AC5050 will only start with ether, please advise- we need this thing to run.

[Jerry/MT]

How many PSI should each cylinder average? We got about 250psi per. Compression is 17.1:1 , atmospheric pressure around 14.7 .. would be around 251psi.. right?

Compression ratio is a volume ratio NOT a pressure ratio!

The equation I use to calculate the compression pressure is based on the isentropic equation pV^gamma=Constant (eqn 1) where p is the pressure, V is the volume and gamma is the ratio of specific heats of air.

Sparing you all the gory details, the equation for what you see on a compression gauge;

delta p = p1 x [((compression ratio)^gamma) -1], (eqn 2)

where p1 is atmospheric pressure, gamma is 1.4 and delta p is the compression gauge pressure

Now the isentropic equation assumes constant mass in the cylinder but because of valve timing the mass in the real engine is not constant, and gamma is not 1.4. So K is a constant that adjusts the theoretical value of compression gauge pressure to account for this.

Eqn 2 then becomes delta p = K x p1 x [(compression ratio)^gamma -1] (eqn 3)

Gamma =1.4. From experience K is between 0.70 and 0.75.
So a compression ratio 6.0 engine would have compression gauge pressure at an atmospheric pressure of 14.7 psia would be 124.6 psig (K=0.75). This is what you could expect as a maximum for a engine in good mechanical condition.

I hope this helps you. As a general rule, minimum diesel compressionr pressure is ~ 325-375 psig for a 17: 1 compression ratio engine.


I ain't old, I just been used rough.

 

[UrbannGuerilla]

I hope the OP didn't get bad advice from someone about ether use.

I used the phrase "we" in my OP. It was actually my father that sprayed all the ether. (Not laying blame, but that's the truth) I have never used ether on an engine myself. When I originally saw him doing it I said "You shouldn't use that" (because I drive a diesel pickup, I at least know its a big no-no for engines w/ glow plugs- but the tractor doesn't have glow plugs, so I didn't know enough to press the issue.) His reply was something like "when i was young my brother worked on diesels and he used ether, and it was fine". (Which was probably accurate, 40 yrs ago) I looked up ether use on diesels (after the fact) and found out that method was eliminated from standard practice like 30 or 40 yrs ago. He's 70.

I think the OP is desperate and I wish I could help.

I am desperate. I have sprayed everything w/ a 4 gal backpack sprayer twice now (its prime bug season, and w/o spraying its all a loss) and it takes me 3-4 days to do everything, mixing, walking, pumping, walking, refilling, then more mixing, more walking, more pumping, & more refilling. Its SO HOT here in south GA right now, its brutal. Whatever it takes to get the peas to the finish line. While this barely works this year, next year I will have 5-10x the land to plant, and I HAVE TO get all this ironed out as soon as possible because I'm running myself into the ground trying to keep up right now... on top of all that, the peas are about 5 days out from first summer harvest so the storyline is about to get a LOT harder for me because I am also the picker and the sheller. God help me, I'm doing the best I can.

 

[5030]

After my YM2310 purchase I learned on this site to NEVER use ether on this tractor because it could break the rings.

The rings aren't the major issue as with broken rings it will still run (poorly). Bending the connecting rods is the bad actor ,because spraying ether into the intake, the either don't ignite when the injector is supposed to inject but when the either reaches the combustion point, regardless of where the piston is at in it's stroke so the either ignition can and will drive the piston down even if it's on the compression stroke but not over TDC, causing the weakest part ( the connecting rod) to bend.

Warm air is the best starting aid actually. Why Cummins uses a 'Mullion Heater' in the air intake. Warm air in the air intake contributes to the air temp in the combustion chamber and allows cold starting easier.

Back in the day when I had a 6.2 in my Fords pickup (terribly underpowered piece of junk), I always had a hair dryer handy to warm the intake air when cranking the engine. Warm air in the intake and it would always start right up.

 

[5030]

I used the phrase "we" in my OP. It was actually my father that sprayed all the ether. (Not laying blame, but that's the truth) I have never used ether on an engine myself. When I originally saw him doing it I said "You shouldn't use that" (because I drive a diesel pickup, I at least know its a big no-no for engines w/ glow plugs- but the tractor doesn't have glow plugs, so I didn't know enough to press the issue.) His reply was something like "when i was young my brother worked on diesels and he used ether, and it was fine". (Which was probably accurate, 40 yrs ago) I looked up ether use on diesels (after the fact) and found out that method was eliminated from standard practice like 30 or 40 yrs ago. He's 70.

