Mangoletsi Throttle Linkage

My approach to the restoration has been to keep things as standard and drive the car for a while, before making any modifications. The two main areas that I have deviated from this are; fitting an EDIS Megajolt electronic ignition system and using the Mangoletsi cable throttle linkage.

The standard throttle has an inherent amount of free play due to the numerous joints in the linkage. The decision to fit the Mangoletsi throttle was aimed at improving the throttle response by removing this play and was based on the views of numerous forum members. My slight reservation was the appearance of the cables within the engine bay, as they arc from the pedal housing to the inlet manifold.

Mangoletsi cable throttle kit

The kit was ordered from SNG Barratt before the engine had been installed in the car which made the initial fitting of the components much easier! Although the completed inlet manifold and carburettors would be removed as a completed unit to fit the engine from underneath.

The kits are very well made and came in four clearly marked bags, and with detailed instructions. Most of the components are already fully assembled and pre-set so the installation is very straightforward.

The system uses twins cables to balance the load on the levers, providing a smoother operation, and the cables were the only components that would have to wait until the engine was in situ.

The first bag contained a linkage plate and gaskets which simply fits between the carburettors and the inlet manifold. The gaskets used are thinner than standard to compensate for the added thickness of the plate. The carburettors are re-fitted and then the kit’s spring carrier bracket is attached to the linkage plate. Pre-fitted to the bracket are the adjustable outer cable abutments which would be adjusted during the final set up.

Thinner gaskets are used	Carburettor linkage plate

The carburettor’s standard SU throttle levers are replaced with ‘aircraft standard’ rose jointed levers, which have a quality feel to them, with a smooth and precise operation and no free play. The top rose joints are bolted to their respective levers on the shaft of the linkage plate. The only slightly fiddly part of the installation was synchronising the operation of the three carburettors. Although this was adequately covered in the instructions.

The kit’s spring carrier	Hex adjustment for rose jointed tie rod

A jig plate is used to lock the linkage to a datum position to fit the rear rose joint tie rod, which has been pre-set to a length of 21mm. The front and centre tie rods are then fitted in turn and their lengths adjusted so the brass throttle plates all close at the same time.

An entirely new pedal housing is also included which allows the pedal position and length of travel to be adjusted to suit. Although it has been left at the pre-set 40mm of travel for now. Any fine adjustments will have to wait until the car is completed.

I should have been expecting it …. I then hit a major snag. It was all going far too well up to that point!!

When the pedal was depressed, the top of the pedal lever fouled the starter relay mounted on the bulkhead. I thought the relay may have been incorrectly mounted but old photos confirmed the relay was in the correct position. The new pedal housing was the problem!

Even mounting the relay on the wrong side of the bracket didn’t solve the problem. In fact it made it worse! The lever now just hit the relay bracket instead but also, it was then impossible to connect the wires to the relay. The reservoir bottles were in the way!

Early photo confirms correct position	Relay mounted the wrong side	But now the accelerator just hit the bracket

In the end I contacted John Mangoletsi to find out why I was having problems fitting it. He was most helpful and was unaware of this issue, as it had not be reported to them before. A different kit is produced for 3.8 and 4.2 models and each has to be compatible with all the in-flight changes that Jaguar made at the factory.

It soon dawned on me that the relay position had changed right at the end of the S2 production run, as I found out when my wiring puzzle was solved. The relay moved to the engine bay bulkhead with the introduction of the ballast resistor. An additional relay loom was also added to wire in the relay in its new position. A loom that took ages to track down.

John Mangoletsi indicated that the kits were specifically designed to fit all the models and were sold as such. He kindly offered to visit to see the issue in person and come up with a revised solution for mounting the relay. One that could then be offered for the (few) cars which had a ballast resistor.

Starter relay relocated to its
original pre-Ballast resistor
position under the A-post

At this stage I realised I was being a bit dim! I already had the solution: the other change I was making was the EDIS Megajolt ignition system which removed the need for a coil and therefore the ballast resistor.

I could simply move the relay back to its original position on the bulkhead underneath the A-post and do away with the additional relay loom completely. Problem solved!

The final tasks were to connect up the cables once the engine was in place and tidy up the empty bulhead holes for the original linkage. I chose to fit socket head button screws rather than blanking grommets.

In summary, the Mangoletsi throttle cable linkage is a quality bit of kit and could probably be installed in a day or a lazy weekend. I will have to make a point of driving a standard car so I can feel the difference to make sure it was worth it!