22r exhaust manifold glows red

Black Bear

Black Bear

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Raleigh, NC
this is an 81 motor on propane. New timing chain but this motor has never run on propane. The mixer has been rebuilt and tuned by gotpropane. If i go for a quick run, say 4 miles the manifold is glowing red. I did have a manifold leak, but it has been repaired. From what i have read a lean condition can cause the excessive heat at the manifold, what about timing? Im set to 8 or 9 deg with the vaccum advance blocked. Is there something I am overlooking?
 
Sounds like timing is off, Mine did the same. Throw the timing to it. IIRC mine was at 22* with a efi dizy.
 
do you have to block the advance? I have heard that you do, and that you do not have to block it off.
 
I added more timing. I maxed out the adjuster still runs great, doesn't knock, but it still gets red after about a mile of driving in the neighborhood.

I spoke with carey at gotpropane. His suggestion was to add more timing and make sure the vacuum advance was working properly. Im going to try to find a wide band 02 so i can see if its a lean or overly rich condition.
 
Not completely sure on a 22r but most propane systems still use the vacum advance, Youre condition sounds like lean to me, youre idle may be set correctly but youre main misture sounds lean.
When you stomp on the throttle does it hesitate or take a second to spool up? If it does you are probably lean.
 
No hestitation revving up. I verified cam/crank timing, it's correct. Did a compression check and it's low 90 is the lowest 120 the highest. Not good but I knew this motor was wore out.

The mixture screw is only for the idle circuit. Not sure how to richen the high idle mixture.
 
Black Bear said:
No hestitation revving up. I verified cam/crank timing, it's correct. Did a compression check and it's low 90 is the lowest 120 the highest. Not good but I knew this motor was wore out.

The mixture screw is only for the idle circuit. Not sure how to richen the high idle mixture.
Click to expand...

Did you get the regulator and lock off from gotpropane? If you didnt and you are using used parts a rebuild kit might help. The insides of those things were caked with white corrosion on mine. probably wouldnt flow half what it was supposed to. Rebuild kits on www.helmarparts.com arent pricey at all. As far as I know there isnt a way to adjust high idle mixture on the mixer you just have to be supplying the right amount of gas to the mixer.
 
maybe a vaccum leak, clogged exaust, bad 02 sensor?
maybe not, the only time i've seen that on my motors was right before one of them locked up and when i was running the other one way to hard.
 
thats a good question.. the mixer has no markings on it what so ever.

I have a wide band o2 coming, so we'll see if its a lean condition or other.
 
ok, i could be waaaay off, but it is just a thought so dont hate! you realy need at least 100psi for proper ignition, that being said could the cylinder that has 90psi be partialy igniting your fuel and the rest burning in the manifold? thuse causing the cherry red hot?
 
is there still a catalytic converter in the exhaust stream ? if so and it is partially plugged ( melted ) it's now an exhaust restriction.

may be why your manifold gaskets have been blowing out as well.

RAW fuel ( gasoline or LP )in a converter will cause a converter to melt down.
 
closer to the first link but not the same. the top is different, and it has 5 bolts for the cover not 4.

Idling will not maintain the glow. So if i drive it around the block and let it idle, the manifold will cool down and not glow.
 
No, and I really have no idea what you mean by colder. less gap, different plug?


i do have a pic of one of the plugs when i did a compression check.
 
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