DES 8/1 Propane Conversion project

[BruceM]

Good thoughts, guys.  The engine is not pulling a load, yet, so fuel demand should be minimal, but I'll check the tank temp today.

[BruceM]

Tank and hose aren't getting cold, today the missing starts almost immediately.  I'll see if it goes away with the spark system.

[George A]

Just another thought Bruce..........have you disconnected the propane line then turned on the tank valve and just let the gas come out? It could be that the regulator is goofed up inside and only works intermittently.

[carlb23]

You would think that a regular barbeque tank should easily provide enough flow to run the 6/1 especially unloaded.  Most 4 burner gas grills are 48,000 Btu's and the tank doesn't normally freeze. If diesel is aprox 130,000 BTU's per gallon and a loaded 6/1 uses aprox 1/3 gallon per hour then even loaded it should only be needing aprox 43,000 BTU's.   That being said as mentioned above you may have a bad regulator.

Just my 2 cents

Carl

[broncodriver99]

Newer propane tanks have flow limiting devices built in. I have had a couple that were especially finicky that I had to slowly open the valve on or they would trip and shut off. It may have something to do with it. Another avenue to venture down anyway. Do you have an older or different tank you can try?

[buickanddeere]

After readinthe article. I'm thinking the LP carb/mixer/regulator are too large .

[38ac]

My only experience with propane is with a hit miss engine and hot tube ignition. Mixture is critical with that one and the only way the tank with shut off valve will work is with a surge tank between the engine and the LP tank, otherwise the call for fuel would cause the shut off to activate . I suggest a gauge in the line as a first step so you know what is going on there.

[32 coupe]

I second the gauge idea.
How do you know what it's doing without one ?
I'm just say'n. ..


Gary

[Tom]

Just ran into this at the fire department. We made an LP burner in the bottom portion of a 55 gal barrel filled with water. It's used for fire extinguisher training and they could not get enough flame. I found that the bottle adapter used had a restriction in it. After drilling it out we had flames 8' high. 

[BruceM]

Thanks for the good ideas, guys.  The CA55 carb is rated for a big range of engines  but a Listeroid is in the range.  What bothers me most is that the idle and rich/lean main adjustments don't seem to make any difference in running at all. A gas line pressure gauge is needed to see what's going on and I'll get one ordered tonight.

I got the hall effect/spark circuit bread-boarded and tested this AM, hopefully will get it on the engine over the next few days.  I'm going to try fixed timing off of the former injection pump cam-bolt with a magnet on top, hall effect switch epoxied to an aluminum plate where the injector isn't.  Injector cam-bolt can then be adjusted to dial in spark timing. A 555 IC provides a 4ms pulse to a Mosfet to charge the coil and discharge it.  I may have to add some circuitry to retard timing for starting if that proves a problem.

Big rush on getting a roof over my new neighbor's head as he's got to be camping here on the first of April.

[BruceM]

Impco is pretty lousy on documentation, but I did find that some of their carbs are designed for 5" of WC regulators. I'm thinking perhaps the BBQ pressure regulator is a bit too high for it.  Another document mentioned that the fuel rich/lean has little effect at idle/light loads.  No luck in finding an adjustable pressure BBQ regulator so far, but perhaps I can find a high (10-20 psi) then adjustable  low (5-11 inches WC) regulator.

[carlb23]

something like this?

http://www.ebay.com/itm/Adjustable-Propane-Gas-Regulator-BBQ-Grill-Burner-Wok-Fryer-with-4ft-Hose-20PSI-/161439781888?pt=LH_DefaultDomain_0&hash=item25968f9400

[Thob]

Here's one that's adjustable.  It doesn't say it is, but you unscrew the blue plug and there's an adjustment screw underneath.

http://www.amazon.com/Camco-59333-Horizontal-Propane-Regulator/dp/B0024E6TX2/ref=sr_1_1?ie=UTF8&qid=1426798850&sr=8-1&keywords=camco+horizontal+two+stage+propane+regulator

The easy way to measure pressure on one of these is to put the outlet hose in a bucket of water.  Whatever depth it takes to just flow propane can be measured as the setting in inches WC.  Typically the Impco carbs are going to expect 11 inches WC, which is what the regulators are normally set for.

[32 coupe]

Bruce,
After spending some time thinking about this, I think the spark plug
and your homebrew ignition system will cure your woes.
I would not worry about any advance/retard system. I just
don't think it will be necessary.

You do.know.the RC plugs com in different heat ranges ? I played
with rc planes for years and learned this early on after a few
tuning problems.

I'll amble off now,
Gary

[BruceM]

Raining now but I was able to open up the BBQ LP regulator and can now adjust it.  Thob's simple water bucket calibration method I can do while waiting for the pressure gauge to come on Monday. (Thanks, Thob.) I will place the pressure gauge right at the carburetor so there will no more mystery on that issue.

I am suspicious of my homebrew smartplug, and will report back on how the spark via coil and injection pump cam/bolt sensor works out.  I have both installed, so can easily run and switch back and forth.  I've got to solder up and heatsink the mosfet which switches the coil current since the coil draws up to 6.5 amps for the 4 milliseconds just before the spark.

I wanted to publicly thank 32 coupe for the very nice offset idler bolt he contributed for this project.  She's in good running shape re: gear lash now, from 0.013 to about 0.004" as measured with the music wire on idler tooth to dial gauge method.  I think his offset sleeve on turned down bolt method is great for moderate offsets since you could try several offsets to get it just right.  I'm not sure what the practical  limit might be, perhaps 0.030?

I'm very grateful for the helpful and encouraging project support I've received here!

Bruce