When you changed out the glow plugs, the cylinder which was smoking a bit had developed some carbon buildup and its been chipped out a bit when that glowplug was removed. This caused a hot spot in the cylinder which is now pinging. It ought to heal by further carbonizing or it will clean itself out. Stick a small mirror down a hole at look around to see the localized glow plug site. Or, pull the head and clean it up.
Help!! Loud Engine knock after changing glowplugs
- Thread starter OldBulldogger
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OP
OldBulldogger
Bronze Member
I appreciate everyone's input here and all the help.
Regarding "zzvyb6" post about a hot spot in the cylinder which is now pinging, this would seem to make sense since the only variable in the situation was pulling out the old glowplugs and adding new ones. Obviously I disturbed some carbon and I believe they were original - 22 years old.
How loud is the pinging you described supposed to be? I was about 15 feet away from the tractor after I had initially started it and ran it about 5-8 minutes when I heard the new noise. It was loud enough to notice over the normal sound of the engine and it was instantaneous. Do I stick the mirror down the hole of the glowplug and if so, what would I see that would indicate a hot spot? How long does it take to "heal" itself? Admittedly, I am new to this.
I am cautious as to running it for long in fear that it is a rod bearing, wrist pin, or other. Any way to rule that out if the above is true?
Regarding "zzvyb6" post about a hot spot in the cylinder which is now pinging, this would seem to make sense since the only variable in the situation was pulling out the old glowplugs and adding new ones. Obviously I disturbed some carbon and I believe they were original - 22 years old.
How loud is the pinging you described supposed to be? I was about 15 feet away from the tractor after I had initially started it and ran it about 5-8 minutes when I heard the new noise. It was loud enough to notice over the normal sound of the engine and it was instantaneous. Do I stick the mirror down the hole of the glowplug and if so, what would I see that would indicate a hot spot? How long does it take to "heal" itself? Admittedly, I am new to this.
I am cautious as to running it for long in fear that it is a rod bearing, wrist pin, or other. Any way to rule that out if the above is true?
MD09
Bronze Member
Diagnosing a noise over the internet is a bit tough.
The soot in the center cylinder is the location of your issue.
If some Carbon broke off the piston it would quickly find it way out in the form of soot. I have never expirenced a ping or a knocking noise from loosing a build up of carbon.
The Fact that this happend rather quickly points to a Mechanical issue,, I would suggest pulling the valve cover and inspecting the rockers or springs on the center cylinder. a broken spring will cause a tap and it might not allow the valve to get stuck in the cylinder when the piston come up. It might be open just a bit and the piston/compression closes it. This might also cause a rough running indication but not always. Some to think about diesels are fairly tollerant of bad parts when you do not have a load on them, a bad injector coudl be missed, same with a valve problem or for that mater an injector. Once you put a load on it the issue will magnify if self in the form of lost power.
Injector are mechanical and there could be a problem with the center cylinder. One suggested using a long rod to see if you can isolate the sound isolating it to either upper or lower could help point you int he right direction
If you are truely worried about a rod bearing dor the oil pan and look at the connecting rod of the offending cylinder. If t is bad enough to cause a knock it will move. Also if you rev the engine up does the knock change tone? or just get louder? Also when draining the engine oil drain it thru a piece of cloth, if there is metal in the oil it will show up inthe cloth, this would indicate a bearing issue crank or connecting rod most likely.
Big end connecting rod bearings tend to change tone when rev'ed up from a knock to more of a metal on metal sound.
Valve cover is a simple place to start. Pulling the pan is also fairly easy.
Idea, swap the injector from the center cylinder to one of the others and run it for a few minutes, if the soot follow the injector you have you culprit if it doesn't you have ruled another part out.
The soot in the center cylinder is the location of your issue.
If some Carbon broke off the piston it would quickly find it way out in the form of soot. I have never expirenced a ping or a knocking noise from loosing a build up of carbon.
