Overheating due to balance pipe

[RonShurley]

I have almost completed a long abandoned, unfinished Lomax 224 with an M28/1 engine.
All the original ducting & fan were gone. It has a standard 2CV exhaust system, complete with balance pipe via the carb manifold.
It runs well for the 1st mile, then easily stalls, may backfire, become hard to start etc. I assume due to carb overheating, fuel vaporisation etc.
With an infrared temperature gun, I can see the exhaust headers are about 250C, the barrels about 150C and the carb about 40-50C.
I've cut a hole in the middle of the bonnet, allowing the air-filter to project and the rising heat to escape. I’ve lagged the exhaust mid-sections with fibre-glass wrap.
I've added an 8" PC fan to the grill, that's woefully inadequate. I've ordered a car-radiator 9" 80w electric fan.
I've re-jeted the 18/26 carb with 112/95 main jets. I don't think it's running weak anymore.
I fitted contact-breaker assisted electronic ignition that is timed as accurately as I could (the flywheel hole had been skimmed off).
Have all other Lomax owners fitted non-standard exhaust systems without the balance pipe? Thereby avoiding this carb overheating?
Should I cut the balance pipes out?
I can’t weld but I know welding cast-iron can be lead to cracking, so it might not be easy to weld the exhaust headers.
The balance pipe is 1” OD so I might be able to cut a 1” BSP thread on the stubs and find a cast iron 1” ID end-cap to fit.
Am I on the right track? Or have I overlooked something?
All contributions gratefully received!

[notsmartcar]

Guessing the timing is probably not a good idea but in your case check that the voltage at the battery is not above 14.4 when reving and the minute it starts to misbehave try another coil

[Davidm]

My Pembleton has the 2cv carb. on standard 2cv manifold with balance pipe and i have had no fuel evaporation problems. I have no fan cooling and if anything the sump oil temperature tends to be lower than i want so in cold weather i partly blank off the oil cooler. Only in hot weather has the oil temperature occassionally exceeded 90C.
Are you confident the fuel pump is keeping the carb supplied ?
Davidm

[RonShurley]

Thank you DavidM, If your Pembleton is Ok with a balance pipe, my Lomax should be Ok.
I fitted a W209 temperature control set to 100C with a probe on the Oil cooler pipe and it clcked the fan on. So I know my oil exceeds 100C.
Thanks again, Ron.

[RonShurley]

Thank you NotSmartCar,
I fitted an Ammeter showing it was charging so had never checked the Voltage when running.
I've just checked it and was astonished to see 18.8v, I checked it with a 2nd meter, exactly the same.
I don’t think it was charging with the original Ducellier regulator, so I had fitted a Hella solid-state regulator.
I assume that the excessive voltage causes intermittent failure in the ignition coil?
This is probably why the 1st electronic ignition I fitted (Sparkrite SX4000) failed after very little use.
The 2nd (Gammatronic PowerDriver) survives the excessive voltage.
Thank you very much NotSmartCar, I will replace the Hella regulator and make sure it stays under 14.4v.
Ron.
PS. I had tried a Facit electric fuel pump and then a new mechanical fuel pump.

[notsmartcar]

Don’t change the regulator yet The regulator has 3 wires one from the ignition switch .one goes to earth and one to the alternator ..connect the earth on the regulator directly to the battery negative and the one from the ignition switch + live directly to the battery positive. think then you will see which of your wiring is faulty. Ps unfortunately long term your coil is now toast. The exhaust manifold is weldable you will be pleased to know (I use my mig) .. the carb will not over heat while driving but I’ve had a carb freeze and stop the engine at 16C. though

[RonShurley]

I connected the regulator directly to the battery & Alternator field. Still 18.8v.
I've ordered another Hella regulator.
ECAS ignition coil is £49, I assume a 12v M.Bike twin lead coil would work aswell? (as I fitted on my Honda CB160).
Any recomendations?
Thanks again NotSmartCar. Ron.

[notsmartcar]

The wire from the regulator to alternator stays in place it’s only earth and live wire on regulator you connect to battery (you are basically checking for voltage drop in the feed to the regulator. ..I presume it’s a 2cv alternator and not a visa one …( a 2cv one has the small wire going to the brush pack while on a visa one the regulator is built in to the back). ohms are important on coil so in your case I would get a new one from Ecas.

[RonShurley]

I assume it's a 2CV alternator, it's an ISKRA with a large connector for output and a smaller spade connector for the field coil.
With the ignition off or with the engine running I get 0.2v drop between the battery +ve and the regulator +ve
and 0.01v drop between the battery -ve and the regulator -ve.
My Ignition coil (disconnected) shows 3.5 Ohms on the the 200 Ohm range (Cheap digital meter).
Thanks again NotSmartCar. Ron.

[RonShurley]

I've removed insulation from the regulators connectors so I could measure insitu.
The battery was now at 12.94v and the regulator had 12.87v, only 0.07v difference (ignition on, ignition coil disconnected).
The battery clamps, leads and earth leads (Gearbox to chassis and steering column hoop) are all new, so I'm surpried it's that much.
Thanks again NotSmartCar, Ron.