A: Before starting work, consider that you may wish at some stage to revert to the original twin carb Solex system. To this end, ensure that no permanent changes are made to exisiting components - e.g. - cutting the throttle cable to length, etc.

You will have to be prepared to make a few compromises to engineering integrity to complete the job.

At some stage in the proceedings, you will need to access the underside of the vehicle (front of engine bulkhead) so be sure your van is positioned correctly to receive rear axle stands before you disable the engine!

For clarity, the right-hand side of the vehicle is same side as No.1 cylinder.

To Begin
Disconnect the Battery.
Disconnect the power supply wire from the coil and carb.electrics.
Detach hose connections from the air cleaner.
Remove the air cleaner and filter air box.
Disconnect the fuel hoses at the carb. connections. Plug each securely.
Remove the throttle back-tension spring.
Release the throttle cable from the throttle-actuating arm.
Remove the advance-retard vacuum pipe from the left-hand carb.
Remove the balance pipes and central mounting plate. Be sure to replace the mounting plate screws to the crankcase.
Pull off the throttle ball joints at their lower ends.
Undo the four nuts securing the carbs. to induction manifolds.
Carefully recover each nut and washer.
Loosen the carbs, to allow removal of the actuating arm, keeping one finger over the right hand end of the arm to retain the plug and spring.
Remove with care each Solex carb. Hold in safe place and expel the retained petrol.
At this point it would be prudent to thoroughly clean the top of the engine, ensuring no debris enters the open manifolds.
Now remove the brake vacuum pipe flexible connectors from each manifold.
Clean around the base of each induction manifold, blow off any debris before removing these manifolds. (Make sure you recover all nuts and washers before attempting to move the manifolds). Carefully clean off the joint surfaces on each head, again ensuring no debris enters the engine via. the induction ports.
It is now time to place the rear of the car on suitable stands to gain access to the left rear.
Remove the left rear wheel.
Loosen the vacuum pipe clamp near the bulkhead.
(This would be a good time to adjust the clutch travel if required).
Back in the engine bay, undo the central clip holding the vacuum pipe and remove the assembly.
This completes the strip down. Tidy all removed parts into a safe place.

Assembly
Offer up each new induction manifold and ensure that they sit flat on the head. (Ideally the manifold mounting plates should already be surface ground to ensure a good seal).
Attach one induction manifold (finger tight) using plain steel nuts, and then offer up the central manifold block. The remaining induction manifold should then be positioned on its studs, and the assembly checked to ensure that both manifolds line up with the manifold block. With each pipe inserted in the manifold block, and the block uniformly positioned, there should be little or no tension on the port studs - in other words the manifold assembly should still sit squarely on their respective heads.
Now try the fitting again, but with the manifold gaskets in place.
DO NOT ATTEMPT TO PROCEED IF THE MANIFOLD ASSEMBLY DOES NOT ALIGN. If in any doubt abort the installation now, and consult your supplier.
Remove the manifold assembly, and fit the nylon brake vacuum pipe adaptor to the manifold block. This seems to be a taper fit, and may not screw right in.
Fit the four 8mm studs, ensuring they bottom out.
Remove the appropriate bolt from the central position on the crankcase, and test fit the manifold block clamp. Some careful bending may be required (use a vice) to ensure the top lugs present correctly to the manifold block locating bracket. Check also that the top bolt can slide up the manifold bracket slot - some filing of the casting may be required.
When satisfied, the bracket should be bolted loosely in position, with the top bolt and self-locking nut in place, but loose.
Ensure that the two manifold gaskets are positioned correctly on the heads. Do not use sealant.
Fit one induction manifold without tightening using washers and self-locking brass nuts or, if you must, the plated steel nuts supplied with the kit.
Position the correct size pipe clips and flexible couplings, then fit the manifold block (with the vacuum pipe forwards towards the gearbox), pushing it on to the pipes as far as it will go.
Fit the remaining induction manifold (don't forget the pipe clips and flexi seals), then position the manifold block centrally between the assembly.
The manifold support bracket should now be located.
Tighten down the manifolds after ensuring the best all-round fit, pulling down uniformly up to 14 lbs/ft.
Tighten the manifold block clamp. You may find that the clamp only just nips up to the manifold!
Pull the flexi sleeves over the manifold block, and secure.
Finally, position the carb and gasket on the manifold block. Do not fit nuts at this stage. The throttle linkage should be on the left.

Modifications
There are two considerations:
1/. How to best connect the vacuum pipe.
2/. How to connect the throttle cable.