I am desperate. I have sprayed everything w/ a 4 gal backpack sprayer twice now (its prime bug season, and w/o spraying its all a loss) and it takes me 3-4 days to do everything, mixing, walking, pumping, walking, refilling, then more mixing, more walking, more pumping, & more refilling. Its SO HOT here in south GA right now, its brutal. Whatever it takes to get the peas to the finish line. While this barely works this year, next year I will have 5-10x the land to plant, and I HAVE TO get all this ironed out as soon as possible because I'm running myself into the ground trying to keep up right now... on top of all that, the peas are about 5 days out from first summer harvest so the storyline is about to get a LOT harder for me because I am also the picker and the sheller. God help me, I'm doing the best I can.

Trying to wrap my head around spraying weeds with weed killer and spraying starting fluid into the combustion air intake on a diesel engine has to do with each other?????

 

[UrbannGuerilla]

Maybe injection pump timing is off. But keep spraying ether. Maybe that will eventually repair it

The injection pump was just rebuilt after this issue happened. We installed the rebuilt pump exactly as the old pump came off... where one sprocket has a white dot on it, and the other sprocket has a V that lines up with the dot. (We even took the rebuilt pump back once after the tractor still wouldn't start, just to be sure the rebuilt pump didn't have a problem. Rebuilder put it on a test bench and said everything is normal.) Also the lift pump is new, and the filters. We took the tube from the tank off to observe fuel free flowing out, and it wasn't a full tube worth of fuel - it was less a quarter tube worth of fuel coming out. It was difficult to blow air back into the tank so we used compressed air against the tube going directly to the tank, and it took a couple seconds, then we heard a pop of something that sounded like it broke loose, then bubbles in the tank. I don't know how much of the problem the fuel restriction was of the entire issue, but it certainly wasn't helping.

 

[WranglerX]

The injection pump was just rebuilt after this issue happened. We installed the rebuilt pump exactly as the old pump came off... where one sprocket has a white dot on it, and the other sprocket has a V that lines up with the dot. (We even took the rebuilt pump back once after the tractor still wouldn't start, just to be sure the rebuilt pump didn't have a problem. Rebuilder put it on a test bench and said everything is normal.) Also the lift pump is new, and the filters. We took the tube from the tank off to observe fuel free flowing out, and it wasn't a full tube worth of fuel - it was less a quarter tube worth of fuel coming out. It was difficult to blow air back into the tank so we used compressed air against the tube going directly to the tank, and it took a couple seconds, then we heard a pop of something that sounded like it broke loose, then bubbles in the tank. I don't know how much of the problem the fuel restriction was of the entire issue, but it certainly wasn't helping.

But does it start and run without spray bombing it....

 

[UrbannGuerilla]

But does it start and run without spray bombing it....

No sir it will not start on its own right now.

 

[ROUSTABOUT]

But you still have not checked push rods?

 

[Jerry/MT]

How many PSI should each cylinder average? We got about 250psi per. Compression is 17.1:1 , atmospheric pressure around 14.7 .. would be around 251psi.. right?

A brand new 17.1 compression ratio engine should give about 560 psig with a 14.7 psi ambient pressure. At 250 psi i doubt that you'd start that engine with that low of a compression pressure.

 

[5030]

Could be rings, could be a blown head gasket or even bent con rods from using either. Whatever it is, it needs to come apart, no choice in that matter.

 

[Mike1955]

Did I detect a slight note of sarcasm in your post? Before I got my Yanmar YM2310 I knew almost nothing about diesel engines. I had heard that ether can blow the tips off of the injectors from one person but have never heard it from anybody else. After my YM2310 purchase I learned on this site to NEVER use ether on this tractor because it could break the rings. Even though my tractor starts easily in weather above 45 degrees I might have been tempted to use ether in colder weather if I had not read here to not use it. I think it's too bad the OP has been using so much ether unless the engine is made to be able to use ether. I hope the OP didn't get bad advice from someone about ether use. In any case you made your point. But it seems to me that maybe you were a little harsh. I think the OP is desperate and I wish I could help.
Eric

No harshness here. When you have either and the machine responds, it’s mighty tempting to keep on. I do not own a can of either. I am not a diesel mechanic but I prefer them over gas for several reasons. We have all bought our lessons and all I can do is wipe the egg off our face and keep on. Heat to the intake from a blow hair dryer helps me inthe winter.

 

[Mike1955]

Could be rings, could be a blown head gasket or even bent con rods from using either. Whatever it is, it needs to come apart, no choice in that matter.

