BN4 Gas Heater alternative fuel source

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Bjorn79type2
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Joined: Mon Aug 15, 2005 6:56 pm

BN4 Gas Heater alternative fuel source

Postby Bjorn79type2 » Tue Dec 13, 2005 11:38 pm

Hi everyone!

Was just wondering if anyone out there might know how to convert an installed and working BN4 heater over to LP fuel? Would it be as simple as I think it is by just disconnecting the fuel lines and buying a conversion kit and switching it to a propane tank?
I just don't like the emissions that this heater pumps out! It's horrible...
Propane in theory should make it burn cleaner with little or no smoking.
Any info or ideas would be great!!

Thanks,
Bjorn
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raygreenwood
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Postby raygreenwood » Wed Dec 14, 2005 7:13 am

I think there may have been some at one time that ran on propane. I would bet it is not simple. Calibrating the flow and temperature cycle with the existing high limit switch and thermo probe switch will be tricky. Metering the flow with the existing contact points will be a challange. It will require a different burner mantle assembly and possibly different blower settings.
There should be no noxious emmissions. If you are smelling heavy exhaust, then chances are, either your initial combustion/ignition is incomplete and/or yoour fuel flow rate is too high...which is easily adjustable. The actual usage of fuel is very low. You lose perhaps 2 miles per gallon at worst with highway use. Maybe 3 in the city. If your fuel is properly adjusted...then you should smell next to nothing from teh tailpipe.
Ray
Bjorn79type2
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Joined: Mon Aug 15, 2005 6:56 pm

Postby Bjorn79type2 » Wed Dec 14, 2005 1:46 pm

Thanks for the info.

I do smell exhaust but I would not call it "heavy" and there is a little bit of black smoke that is emitting from the tailpipe of the heater. How would you go about adjusting the fuel flow if this is what's causing the smoking or smell? The heater has been serviced but it has always smoked a little and smelled to some degree. It will smoke worse when the car is at idle and not moving. I also live at 6250 ft. above sea level. Could the altitude be a factor? Should I have it serviced again and if so, then what would YOU ask them to do specifically?

Thanks Ray,
Bjorn
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raygreenwood
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Postby raygreenwood » Wed Dec 14, 2005 3:25 pm

Yes, The altitude is a big factor. If there is less oxygen...the ratio will run toward more fuel. How to calculate this? Not sure. If you can get an idea from someone, as to what percentage less of oxygen there is at your altitude as compared to say....1000 feet above sea level, then you can scale back teh fuel delivery by about that percentage.

If you look underneath the drivers side of the car...just forward of the rear fender well, you will see the fuel pump. There is a lock not on the delivery end. It allows you to turn teh nozzle that connects to the fuel pipe...with a wrench. I cannot remember which way is which...but one direction is less...the other is more. This is in the Clymer brand manual. You need to disconnect the sparg plug for this. You will run the heater with teh fuel line disconnected and running into an accurate measuring vial. There is a specific number of cc's per minute the fuel pump must run. I will look in the books tonight. From this factory rating of cc's per minute, I would subtract the amount of oxygen you are deficient at your altitude. For ewxample, if you have 25% less oxygen at your level...use 25% less fuel.

Also, be sure the battery is charged and all of teh connections are clean. Set the fuel delivery with teh headlights on...especially if you are more prone to driving with the lights on when the heater will be on. this is because....there is no rectifier for the power link to the heater unit. It has a tendency when the alternator is kicking in and out during charging while running...to accelerate its speed slightly (the fuel pump clicking speed)...when the alternator kicks in. It is best to have someone revving the engine just slightly over 1500 while doing this adjustment so teh voltage is stable. Its actually a very simple adjustment. Ray
Bjorn79type2
Posts: 18
Joined: Mon Aug 15, 2005 6:56 pm

Postby Bjorn79type2 » Wed Dec 14, 2005 7:46 pm

Thanks Ray!

I will do some of my own research into the specifics of this particular heater and all of its mechanisms before I jump off the bridge (that, and it's 20 degrees outside right now. No garage). Your info is really great. Please let me know if you come up with anything else.

Bjorn
metropoj
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Joined: Thu Sep 05, 2002 2:01 am

Postby metropoj » Thu Dec 15, 2005 9:08 am

BN4 is the 'torpedo' style heater. The fuel pump should be mounted directly under the heater itself on the mounting bracket, in the engine compartment .... no ?

My BA6 fuel pump is in the area Ray talked about.... either case what Ray describes for adjusting the pump is true ....
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raygreenwood
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Joined: Wed Jan 22, 2003 3:01 am

Postby raygreenwood » Thu Dec 15, 2005 10:34 am

Thanks for the clarification. I could not remember the number differences. The one I have is on my 412. I believe it is BN-6?
Either way...you can simply adjust a bit at a time at high altitude..so it does not smoke. At that point...you will want to examine if your standard dial settings give you too little or too much heat. It is a good idea to mark where you changed the factory adjustment from so a quick twist at normal altitudes can put you back to normal fuel mixtures. If you run it too lean...it overheats. Thats not a real worry because all that will happen is that the overheat switch in the top will shut it down. Ray
Bjorn79type2
Posts: 18
Joined: Mon Aug 15, 2005 6:56 pm

Postby Bjorn79type2 » Thu Dec 15, 2005 3:48 pm

Thanks guys!

As soon as I get a chance I will readjust the the fuel pump and let you know how it went.

Sincerely,
Bjorn
abutler
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Joined: Mon May 10, 2004 1:46 am

BN4 smoke

Postby abutler » Mon Jan 09, 2006 3:55 pm

Hi, I've found that I have to remove the glow plug and clean it with a propane torch quite frequently. When it smokes it lets me know its time to clean again. I have collected about 4 plugs so I have a continuous supply before recleaning.
metropoj
Posts: 997
Joined: Thu Sep 05, 2002 2:01 am

Postby metropoj » Thu Jan 12, 2006 8:43 am

raygreenwood wrote:Thanks for the clarification. I could not remember the number differences. The one I have is on my 412. I believe it is BN-6?
Either way...you can simply adjust a bit at a time at high altitude..so it does not smoke. At that point...you will want to examine if your standard dial settings give you too little or too much heat. It is a good idea to mark where you changed the factory adjustment from so a quick twist at normal altitudes can put you back to normal fuel mixtures. If you run it too lean...it overheats. Thats not a real worry because all that will happen is that the overheat switch in the top will shut it down. Ray


Heh, the 411/412 double wishbone always gets me for number clarification too :) i think it's a BA4 ....... ?? Damn, now I cant remember .... :) ..... I always thought the dash timer for the heater / clock was the coolest thing I'd ever seen in a car ......

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