Sudden clunking/blue smoke diagnosis

[evofxdwg]

I was using my 1610D today moving some dirt (for about an hour) and engine suddenly started making a loud clunking sound at, i think, the rotation rate, accompanied by slightly rougher running, a "miss" like its running on 2 cyls, and later noticed a bit of translucent blue smoke coming out of exhaust. I idled it down immediately. When added throttle the clunking gets louder. I shut it off for a few minutes. I checked the oil and temperature, which were both fine, then started it back up - not as loud initially but throttle up and clunking gets loud again. I just drove it back to the shed and shut off. I didn't check it under load to see if the power was down significantly for fear of further damage.

Im thinking rod bearing, broken rod, broken ring, or a valve or valve train failure keeping one exhaust valve open (can this happen?). Or maybe im fooled by the symptoms and its a head gasket. Does a rod bearing start making very loud noise all of a sudden?

Need armchair diagnosis and next steps to diagnose. Ive wrenched on a lot of gas engines but not diesels.

 

[kenmac]

can you tell if the noise is comming from around the bottom area of the motor ? If so may need to pull the oil pan & take a look

 

[Streetbully572]

Yep, pull the pan off!!

 

[alvanko]

I had a 3 cyl Kubota that would suddenly start knocking and I thought the same thing, but it was an injector that quit woriking. Possibly water. Once I shut it off, changed the fuel filter, all was well.
The same symptoms as you describe.
Might want to check that first before pulling the pan........

 

[normde2001]

"Im thinking rod bearing, broken rod, broken ring, or a valve or valve train failure keeping one exhaust valve open (can this happen?). Or maybe im fooled by the symptoms and its a head gasket. Does a rod bearing start making very loud noise all of a sudden?"

Yes. Eliminate air/fuel problems with operator maintenance.

 

[winston1]

If you can't trace knock to particular cylinder by sound you might pull the exhaust manifold and see which cylinder is blowing the smoke. Probably going to end up pulling it anyway.

 

[clemsonfor]

The problem with the injector diagnosis is that you need to run it again and crack the lines to see if there is a difference. This will cause more wear if its a bearing or cyl. Any you could think you found it when the offending cyl does not change, as it may have broken rings etc as well whick would cause it not to fire. Or you could replace fuel filter and take the head and injectors to a deisel shop and have them loookk them over to see if there is a problem. This will cost some $$ though. Id pull the pan as all it is , is like a 1/4 inch steel plate with a drian plug in it. real easy to see stuff id think and wont take 15 mins to get it off. Im thinking rod bearing personally, and you dont want to gall that crank if that is what it is.

But im no pro mecanic i just listen and learn and tear into stuff as needed.

 

[evofxdwg]

Thanks for the input from everyone.

I had the fuel filter/water problem several months ago and fixed it with a fuel filter change. The tractor has been run several hours since then with no problems. I havent studied how the injectors work but they have to be mechanical so i suppose a failure there could cause a clunking noise.

I think i will pull the pan first. Since its a 4wd, im assuming its a little more trouble as i assume i have to remove the drive shaft to the front.

Will see when i get a round tuit and report back here.

 

[Hass]

I have 357 hours on my 2007 Kioti CK20HST with a FEL & BH. I had a similar problem about a week ago. I was moving some dirt with the FEL and started to notice a few puffs of blue smoke. Within 2 minutes it was a constant stream of blue smoke from the exhaust along with the engine running rough like it was missing on 1 cylinder.

I loaded the tractor on the trailer to take it back to the dealer the next day. Come to find out the warranty ran out less than a month ago. They changed the fuel pump (didn't fix it). After a few minutes of running, it cleared up instantly and the engine smoothed out.

Thinking the problem was fixed, they went to raise the FEL and nothing happened. No hydraulics at all. Dealer told me I needed a new hydraulic pump. So taking their advice I ordered a new hydraulic pump, but opted to change it myself ($300+ for labor, no thanks).

After I got home I pulled the old pump. However, it appears the old pump is just fine. So I started looking into the gearbox the pump mounts to. When you crank the engine, the gears do not turn. So I pulled off the gearbox and found the shaft that drives the gearbox for the hydraulic pump sheared. This shaft also has what appears to be lobes for the fuel injectors. I'm not sure as to what this shaft is called. Now things are starting to make sense.

This is what I'm thinking happened... The shaft had a defect in it which caused it to slowly crack over time. Eventually it cracked enough that the shaft started twisting causing the injection timing to be off for the aft cylinder (reason for blue smoke and rough running engine). Finally when the shaft failed (torsional failure), the aft cylinder no longer was getting fuel (no more smoke & engine smoothed out) and the hydraulics stopped working.

One other thing I have noticed over the past few months is the my tractor seemed to be loosing power while driving and operating the FEL & BH. I never thought anything of it until now.

Tomorrow I'll be taking my broken parts to the dealer to try and order a replacement. I'm afraid this is going to be easy or cheap. I'll post more later.

 

[Hass]

Here is a picture of the section of the shaft that sheared off. The splines connect to the gearbox that goes to the hydraulic pump.