Vacuum pipe
My solution was to turn up a bulkhead fitting out of hard nylon (Delrin), so sized that it located through the exisiting hole in the bulkhead. The fitting was pushed in from the engine side to leave a spiggot 30mm long on the engine side, followed by a flange, then a 1cm. shoulder to locate through the bulkhead, and finally another 30mm long spiggot, which exactly matched the position of the existing flexible pipe, attached to the non-return air valve.
The flange was located to the bulkhead using three bolts.
Push home the short vacuum hose under the van, and lock with a hose clip.
A suitable length of re-enforced flexible thick-walled pipe was obtained to connect between the fitting on the bulkhead and the manifold block. Some heating of the pipe ends was needed to ease the pipe onto the fittings.
Make sure that the flexible pipe is strong enough not to completely kink where it comes off the manifold block against the bulkhead.
For good measure, secure all joins with pipe clips.
THROTTLE CABLE.
Sighting a line directly from the carb throttle plate to the bulkhead, it will be obvious that the existing throttle cable is out of position by about 100mm. On pre 1971 vans it would be possible (I understand) to drill a hole through the bulkhead and re-position the throttle cable, using of course a turned up nylon retainer for the throttle cable outer sleeve.
The 2 Litre. Bay however, has a bell housing support bracket blocking access, allowing at best only about 24mm available for re-positioning.
My work-around was to utilise the hardened steel "U" bracket supplied in the kit, (which would normally be used for twin carb. fitting), to extend the length of the throttle shaft. The original cable entry from the bulkhead is retained.
An aluminium plate was made up, slightly larger than the supplied throttle plate. A second identical plate was shaped with a slot to locate the end of the "U" bracket.
A 6mm bolt was passed through the centre of the:
• ‘U’ Bracket (open slot)
• Keyplate
• Backplate
• An 8mm Steel Washer
• Throttle Plate
Using two unused holes in the throttle plate, the throttle plate was bolted to the two aluminium plates, thus locking the throttle plate and "U" bracket together. 8mm nuts were uses as spacers between the throttle plate outer edge and the aluminium back plate.
It is essential, if this extension is made up, to ensure that the throttle plate is rotated to exactly match the actuator arm extension on the "U" bracket, before the periferal locating holes are drilled.
The throttle cable clamp was replaced by a suitable brass bolt.
In my case, the protruding brass bolt head was filed flat down to the threads on one side, allowing the throttle cable the be secured with a minature "U" clamp once the correct cable adjustment was made. This avoids cutting the throttle cable to length, which is not a good idea given that the cable strands, if cut, would certainly spring out like a gin wisk.
The ball fitting is located on the outside of the throttle plate, on the last hole (nearest the back of the car) on the quadrant.Do be certain that the made up aluminium plates do not foul the top of the flexible manifold coupling. - There is very little space and careful profiling was required in my case.

Final Assembly
After securing the new throttle plate extension assembly onto the throttle spindle (don’t forget the tab washer) remove the four long studs from the top of the carb.
Fit the crankcase breather nylon fitting to the air filter, and the filter to the carb. using the 6mm. bolts supplied. No washers were supplied in my kit, so do use some. Do this work off the van to avoid dropping bits into the engine.
Fit the supplied gasket (dry) and the carb.
Before tightning down, you will need to extend the length of the new throttle spring retaining bracket, to allow a direct pull of the spring to the re-positioned throttle plate. I used part of the 90-deg. bracket otherwise redundant, and simply rivetted it onto the original plate. I used a bolt to anchor the spring to this extension, and drilled a small hole in the edge of the throttle plate close to the ball fitting, to locate the other spring end.
In my case, the notch on the original plate needed filing out to fit properly.
There is a new length of fuel hose supplied, which ideally should be used. I have used the existing twin fuel feed, with one leg blanked off.
Similarly, I have used the original power cable to the auto throttle, having taped up all the unused plugs. This is because I don't have a dual plug for the coil fitting at this time.

Completion
Check that all work has been completed, that there are no "loose ends" and that the throttle cable is available through the original hole in the bulkhead.
Fit the vacuum advance retard tube between the distributor and carb.
Fit the power cable from coil to auto choke.
Fit the crank case breather pipe.
Check underside, and then place the van back on all four road-wheels.
Place a brick or suitable weight onto the throttle pedal, and then pull on the throttle cable to ensure tension, while clamping up the end of the cable to the fully open throttle linkage.
Back off the ball joint locating stub by one turn and replace on the ball.
Check that with full accelerator pedal travel the carb throttles are fully open, but with just a smidgin of extra movement to avoid damage to the throttles.
In my case, the slack in the cable when the throttle pedal is released is just right, needing no further adjustment.
There remains only the petrol tank breather pipe to attach. At the time of writing I have not done this, but plan to drill a small hole in the air filter lid, and simply hold the pipe in position using two electrical cable rubber sleeves.

Startup
Turn the throttle adjust screw one half turn clockwise.
Check that the fuel pipes are secure.
Check that there is no binding, fouling of the cable, over-centre locking or sticking throttle. Any of these sysmtoms can prove extremely dangerous under driving conditions.
Reconnect the battery.
Start the engine and allow to warm up. (Blip the throttle to make sure that the mechanical choke moves off its cam).
Set the idle speed to approx. 900 r.p.m.
Turn the air bleed screw (front of carb above vacuum pipe) in until the engine speed starts to drop, then out one-quarter turn.
Reset the idle to normal idle revs. Job Done!

Conclusion
In my view, this conversion is not better than having a pair of original carbs in good condition and correctly set up. However, it is 100 % better than struggling with old worn leaky originals with additional air leaks through cracked balance pipe rubbers etc.
My engine is now very tractable and as smooth as new. The new carb does struggle for breath a little, but performance generally is very acceptable, given that my engine is fitted with low-compression pistons.
Provided the new induction manifolds fit correctly and you are prepared to make up the odd fitting, I recommend the excersise.
Note: The suppliers suggest that larger jets may need to be fitted if prolonged operation is intended above 3000 ft ASL.

© Peter J. Aburrow