Strugling with an American Carke converted 3930

[HUNTERTOWNSEN]

Hi I could reallly use some advice. I am trying to help out a friend with an 79 american clarke /new holland/ 3930 propane vacuum sweeper. My buddy received this unit in payment for a debt, At one point he saw it run. I am the 3rd person to work on it, it was in pieces when i got there. From what im understanding , the tractor had quit running when he got it. He dropped it off to a mechanic to work on it, the guy, I wont call him a mechanic from this point on, Had replaced the condensor for the propane , there was some sort of problem with the distributor , so he replaced it with a used electronic distributor, after a year , my buddy took his tractor back in non running condition. He was told it had ran, i really doubt it. In the meantime somehow it got water in the engine, Idk how, whether being left out in the rain or cracked block or headgasket, idk. So person #2 worked on it, they pulled it apart and had a valve job done. The head was re-installed and thats as far as he went,now I step in. I put the machine back together, but i cant get it to start. This is a propane tractor, I have tried either , gas , and propane, to prime it. I have brought the piston up to tdc, on the compression stroke, made sure the rotor was pointing directly at #1 , then advanced it slightly, the firing order is correct, at least by the intake manifold, it is 123. I have advanced and retarded the distributor to the point of backfiring both ways. You can hear it speed up , but it wont run. I have done a compression test , its even at 100 psi per cylinder. I have checked spark , i am getting good spark on all cylinders, I checked it visibly and I have hooked the pick up coil from my timing light on each wire to make sure i was getting spark on a load. the plugs are brand new and set at .045. There is a timing mark on the crank pulley, but there is not an indicator on the block. There is a bolt hole for one , but nothing there. Now here what is really throwing me for a loop. I messed with the firing order, just thinking since this is a oddball maybe the intake manifold firing order was incorrect, backfired really bad out the exhaust, so i put it back. Now when i first try to fire, i get a little smoke then nothing , if i let it sit, for a few seconds more smoke then nothing , but here is what is strange to me , its a water cooled intake manifold, and after about 30 seconds of cranking , i can feel it get warm????? I did not set the valves, but they are about at 14 on intake and 17 on exhaust, Is that too tight?? any help or suggestions would be greatly appreciated. I am a v8 and diesel guy, this should not be so difficult. If anything does not make sense to you, please let me know and i will try to clarify, pretty much at a loss right now as to waht could be wrong. By the way It could not have ever run with the new distributor, the power was never hooked up. Also I forgot to mention, with my timing light , while cranking , I was getting random spark, so i replaced the coil with a known good one and that solved the problem.

 

[Gale Hawkins]

You are braver than I am.

 

[HUNTERTOWNSEN]

You are braver than I am.

or dumber lol

 

[banjodunn]

G'day is it running the right coil for the electronic ignition I am guessing it will be a straight 12v coil and there will not be a ballast resistor in the system, have you tried disconnecting the propane system and putting some fuel in a spray bottle and spraying carefully down the inlet manifold/


Jon

 

[HUNTERTOWNSEN]

G'day is it running the right coil for the electronic ignition I am guessing it will be a straight 12v coil and there will not be a ballast resistor in the system, have you tried disconnecting the propane system and putting some fuel in a spray bottle and spraying carefully down the inlet manifold/


Jon

Yes , no ballast required, i have even run a lead from the battery directly, I have also tried using both either and gas on the intake, there seems to be no real effect. really at a loss here, thanks for your suggestions though.

 

[Dave M7040]

Hi I could reallly use some advice. I am trying to help out a friend with an 79 american clarke /new holland/ 3930 propane vacuum sweeper. My buddy received this unit in payment for a debt, At one point he saw it run. I am the 3rd person to work on it, it was in pieces when i got there. From what im understanding , the tractor had quit running when he got it. He dropped it off to a mechanic to work on it, the guy, I wont call him a mechanic from this point on, Had replaced the condensor for the propane , there was some sort of problem with the distributor , so he replaced it with a used electronic distributor, after a year , my buddy took his tractor back in non running condition. He was told it had ran, i really doubt it. In the meantime somehow it got water in the engine, Idk how, whether being left out in the rain or cracked block or headgasket, idk. So person #2 worked on it, they pulled it apart and had a valve job done. The head was re-installed and thats as far as he went,now I step in. I put the machine back together, but i cant get it to start. This is a propane tractor, I have tried either , gas , and propane, to prime it. I have brought the piston up to tdc, on the compression stroke, made sure the rotor was pointing directly at #1 , then advanced it slightly, the firing order is correct, at least by the intake manifold, it is 123. I have advanced and retarded the distributor to the point of backfiring both ways. You can hear it speed up , but it wont run. I have done a compression test , its even at 100 psi per cylinder. I have checked spark , i am getting good spark on all cylinders, I checked it visibly and I have hooked the pick up coil from my timing light on each wire to make sure i was getting spark on a load. the plugs are brand new and set at .045. There is a timing mark on the crank pulley, but there is not an indicator on the block. There is a bolt hole for one , but nothing there. Now here what is really throwing me for a loop. I messed with the firing order, just thinking since this is a oddball maybe the intake manifold firing order was incorrect, backfired really bad out the exhaust, so i put it back. Now when i first try to fire, i get a little smoke then nothing , if i let it sit, for a few seconds more smoke then nothing , but here is what is strange to me , its a water cooled intake manifold, and after about 30 seconds of cranking , i can feel it get warm????? I did not set the valves, but they are about at 14 on intake and 17 on exhaust, Is that too tight?? any help or suggestions would be greatly appreciated. I am a v8 and diesel guy, this should not be so difficult. If anything does not make sense to you, please let me know and i will try to clarify, pretty much at a loss right now as to waht could be wrong. By the way It could not have ever run with the new distributor, the power was never hooked up. Also I forgot to mention, with my timing light , while cranking , I was getting random spark, so i replaced the coil with a known good one and that solved the problem.