Epic I watched a utube with an engine that would not run. All the injectors were rusted up.

 

[UrbannGuerilla]

Ok.. an update. Got the tractor running!

Turns out the gear that drives the injector pump was NOT lined up properly according to the marks on the gears that line up together. Two marks WERE lined up, but they were not the CORRECT marks to line up together. What we think happened is that the fuel supply restriction at/in the fuel tank exit point is what caused the tractor to initially die and then not be able to start back up. Then we had the injector pump rebuilt, replaced the lift pump, searched for fuel leaks and/or air entry points, blew compressed air into the tank and broke loose some type of blockage or restriction in the fuel supply (I drained most of the tank contents and looked inside & removed a 8" plastic fuel can spout laying on the bottom of the fuel tank. It's not from us, and we've had this tractor for about 13 yrs!), pulled the injectors and turned the engine over to observe the injectors spray out in 3 opposing directions, we temporarily installed a straight fuel line from the fuel tank exit to an inline fuel filter, and a small 5-10 psi bullet push pump to create positive pressure to the lift pump (eliminating some of the fuel line system to try to narrow the problem area down) But because the injector pump drive gears weren't lined up properly when it was re-installed, that is what continued to keep the engine from starting after we cleared the fuel restriction because the injection timing was too far out of sync. We lined it up properly this evening and it started immediately on the first try. It was like the sound of angels singing when that thing fired right up.

 

[LouNY]

Spent my career working in the Heavy Truck manufacturing business. I worked for a long time in a factory that built class 8 trucks. Back in the day before the intense vertical integration, we installed several brands of engines in the trucks. Detroit Diesel, Catapillar, Cummins etc. One of the factory options in those days was ether injection. It was basically a system that provided a canister of ether mounted on the truck, and able to be injected with a switch from the cab to aid in cold starts. It was obviously more popular with fleets based in the more Northern cold climates. Not advocating ether by any means, just thought some might find this interesting.

Those system were designed so that it only released a metered amount of starting fluid, the proper procedure with those was to start cranking the engine over then tap the ether button, you could tap it a few times while the engine was cranking and sometimes even when it was doing a stumbling run.

 

[dstig1]

Late to the party but it is good to hear you figured out the immediate problem....BUT...you still have low compression that is going to have to get dealt with at some point, so I would plan to deal with that during the off season. Either re-run the test if you don't think you did it right, or plan on rebuilding.

 

[pmsmechanic]

I would venture to say that the compression test is ok. Compression tests are supposed to be done on warm engines. Since the OP couldn't get the engine running it was done cold. Therefor low compression. If the tractor started right up like he said the compression is good enough.

 

[UrbannGuerilla]

I would venture to say that the compression test is ok. Compression tests are supposed to be done on warm engines. Since the OP couldn't get the engine running it was done cold. Therefor low compression. If the tractor started right up like he said the compression is good enough.

I hope you are right on the compression, that would be the best possible outcome. Doing the test cold was the only way we could get any information at the time- but we will still be keeping a close eye and ear on everything from here on out just incase there are any other underlying problems that could develop further. It did start RIGHT UP. I mean, IMMEDIATELY. We were pretty thorough on trying to get all the air out up to the injector because we had taken a lot of things loose on the fuel supply trying to figure it out. It turned over one time and started.

 

[WranglerX]

Now its all about time.....

 

[pmsmechanic]

It did start RIGHT UP. I mean, IMMEDIATELY. We were pretty thorough on trying to get all the air out up to the injector because we had taken a lot of things loose on the fuel supply trying to figure it out. It turned over one time and started.

I've been thinking about this some more. If you cranked the engine a lot previous to finding out the timing problem there could be some diesel in the bowl of the piston. That would increase the compression to help with the immediate start. It'll be interesting to hear how it starts cold after sitting idle for a few days.

Also: What is your location? If you're deep south and the engine is always relatively warm compared to where I live in Canada then low compression would be less of an issue.

 

[Mike1955]

I've been thinking about this some more. If you cranked the engine a lot previous to finding out the timing problem there could be some diesel in the bowl of the piston. That would increase the compression to help with the immediate start. It'll be interesting to hear how it starts cold after sitting idle for a few days.

Also: What is your location? If you're deep south and the engine is always relatively warm compared to where I live in Canada then low compression would be less of an issue.

I’m in Mississippi. Hot now. You have a problem but once you find it be easy. I don’t think it’s a big problem.