Oil & Fuel BX2350 Running Rough and Smoking

[GA06BX2350]

First of all I would like to thank you guys for reading this post. Earlier this summer I got a bit careless on my BX2350. I didn't lock down the ballast properly, and laid my tractor on its side. I was able to switch if off after 10 seconds or so. After an hour with a winch and a tree, I up righted it. I let it sit for a few hours and then I started it up (a hard start), drove it to the shed. It smoked the whole way. After a few days I started it up again, it ran rough and continued to smoke. Since that day I've run a tank of fuel through it. It always starts off running rough at low RPM and smoking. At higher RPM (2300) it smooths somewhat, but still nowhere near where it should be and it still smokes. After 1/2 hour or so the smoke decreases, but doesn't disappear completely. At that point and time, if I decrease the RPM the smoke is almost entirely gone. It starts smoking again if you crank the RPM up again. Although it never runs 100%, there are times after it warms up that it seems to want to try. It also never completely stops smoking. I've tried draining the tank and flushing with fresh diesel, I've changed filters a couple of times, and I've also checked to see fuel coming out of the fuel lines at the injectors. Any suggestions on my next step? Injectors? Injector pump? I'm at a loss where to go from here. Thanks in advance for your help.

John

 

[Recoveryhill]

The recommended procedure once a diesel engine has been tipped is to loosen either the glow plugs or injectors before turning the engine over, to insure that no fluid is present, on top of the pistons. Diesel engines are high compression machines and liquid does not compress so something has to give. The worst that can happen if you rotate a hydro locked engine is to bend the connecting rods and or damage the pistons and or piston rings. Even the torque of a starter motor will be enough to do the damage. Only a small amount of liquid need be present to raise the pressure in the compressed cylinder to dangerous levels.

The most basic test for a diesel engine, since it is basically an air compressor, is to do a compression check on each cylinder. Each cylinder must be within tolerance for the specified pressure or fuel will not ignite properly since there is no ignition system. Compression creates heat to fire off the injector spray and it must be high enough to fully combust the fuel. Do this, or have it done and you will either get the bad news, or eliminate the likelihood of any severe damage and move on to other potential issues.

Sorry to jump to this possibility but a compression test will be like getting an X Ray on a damaged limb to find out if the bone is broken or you just have a bad sprain. Here's hoping your numbers are high and some silly thing is causing your machine to smoke and not deliver full power. A compression test is inexpensive either to do yourself with the proper gage or to have a qualified mechanic perform.

 

[GA06BX2350]

Sorry to jump to this possibility but a compression test will be like getting an X Ray on a damaged limb to find out if the bone is broken or you just have a bad sprain. Here's hoping your numbers are high and some silly thing is causing your machine to smoke and not deliver full power. A compression test is inexpensive either to do yourself with the proper gage or to have a qualified mechanic perform.

Recoveryhill,
Thanks for the input. Good news, bad news, progress is good. Of course I prefer good news. I did a bit of calling around to a local shop before starting it that first time they reported that it shouldn't be a problem to start is. Based on your input and other input I've gotten, that initial advice sounds like it may have been bad. Oh well! I'll stop by the parts store on the way home to see if I can get a compression tester. I've never used a compression tester and hope never to have a reason to do so again, so do you think an inexpensive one from Harbor Freight would suffice for a few uses. I know they are cheap, but I'm not sure how accurate I really need for this test. Thanks again for your help.

John

 

[GA06BX2350]

Ok. I picked up a compression tester at Harbor Freight that supposedly has an adapter for a Kubota. Now, I have a stupid question. How exactly do I do a compression test? My guess would be to:
1) remove all three injectors so that there's no chance the engine will try to run on only two cyclinders making things worse
2) select the correct adapter and place tester in injector hole
3) unplug the fuel pump so that fuel isn't flowing all over the engine
4) using key, turn engine over slowly to see if pressure is created and maintained in the cylinder

• Any suggestions, corrections, etc?
• If I remove the lines from the injectors, how do I remove any air in the line?
• Is there a way to test the injectors?

