SU HIF44 Carburettor Installation #3

Throttle Pedal Bracket and Cable Installation

Preamble

In this post, I’ll focus on connecting the throttle cable to the new carb. This requires some work to the throttle pedal and footwell.

The SU throttle is cable controlled, as opposed to the rod and bell crank arrangement of the original Solex. To convert the operations to cable, HNJ Engineering supply a bracket that needs to be bolted to the throttle pedal in the cab. A 13mm hole needs to be drilled in the top of the footwell to accommodate the new cable end.

As mentioned in an earlier post, the cable supplied by HNJ is made in-house by then but only for RHD models, so I’m using a similar product from a LHD 2.5 litre petrol 90… although the quality doesn’t come close to that supplied by HNJ. Part number below.

The Parts

Throttle pedal bracket: HNJ2286-005
3xM5 cap crews (incl nuts and washers)
Throttle cable: NTC2087
Throttle cable nut: NT112041L
13mm HSS drill bit
Callipers (for measuring the cable pull and getting the bracket in the right place)

Installation

This is the pedal bracket as supply by HNJ Engineering. I painted it black so it’s less obvious in the cab

First, the throttle cable needs to be installed into the footwell and carb. Once complete, the maximum amount of cable pull needs to be established. This is important. Without this, the correct position for the bracket on the pedal can’t be determined properly.

13mm hole drilled in the top of the foot box (black dot)

Throttle cable installed in the footwell

Install the other end of the cable to the throttle cam and mark the cable where it passes into the cover. Then rotate the throttle cam from fully closed to fully open and mark the cable in the same relative location.

Remove the cable and measure between the two marks. I now know the max cable pull from idle to full throttle is 40mm. This figure can now be used to determine the correct location of the throttle pedal bracket.

Throttle pedal bracket and throttle pedal

With some trial and error a good position is found that will give the required 40mm travel and more

Throttle pedal drilled and bracket mounted

Back on the vehicle, the end of the throttle cable is attached (sorry, not the best picture)

I did actually have to shorten the outer cable as it was still way too long. With enough force the outer can be pulled free of the crimped metal end. The outer was cut down to the required length, the hexagonal crimp drilled out to 5.5mm (the dia as the outer) and the two bonded back together. A short length of shrink wrap finished the job off nicely.