet flange and incorporates a ‘ball joint' type coupling at the transition to the horizontal. Original front pipes are no longer manufactured, but suitable items are available from several Mini aftermarket suppliers. Ensure that the fitted pipe is secure, in good condition, is clear of the rod type gear-change linkage and does not foul the underside of the body at any point.
A small amount of oil smoke from the exhaust is to be expected on initial starting, due to oil leaking around the turbocharger spindle when stationary. Any excessive or prolonged exhaust smoke when running may indicate turbo seal failure. This would require the unit be reconditioned.