Thanks
John

 

[Recoveryhill]

Disable the fuel solenoid to insure no fuel enters cylinders if you are using the glow plug position for the gauge. If you are using the injector position, also disarm the fuel solenoid to prevent injector spray while testing. Remove all glow plugs, or injectors depending on where you are mounting the gauge. Take extreme care not to cross thread the gauge when attaching.

The engine should be warm before the test as this will result in higher readings. Crank the engine over with the starter until the pressure in each cylinder peaks, and record the value.

There is a target pressure for a new engine, a minimum pressure and a maximum allowable pressure differential between cylinders.

Cheap gauges may not be accurate and could read lower/higher than actual but the differential pressure should be reliable as the gauge will read the pressure evenly, even if slightly wrong.

If your compression is good and you want to test injectors, they will have to be taken to a qualified shop to do so. The extreme pressure of fuel being ejected from an injector nozzle is dangerous, will penetrate skin and cause severe injury.

 

[Recoveryhill]

I have a four cylinder engine in my L3700 and will give you the pressure values for that engine. I don't know which engine you have but the values for it should be very close.

My service manual lists an E2 and an E3 engine

Compression pressure when cranking with starting motor: E2 - 512 to 583 psi E3 - 470 to 540 psi (those are new factory values obtained with a professional gage.)

Allowable lower limit both engines: 370 psi.

Allowable difference among cylinders: 10% or less

Quote on procedure from manual:
1 Run the engine until it is warmed up
2 Stop engine and disconnect the 2P connector from the stop solenoid in order to inject fuel (Jinglish translates "in order to prevent injection of fuel?)
3 Remove the air cleaner, the muffler and all injection nozzles. (Tomas says muffler? I'd be tempted to try this without that step)
4 Set a compression tester with the adapter to the nozzle hole
5 Keep the engine stop lever at Stop Position (I don't have such a lever but disabling the fuel solenoid will do the trick)
6 While cranking the engine with the starter measure compression pressure
7 Repeat steps 4 through 6 with each cylinder
8 If the measurement is below the allowable limit apply a small amount of oil to the cylinder wall through the nozzle hole and measure again
9 If the compression pressure is still less than the allowable limit, check the top clearance, valve and cylinder head
10 If the compression pressure increases after applying oil, check the cylinder wall and piston rings.

Notes: Check the compression pressure with the specified valve clearance
Always use a fully charged battery for performing the test
Variances in cylinder compression values should be under 10%

So the key takeaways are that you need to make sure valve clearances are correct, your battery is fully charged and if oil boosts compression you have a ring or cylinder wall problem. If the oil doesn't help, you have a piston head top clearance, valve or cylinder head problem. A bent push rod will result in the top of the piston not reaching the required height in the cylinder to compress air to the required value. If your engine was running fine before the tip, depending on hours, your valves clearance should be OK but if you test low and oil doesn't raise pressure, adjust the valves and test again before you tear anything apart.

Here's hoping you see 500 or better across all cylinders and you can eliminate piston/cylinder/ring/head damage.

 

[GA06BX2350]

Recoverhill,
Thanks again for the wealth of information. I have the 3 cylinder diesel with a little over 250 hrs on it, but as you said, the values shouldn't vary too significantly. The step by step procedures are a great help as well, they seem rather straight forward and clear. Also, thanks for the warning about the injectors. I had heard as much previously, but it never hurts to hear it again. With the time change, I don't expect to have enough daylight to work on this until the weekend, still, I will keep you posted with my progress. Thanks again for the help.

John

 

[Recoveryhill]

Good luck with it and I sure hope you get satisfactory pressure on all three cylinders.

 

[JD 4520]

One procedural change to note...do not warm the engine due to the purpose and condition as that will exacerbate the problem. That is a procedure for normal conditions. Having said that, I realize you have already run the engine for a number of hours after the incident so its unlikely to cause further damage at this point. This caution is more of a note to others in the future.

 

[GA06BX2350]

Thanks again guys and thanks for the luck. I'll let you know how it turns out.

