fbekholden.com

Sonic injection are doing a run of Su manifolds to suit the 12 port head. No one else has ever made them. Keep your carb size to a minimum. If they are too large your mixture spread will be uncontrollable.

Yes, that is the source I was referring to. 1 3/4” it is and thanks for the advice.


FB ute fixer upper, EK van on rotisserie

Started finishing off the set up work for the dyno. Getting close to annoying the neighbors.

I hope you are going to video it for our listening pleasure .......

This dyno unit has been a drama. It's had to be drained and pulled out for repairs to leaking fittings that are welded in. Contending with 500 litres of oil is a pain, especially hand pumping.
All welds were ground back, cleaned, pressure tested, re welded, pressure tested again, and final sealed with loctite Wick In. The leaks were mostly due to porosity in the welds.
After reassembling the unit and refitting the engine, tuning runs started in ernest. Light load ignition mapping was done. After getting stuck into full load testing the dyno let go. I saw around 2500psi at around 2000 to 2500 rpm. The split flange fitting on the pump outlet failed. The oring flange was brazed to the pump outlet pipe. This pipe sees full pressure between the pump and relief valve. Luckily it's inside the dyno reservoir. Pressure readings so far indicate good HP for around 1/2 throttle. They equate to about 109 hp at 4200 rpm so far. I'm not expecting anything over 120 hp realistically.

Well the dyno is repaired and running now. Back to more tuning. Ignition curve is done, but I need to re-phase the distributor slightly. A start has been made on the needle profiles vs O2 readings at specific load/rpm/piston heights. The PCV system has been tested and is working well. There is no need for a PCV valve as the HIF SU carb regulates airflow across the PCV port automatically.
It's a juggle on the dyno without any electronic load or rpm control, but better than seat of the pants tuning.

Todays job was knocking up an adjustable breaker plate set up so I can adjust the distributor phasing on the fly.

Very clever

This made me think of your build Craig:



Mallory twin point with adjustable breaker plate for grey motor.
Just came up on old Holden cars and parts sell swap.

I'd love to see the insides of that one. I'm not sure of the reasoning behind it though, considering the mechanical advance would move the cam and rotor button so phasing would be affected. I'm assuming it's a timing adjustment or maybe advance rate adjustment considering the adjuster is so low in the body. Certainly a rare peice.

Ask snd ye shall receive…..


@ $500 it’s still there


FB ute fixer upper, EK van on rotisserie

More info on the Mallory Double-Trouble Lightning Whirler:
Cheers,
Harv

Could that thing sticking out the side be tacho drive?


FB ute fixer upper, EK van on rotisserie

Errol62 wrote: Mon Jan 26, 2026 9:01 am Could that thing sticking out the side be tacho drive?


FB ute fixer upper, EK van on rotisserie

The documents in the Pdf's suggest tacho drive, but I cant see how it would work being that a worm drive would have to be in the opposite configuration or it has a complex drive system within.

I've been dealing with an off idle rich condition with these SU's. Slight part throttle see's the mixture swing from 12.5:1 to 10.8:1. Further throttle after this see's it lean out back to normal conditions. This has been a known issue in the past with this set up.
From what I can work out is that with the idle mixture (jet height) set at idle, pistons just off their stop, everything is ok.
Further throttle see's added depression at the jet/s without much more lift of the piston/s. With fuel being heavier than air, more fuel is drawn thus the richer mixture. Once the pistons start to rise at an increased rate with further throttle opening, mixtures start to lean out.
I have tried numerous spring weights but this changes the mixtures throughout the whole range. Needle profiling is next to impossible for this problem due to the small position that needs to be altered. I am working now with trying to bleed some ported vacuum to the float bowl vent as this will lower the fuel level in the jet and lean out the fuel ratio. Being ported vacuum it will only happen at the part throttle condition.
Anyway today I fitted manometer type tubes to the float bowls so I can see the actual levels and what the will be doing with a small amount of vacuum added to the vent tube.