The MGA With An Attitude
BILGE BLOWER To Cool Carburetors, 3-inch #4 -- CB-208D

3-inch bilge blower On 03 August 2012, Steve Gyles in Church Crookham, Hants, England wrote:
"Got my blower. I found that windscreen channel piping makes an excellent seal, perfect width for the channels in the Atwood blower and makes an excellent fit into the duct. I held the rubber extrusion in place with wire, making the seal sit extremely well in place. That pump certainly shifts some air"!

On 04 August 2012, Steve Gyles wrote:
"I did a heap of tests this afternoon doing a dozen runs or so with the blower in two positions. Interesting results. Not a hot day, ambient temperature 70F. Without removing the filters I could not get the blower in the left MGA vent so I put it in the right hand vent with it exhausting outwards. I had the temperature probe positioned in free air just in front of the heater box and in a second test I positioned the probe between the 2 carbs in free air. The engine temp was 175F when running at 40mph and 185F when stabilized at idle. Throughout the tests I was unable to detect any difference in temperature with the blower switched on or off. I was a bit disappointed. I then repeated the tests with the blower in the front vent. Somewhat surprisingly I got exactly the same results. I then taped the probe to the rear of the front fuel bowl. Again, I got no change in temperature both at 40mph, nor at idle with or without the blower.
"I then put a deflector plate on the blower to direct the air at the front fuel bowl. At 40mph the front bowl measured 112F with the blower off and 98F with the blower on. At idle the bowl measured 132F blower off and 102F blower on. I then repeated the tests with the probe at the back of the rear carb. At 40mph it was 112F blower off and 106F blower on. 3-inch bilge blower with air deflector At idle it was 122F and 106F respectively. Conclusion: For this modification to work to any significant benefit it requires a deflector plate".

On 06 August 2012, Steve Gyles wrote:
"I am in the process of fitting a deflector plate. The reason for only deflecting half the airflow slightly is to retain the rest of the cold airflow for the filter boxes. I plan to make the deflector moveable so that when the fan is not in use the deflector is neutral. I am thinking of using a linear solenoid linked to the 'rudder' bar".

I'm guessing this is overkill, or a solution looking for a problem, but Steve seems to think it may hold some benefit. Stay tuned. -- Barney

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