Home 2000 2400Sd 2300 2600 3500 Vitesse Buyersguide Rover Specials Technical Contact
© www.roversd1.info
SU Carburetors
On this page an explenation how to dismantle the SU HIF44 carburetor used in both 6 cilinder as v8 models.
HIF44 Carburetter: Inspection - Reassembly   

Step 1

(a) Examine the throttle spindle and its bearings in the carburetter body; check for any excessive play, and renew any parts as necessary. (b) Examine the float needle, seating and filter where fitted for damage, contamniation and excessive wear; renew if necessary. (c) Examine all rubber seals and '0' rings for any damage or deterioration; renew as necessary. Thecover-plate sealing ring and starter '0' ring must be renewed. (d) Check condition of all fibre washers and gaskets; renew as necessary.  

Step 2

(a) Examine the carburetter bodyfor cracks and damage, and for security of the brass connections and the piston key. (b) Clean the inside of the suction chamber and the piston rod guide with fuel or methylated spirit (denatured alcohol) and wipe dry. Abrasives must not be used. (c) Examine the suction chamber and piston for damage and signs of scoring.

Step 3

Ball bearing suction chambers. Check that all the balls are in the piston ball race (2 rows, 6 per row). Fit the piston into the suction chamber, without the damper and spring, hold the assembly in a horizontal position and spin the piston. The piston should spin freely in the suction chamber without any tendency to stick.

Step 4

The following timing check applies onlyto standard suction chambers and need only be carried out if the cause of the carburetter malfunction which necessitated the dismantling has not been located. (a) Temporarily plug the piston transfer holes (1). (b) Fit the piston into the chamber without its spring (2). (c) Fit a nut and screw, with a large flat washer under the nut, into one of the suction chamber fixing holes, positioning the washer so that it overlaps chamber bore (3). (d) Fit the damper and washer (4). Check that the piston is fully home in the chamber, invert the assembly to allow the chamber to fall away until the piston contacts the washer (5). (e) Check the time taken for the chamber to fall the full extent of the piston travel. For carburetters 38.0 mm (1.5 in) to 47.6 mm (1 7/8 in) bore, the time taken should be 5 to 7 seconds. (f) If the times are exceeded check the piston and chamber for presence of oil, foreign matter and damage. If after re-checking the time is still not within these limits, renew the suction chamber assembly. HIF Type Carburetter: Reassembly Reassembly by reversing the procedure used to dismantle the carburetter, noting the following: (a) Ensure that the throttle disc is fitted in its original position. (b) New throttle disc retaining screws must be used when refitting the disc. Ensure that the throttle disc is correctly positioned and closes correctly before tightening the retaining screws. Spread the split ends of the screws sufficiently to prevent turning. (c) Position the throttle spindle end seals just below the spindle housing flange. (d) The starter unit valve is fitted with the cut-out towards the top retaining screw hole and its retaining plate is positioned with the slotted flange towards the throttle spindle. Apply a smear of oil to the starter '0' ring prior to assembly, the starter should then enter the carburetter body with ease. If force has to be used this will invariably result in damage to the '0' ring. (e) When fitting the jet assembly to the adjusting lever ensure that the jet head moves freely in the bi-metal cut-out. (f) After fitting the float and valve, invert the carburetter so that the needle valve is held in the shut position by the weight of the float only. Check that the point indicated on the float (see illustration) is 10 +/- 0.5 mm (0.04 +/- 0.02 in) below the level of the float chamber face (see illustration). Then adjust the float position by carefully bending the brass pad. Check that the float pivots correctly about the spindle. (g) Ensure that the needle guide fitted gives the needle bias in the required sense (either toward throttle disc or toward air cleaner). Before tightening the retaining screw, check that the needle guide is in its correct position relative to the piston face, eitherflush with the bottom of the piston on standard pistons or flush with the recess on recessed pistons. (h) Ball bearing suction chambers. To prevent piston spring from being 'wound up' during reassembly, temporarily fit the piston and suction chamber, less the piston spring, to the body and pencil mark their relative positions to each other. Fit the spring to the piston, hold the suction chamber above the piston, align the pencil marks and lower the chamber over the spring and piston. It is essential that the bearing retention clip (early type) or the bearing retention circlip (later type) is correctly fitted.
SU Carburetors
On this page an explenation how to dismantle the SU HIF44 carburetor used in both 6 cilinder as v8 models.
HIF44 Carburetter: Inspection - Reassembly   