John

 

[GA06BX2350]

So, I got a bit busy with the kids today so it looks like the compression test will have to wait until tomorrow. Before I start this test, I did have a suggestion that I wanted to run past you guys. A friend of mine was a diesel mechanic in the military and when I told him I was going to do a compression test he suggested that I do a "blowback" test first. Apparently it's a rather common, quick and simple test. The general thought behind the test is that pressure takes the route of least resistance. On the compression stroke, if the exhaust pushes past the piston rings, then it will take the path of least resistance out of the crank case. If the oil cap is off then that route is generally the oil fill cap. Now, while it won't detect a problem with a particular cylinder, supposedly it will tell me if I'm having a ring leaking problem in general. My questions...since this is such a small engine will this actually work?
My thought is that this might catch a problem with rings, but not the pistons or connector rods. I appreciate your input.

Thanks,
John

 

[Recoveryhill]

Blowback would occur if you had a cracked piston, damaged rings or cylinder wall. You can't manage what you can't measure and I don't know any way of measuring the result of a blowback. A compression test will give you specific numbers for air pressure in each cylinder and if low, a method to guesstimate the location of the problem. You are correct in assuming that a bent rod, resulting in lack of sufficient piston travel in the cylinder will not create blowback. Again, I just hate to be the messenger but bent connecting rods would be a risk in any hydro-locked engine. The strength of the rods that transfer power from the combustion zone to the crankshaft are designed to withstand the pressure in the cylinder of a precise volume of compressed air. They are not designed to withstand the increase in pressure that occurs when there is liquid in the combustion chamber.

With the injectors out, you can also measure the depth of the piston face while at the top of it's stroke and compare to factory value. That's going to require a dial indicator though and even a relatively small differential will cause combustion problems so the measurement needs to be very precise. Mount indicator on engine with probe extending into cylinder. Rotate piston through full travel and note the travel number (height of stroke) and record. Repeat on each cylinder, mounting indicator in identical plane with probe arm unchanged in position. If any piston travels less distance, it's a rod. For this you would rotate engine by hand only, not with the starter motor.

If you have the specified pressure in each cylinder though, that and anything else related to the combustion chamber is not your problem.

Were it me, it would be out with the injectors and in with the pressure gauge. This will define your conditions in each separate cylinder.

 

[GA06BX2350]

Understood. Thanks!

John

 

[GA06BX2350]

So today I finally got the chance to work on my tractor. Since I was going to have to remove the injectors anyway I decided to go ahead a replaced them (got a great deal, 3 for $135). I removed the first injector and tried to screw in the compression tester adapter........it doesn't fit and the store is closed for the day. Still, it wasn't a total loss. After removing all the injectors I noticed that one of the cylinders had hard buildup in the hole where the nozzle fit's into the cylinder. In this indicative of anything? Could it be that the injector isn't able to spray a good pattern so the engine isn't running correctly? Any suggestions on how to remove the buildup? Thanks for the reply. I'll also let you guys know about the compression as soon as I get a new tester.

Thanks,
John

 

[Gator6x4]

When I read your post I starting thinking someone told me the Harbor Freight Diesel Compression checker used the GLOW PLUG HOLE. So I goggled it and sure enough I still have a little creditable memory. Please read the information in the attached. Compression Test Adapter - OrangeTractorTalks - Everything Kubota. Good luck.

 

[Recoveryhill]

After removing all the injectors I noticed that one of the cylinders had hard buildup in the hole where the nozzle fit's into the cylinder. In this indicative of anything? Could it be that the injector isn't able to spray a good pattern so the engine isn't running correctly? Any suggestions on how to remove the buildup?

John, The build-up is carbon from un-burned hydrocarbon, fuel or oil. I can't say whether or not a faulty injector would produce this but if there is considerable buildup of this material in the combustion chamber it is going to affect your compression test. My paranoid self thinks.....low compression due to bent connecting rod causes partial combustion of injected fuel, lack of power and smoke. You would see low compression. Hmmmm....significant build up of material in the combustion chamber reduces volume of chamber and raises compression even if piston travel is reduced. (I probably think too much).

