Manifold Heater question

[fredrader]

Hi All,It got down in the low 30's the past couple days and when I went to start the deuce I had to crank it longer than usual..I cranked it for about 3-4 seconds and flipped the manifold heater switch and held it to the right for about 3-4 seconds and it fired up..How do I tell if the heater is working or not ??? How do I test it ?? Thanks ...Fred

 

[cranetruck]

The flame heater can be tricky. Wrote about it (MVM issue Oct, 2003) and fabricated a monitoring device as shown below.
I found that the flame is easily snuffed out in the turbo application, where the intake manifold adapter is more narrow than for the N/A engine. The speed of the air flow is higher.
It's obviously not good to squirt raw fuel into the inatke manifold if it doesn't ignite.

 

[fredrader]

Thanks,That looks like a great idea..I don't really know how it works though..Does the heat from the working flame heat the switch and make the light come on or what..

 

[cranetruck]

Fred,
It's an optical sensor. The light on the dash will actually flicker as the flame flickers (=very responsive).
On the work bench it is sensitive enough to detect a lit match several feet away.
Installed, it will not turn on by the spark plug spark, only the flame and the optical sensor is an inch or so away from the flame and is not damaged by it.
You should not use the flame heater at any rpm higher than idle, the increased air flow will definetly extinguish the flame.
If you wonder about the spark plug, it is powered by a vibrator and produces a continous spark for as long as you press the switch.
The spark plug gap should be 0.10 inches.
You can test the nozzle by removing it and temporarily installing it in a clear plastic jug and observe the spray pattern. It should produce a very fine mist in the shape of a cone.
The engine needs to run since the fuel comes from the pump on the fuel injection pump. The fuel is filtered through a filter (replace if need be) by the flame heater pump on top of the engine. The pressure of the fuel going to the flame heater nozzle should be about 90 psi.
With the flame heater switch turned off and the engine running, there should be no fuel leaking through the nozzle.

If there is enough interest in the device I can make up some more. Sold only a handful so far over the years. The cost is $39.00 including shipping within CONUS.
The indicator light is extra.

 

[cranetruck]

If I may continue, the following is from the mil-veh list:

"If you have that Military Vehicles article, it describes things to check for correct operation. Mine wasn't working due to broken insulation in the spark plug AND an intermittent ignitor.

Easiest check is for spark by removing the plug and powering up the ignitor only. If spark is steady then check for fuel spray. You can power up the flame heater's fuel pump (with the in-tank pump on also) and look into the spark plug hole for fuel mist. The better way is to remove the injector and inspect for a good fuel spray pattern/mist.

After getting my flame heater working, I bought Bjorn Bramstedt's flame heater monitor and my results were similar to what he found in his testing described in the MV magazine article; with a turbo motor, the flame is blown out when the engine is running. In other words, you cannot operate the flame heater after idling to expedite heating and get it running smoothly, as they describe in the operator's manual as well as the dash plate. On mine, I also notice that there is a good 1 sec delay between activating the heater while cranking and actually getting a flame. I believe this is due to the time it takes for the flame heater's pump to generate pressure and operate the injector."

It was submitted by David Oheim a couple of years ago.

 

[fredrader]

Man that is pretty slick ..If it ever warms up I will check it and see if it is working..I may want one of your inventions if you start making em..Thanks for the help..Fred