Step 1

(a) Examine the throttle spindle and its bearings in the carburetter body; check for any excessive play, and renew any parts as necessary. (b) Examine the float needle, seating and filter where fitted for damage, contamniation and excessive wear; renew if necessary. (c) Examine all rubber seals and '0' rings for any damage or deterioration; renew as necessary. Thecover-plate sealing ring and starter '0' ring must be renewed. (d) Check condition of all fibre washers and gaskets; renew as necessary.  

Step 2

(a) Examine the carburetter bodyfor cracks and damage, and for security of the brass connections and the piston key. (b) Clean the inside of the suction chamber and the piston rod guide with fuel or methylated spirit (denatured alcohol) and wipe dry. Abrasives must not be used. (c) Examine the suction chamber and piston for damage and signs of scoring.

Step 3

Ball bearing suction chambers. Check that all the balls are in the piston ball race (2 rows, 6 per row). Fit the piston into the suction chamber, without the damper and spring, hold the assembly in a horizontal position and spin the piston. The piston should spin freely in the suction chamber without any tendency to stick.

Step 4

The following timing check applies onlyto standard suction chambers and need only be carried out if the cause of the carburetter malfunction which necessitated the dismantling has not been located. (a) Temporarily plug the piston transfer holes (1). (b) Fit the piston into the chamber without its spring (2). (c) Fit a nut and screw, with a large flat washer under the nut, into one of the suction chamber fixing holes, positioning the washer so that it overlaps chamber bore (3). (d) Fit the damper and washer (4). Check that the piston is fully home in the chamber, invert the assembly to allow the chamber to fall away until the piston contacts the washer (5). (e) Check the time taken for the chamber to fall the full extent of the piston travel. For carburetters 38.0 mm (1.5 in) to 47.6 mm (1 7/8 in) bore, the time taken should be 5 to 7 seconds. (f) If the times are exceeded check the piston and chamber for presence of oil, foreign matter and damage. If after re-checking the time is still not within these limits, renew the suction chamber assembly. HIF Type Carburetter: Reassembly Reassembly by reversing the procedure used to dismantle the carburetter, noting the following: (a) Ensure that the throttle disc is fitted in its original position. (b) New throttle disc retaining screws must be used when refitting the disc. Ensure that the throttle disc is correctly positioned and closes correctly before tightening the retaining screws. Spread the split ends of the screws sufficiently to prevent turning. (c) Position the throttle spindle end seals just below the spindle housing flange. (d) The starter unit valve is fitted with the cut-out towards the top retaining screw hole and its retaining plate is positioned with the slotted flange towards the throttle spindle. Apply a smear of oil to the starter '0' ring prior to assembly, the starter should then enter the carburetter body with ease. If force has to be used this will invariably result in damage to the '0' ring. (e) When fitting the jet assembly to the adjusting lever ensure that the jet head moves freely in the bi-metal cut-out. (f) After fitting the float and valve, invert the carburetter so that the needle valve is held in the shut position by the weight of the float only. Check that the point indicated on the float (see illustration) is 10 +/- 0.5 mm (0.04 +/- 0.02 in) below the level of the float chamber face (see illustration). Then adjust the float position by carefully bending the brass pad. Check that the float pivots correctly about the spindle. (g) Ensure that the needle guide fitted gives the needle bias in the required sense (either toward throttle disc or toward air cleaner). Before tightening the retaining screw, check that the needle guide is in its correct position relative to the piston face, eitherflush with the bottom of the piston on standard pistons or flush with the recess on recessed pistons. (h) Ball bearing suction chambers. To prevent piston spring from being 'wound up' during reassembly, temporarily fit the piston and suction chamber, less the piston spring, to the body and pencil mark their relative positions to each other. Fit the spring to the piston, hold the suction chamber above the piston, align the pencil marks and lower the chamber over the spring and piston. It is essential that the bearing retention clip (early type) or the bearing retention circlip (later type) is correctly fitted.
Site Navigation