I'd just go ahead with the compression test and pay close attention to the affected cylinder. If compression is good, there must be a solvent that can be injected into the cylinder to help dissolve the carbon. Make sure if you add any solvent that the glow plugs and injectors are OUT of the block so as not to have accidental combustion and to allow the crud to blow out. Since you are using the glow plug port for the gauge make double sure the fuel is shut off to the re-installed injectors. If you do have low compression in that cylinder, regardless of the carbon, don't forget to try injecting a bit of motor oil into the cylinder and check compression again. Broken rings would allow crankcase oil into the upper cylinder and if a shot of oil raises compression, look to sleeve, piston or rings. In any case, after I got the carbon out of the cylinder I'd check compression yet again unless it's low to begin with even with the carbon up there.

Perhaps someone else has direct experience with either the cause for the build-up or how to remove.

 

[Recoveryhill]

OK then, I'll continue:

Carbon removable from static engine parts: Chlorinated brake cleaner (tetrachloroethylene) will remove carbon from substrates. (harmless to aluminum parts)

Carbon build up removal in a running engine: Seafoam

Still hoping those compression numbers are right in line?

 

[GA06BX2350]

Thanks for all your help so far. The compression testing kit from my local Harbor Freight store had the same item number as the one mentioned above but looked totally different. It even looked different than the one at HF online. Nothing in it fit the hole for the glow plug or the injector. So, I finally broke down and took the tractor to the local dealer. Unfortunately you were right, it is losing compression on the number 3 cylinder (closest to the front of the tractor) and there is a lot of carbon build up in that cylinder. They called me this morning with a series of estimates to fix it. They feel confident that it's not the rod or valve. They think it's a cracked ring but just in case they want to send out the head for testing. If it's a cracked ring they will fix it for ~$1200, labor is major cost as they estimate 10hrs at $80/hr. If it's the piston itself the cost is ~$1450. If the head is bad, the cost for the piston, ring, and head is ~$2650. An entirely new engine, which is everything, would be around $4000. The mechanic said he truly thought it would be the ring, but he's not 100%. I'm already in to them for $200. To me that all seems a bit high, but then again I've never had this sort of work done before. I would love to have someone elses perspective on this.

As always I appreciate the input.

John

 

[GA06BX2350]

By the way, I've asked for the exact compression numbers but the mechanic didn't have them in front of him. I'll post them when I get them. One thing that still confuses me is that there was no blowback. If there was no blowback wouldn't that make the ring / piston an unlikely culprit.

Thanks,
John

 

[rbarker]

Thanks for all your help so far. The compression testing kit from my local Harbor Freight store had the same item number as the one mentioned above but looked totally different. It even looked different than the one at HF online. Nothing in it fit the hole for the glow plug or the injector. So, I finally broke down and took the tractor to the local dealer. Unfortunately you were right, it is losing compression on the number 3 cylinder (closest to the front of the tractor) and there is a lot of carbon build up in that cylinder. They called me this morning with a series of estimates to fix it. They feel confident that it's not the rod or valve. They think it's a cracked ring but just in case they want to send out the head for testing. If it's a cracked ring they will fix it for ~$1200, labor is major cost as they estimate 10hrs at $80/hr. If it's the piston itself the cost is ~$1450. If the head is bad, the cost for the piston, ring, and head is ~$2650. An entirely new engine, which is everything, would be around $4000. The mechanic said he truly thought it would be the ring, but he's not 100%. I'm already in to them for $200. To me that all seems a bit high, but then again I've never had this sort of work done before. I would love to have someone elses perspective on this. As always I appreciate the input. John

Sorry to hear that it's internal damage, that's a shame. Now you really have to play crystal ball and try to guess what they are going to find once they get it opened up. The prices quoted don't seem too out of line to me but as I got closer to the price of a new motor I would lean heavily in that direction. Too bad you won't know for sure until they get pretty deep into the project.

Good luck and hope for the best!

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