Edgar Westbury Wallaby ignition

In summary, the issue was the ignition timing which was set bang on TDC strange how it didnt even try at that setting but advancing simply by eye approx 10-15deg got her running. The carb isnt the best marriage for this engine so if anyone has any ideas on a better alternative that would be great. I now need to change the cooling to add in a water pump to move water around the engine instead of just relying on the heat syphon method i will still use the old water tank with sprey bar (or maybe get a radiator). Thanks everyone for your help on this.

Carburettors for small four strokes are a problem. Most commercial ones are designed for high revving two stoke engines. I built a small constant depression (SU type) carb for my twin which worked well. It is now running with mechanical fuel injection.

Computer CPU cooling radiators are cheap and work well along with their electric fans. In this case there is a gear type water pump for circulation.

Where did you get the water pump from ? i can find one with ideal inlet/outlet sizes to avoid pipe size increase i.e. pipe in pipe but it is 12V and 5ltr a min, even say at 6V that pump might be a bit aggressive. do you have a water header tank or is a reserve built into the cooling radiator ?

I made the water pump for this engine, it is built into the distributor drive. I have used a pump like this with a 5V supply as a fuel feed for another of my engines. At 12V it should supply more than enough.

bedienungsanleitung-207894-modelcraft-modelcraft-kraftstoff-getriebepumpe-benzinfest-foerdermenge-06-lmin.pdf (conrad.com)

I fixed a small filler/breather to the top of the radiator but otherwise I just use the reserve that is there.

In addition is the radiator/fan unit from china ? the only integrated units i can find are from china.

Thanks i found that pump, the water tank i have is quite large holds about 1ltr and has a sprey bar at the top water input from the engine. So for now the pump circulating coolant around that tank might be ok.

I think that the radiator, fan and finger guard were bought separately. The fan and guard probably came from Conrad and the radiator from Amazon Germany (I live in Switzerland). This allowed me to choose the size and voltage. I am using an 80mm radiator which is borderline. You should probably think about a 120mm one.

Heater matrix from a scrap car?

The radiator from a car would be an overkill, since it is designed to deal with the heat rejected from 50 or more bhp.

This engine is small and of low power, so the matrix from a car heater, or an old under seat box heater from a bus should provide more than enough cooling.

I would not bother with a spray bar, to minimise restriction to coolant flow.

I am not even sure that a circulating pump is necessary.

The old Fords and Austins used thermo syphon to cool their engines which produced no more than about 40 bhp.

So their cooling systems only needed to dissipate the same amount of heat (If you do a heat balance, the heat to coolant , and heat to exhaust, each roughly match the power at the flywheel ).

The Ford export coolant pump was only used by the special builders, and 750 Club racers where the engine had been tuned to deliver more power. And being a side valve, an 1172 cc engine is unlikely to be capable of delivering much more than 50 bhp per litre.

So an engine of 29 cc is unlikely to be rejecting more than 2 bhp to coolant. Calculating the B Th U or Calorie equivalent of 2 bhp should give a good idea of how much cooling is required.

Howard

Edited By Howard Lewis on 08/10/2022 12:30:54