I think you have to go back to basics.

With the 100 psi engine compression,something is not correct if a valve job was done.

Compressing air in an engine is not different than an air compressor running. The act of compressing air produces heat

Valve clearance issues would not appear with a cold engine as long as there is some clearance.

I would be wanting to check the timing of the camshaft to the crankshaft. If you don't know what I mean I can explain further. There are marks on gears that have to be aligned on the inside front of the engine

Post some photos so we all have a better image of the machine.

Is the engine a flat head design or overhead valve?

Dave M7040

 

[rScotty]

Why in the world would the intake manifold get warm? That's really weird. I can see why a propane manifold might need to be heated to combat the cooling effect of propane expansion in the manifold at high flows & high loads....but immediately get warm? Could there be a heater in that manifold??

I've only worked on one propane powered engine - an aircooled generator - and it runs fine after I put in an extra on/off valve in the propane feed line. Before I did that, it would seep propane through the carb with the engine off and that drained the propane tank overnight. Hmmm....I wonder if you have an electronic valve that serves the purpose of shutting off the propane feed and maybe that valve is not opening when you turn the ignition on? Or somehow not working right...
Your timing and valve settings seem close enough to me. You obviously understand engines.
rScotty

 

[HUNTERTOWNSEN]

Why in the world would the intake manifold get warm? That's really weird. I can see why a propane manifold might need to be heated to combat the cooling effect of propane expansion in the manifold at high flows & high loads....but immediately get warm? Could there be a heater in that manifold??

I've only worked on one propane powered engine - an aircooled generator - and it runs fine after I put in an extra on/off valve in the propane feed line. Before I did that, it would seep propane through the carb with the engine off and that drained the propane tank overnight. Hmmm....I wonder if you have an electronic valve that serves the purpose of shutting off the propane feed and maybe that valve is not opening when you turn the ignition on? Or somehow not working right...
Your timing and valve settings seem close enough to me. You obviously understand engines.
rScotty

The warm intake has me baffled also, but i could physically feel it with my hands, there isnt any type of heater on the manifold although it is does have water jackets on it, I assumed it was for condensing the propane, but as far as that goes, I have learned that the way the bottle set up is , it should be running liquid propane , not vapors, I have talked to the owner and its the original bottle. I have 0 exp with propane systems, so trying to learn about them. I have tried with both the valve on and off, using starting fluid and gasoline in a spray bottle , no real difference. I am beginning to think its compression and my gauge is off, although its a mac gauge.

 

[HUNTERTOWNSEN]

I think you have to go back to basics.

With the 100 psi engine compression,something is not correct if a valve job was done.

Compressing air in an engine is not different than an air compressor running. The act of compressing air produces heat

Valve clearance issues would not appear with a cold engine as long as there is some clearance.

I would be wanting to check the timing of the camshaft to the crankshaft. If you don't know what I mean I can explain further. There are marks on gears that have to be aligned on the inside front of the engine

Post some photos so we all have a better image of the machine.

Is the engine a flat head design or overhead valve?

Dave M7040

Sorry just saw your post, the engine is overhead valve, but the cam timing was not touched. And my thoughts exactly on the valve clearance, I am trying to give as much info as i can. I will try to get some pics. I understand the act of compressing air creates heat, but it shouldnt warm it to touch with 20 to 30 secs of cranking on a water cooled intake. I was thinking valves are leaking back, but I shouldnt have decent compression. I am beginning to wonder if my compression gauge is off, I havent used it in years, but its a quality mac gauge. I have played with it some more, it tries to start, but just wont go. and thanks for your input

 

[Dave M7040]

Sorry just saw your post, the engine is overhead valve, but the cam timing was not touched. And my thoughts exactly on the valve clearance, I am trying to give as much info as i can. I will try to get some pics. I understand the act of compressing air creates heat, but it shouldnt warm it to touch with 20 to 30 secs of cranking on a water cooled intake. I was thinking valves are leaking back, but I shouldnt have decent compression. I am beginning to wonder if my compression gauge is off, I havent used it in years, but its a quality mac gauge. I have played with it some more, it tries to start, but just wont go. and thanks for your input

If you don't know if you can trust your compression gauge, you need to find a way to check it against another known good pressure gauge.

Some rubber hose, a cheap but new gauge, a Tee and a bicycle pump. Connect the new cheap gauge and the compression gauge to the rubber hoses you have coming off the Tee's two legs.

Connect the bicycle pump to the third leg of the Tee with a Schraeder valve between the bicycle pump and the tee to hold the air in as you pump up the pressure.
You can salvage the Schraeder valve from a tubeless tire valve, a tire tube valve or even a valve for adding air to a well pump tank.

Start pumping. The Mac gauge and the new cheap gauge should matches the pressure from the bicycle pump as the pressure increases.

I don't think you would have a water cooled intake as there is no point in it. It does make sense to have a water cooled exhaust manifold to keep the temperature of the exhaust manifold low as is done on marine engines.

Depending upon your skills, by putting together a cheap version of an expensive cylinder leak down test, you could break off the porcelain on a spark plug, epoxy a Shraeder valve into the broken spark plug and thread into a cylinder.
Rotate the engine until both valves for that cylinder are closed. Remove the oil filler cap. Now add compressed air to the cylinder and see where it is escaping. Out the crankcase filler means leaking rings or a hole in a piston. Leaking out either exhaust or intake manifold shows bad valves. Coming out the rad means head gasket or more serious problems.

The wrong head gasket can cause serious problems by not sealing some passages and opening others.

Dave M7040