The Fact that this happend rather quickly points to a Mechanical issue,, I would suggest pulling the valve cover and inspecting the rockers or springs on the center cylinder. a broken spring will cause a tap and it might not allow the valve to get stuck in the cylinder when the piston come up. It might be open just a bit and the piston/compression closes it. This might also cause a rough running indication but not always. Some to think about diesels are fairly tollerant of bad parts when you do not have a load on them, a bad injector coudl be missed, same with a valve problem or for that mater an injector. Once you put a load on it the issue will magnify if self in the form of lost power.
Injector are mechanical and there could be a problem with the center cylinder. One suggested using a long rod to see if you can isolate the sound isolating it to either upper or lower could help point you int he right direction
If you are truely worried about a rod bearing dor the oil pan and look at the connecting rod of the offending cylinder. If t is bad enough to cause a knock it will move. Also if you rev the engine up does the knock change tone? or just get louder? Also when draining the engine oil drain it thru a piece of cloth, if there is metal in the oil it will show up inthe cloth, this would indicate a bearing issue crank or connecting rod most likely.
Big end connecting rod bearings tend to change tone when rev'ed up from a knock to more of a metal on metal sound.
Valve cover is a simple place to start. Pulling the pan is also fairly easy.
Idea, swap the injector from the center cylinder to one of the others and run it for a few minutes, if the soot follow the injector you have you culprit if it doesn't you have ruled another part out.
MD09
Bronze Member
PS diesels ping due to timing issues.
Old fuel might also becausing your problem might have a blockage in teh # 2 injector. you did say it was cold out.
Old fuel might also becausing your problem might have a blockage in teh # 2 injector. you did say it was cold out.
JerryK
Elite Member
- Joined
- Feb 21, 2004
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- Tractor
- Mahindra (2011)5035 HST TLB & (2016)2555 HST Cab & (2017)1526 HST(2018)Cub Cadet Pro Z 154L (1991) Caterpillar E70B
Me, I think any carbon you dislodged by changing the glow plugs would quickly be cleared out of the cylinder. If you had a real bad injector and that jug wasn't firing right, I might go for the carbon thing. Glow plugs don't have anything to do with carbon buildup, so putting a new one in wouldn't make that jug fire any different after it is running. You could need to check your valve train [ like it was suggested above ] and adjust it while you have to cover off. And you might just be hearing something that was there all along, but since you f'd with the motor you are more sensitive to the sounds. If the valve train looks good, run it moderatly for a couple hours at lower than wide open...and see if the sound goes away. Starts getting worse or you notice cast iron block pieces flying thru the air....shut her down... :") Probably just an injector... [ good luck ]
OP
OldBulldogger
Bronze Member
Okay - learning as I go here. The fuel I am running is the same tank I have been running on since getting it home. Was about 3/4 full, now down below 1/2 to 1/4. Don't think I have moisture issues or gelling.
If I have a blocked or partially blocked injector, wouldn't it run rough?
Mine is still running smooth, not rough, nor hesitating however since hearing the noise, I have not run it for more than about 15 minutes total off and on. It has not left the shed so I can't speak for power however when revved up, all hydraulics are quick to respond under load. I did pull the new glowplugs back out to check and they seem fine other than the center cylinder having more soot than the others. It sounds more top end just by listening but it is hard to tell. Any thoughts?
If I have a blocked or partially blocked injector, wouldn't it run rough?
Mine is still running smooth, not rough, nor hesitating however since hearing the noise, I have not run it for more than about 15 minutes total off and on. It has not left the shed so I can't speak for power however when revved up, all hydraulics are quick to respond under load. I did pull the new glowplugs back out to check and they seem fine other than the center cylinder having more soot than the others. It sounds more top end just by listening but it is hard to tell. Any thoughts?
JerryK
Elite Member
- Joined
- Feb 21, 2004
- Messages
- 3,240
- Location
- Vanderbilt, Michigan, USeh?
- Tractor
- Mahindra (2011)5035 HST TLB & (2016)2555 HST Cab & (2017)1526 HST(2018)Cub Cadet Pro Z 154L (1991) Caterpillar E70B
Injectors are supposed to squirt diesel into the chamber at a certain time. The injection pump applies pressurized diesel to the injector at a certain time, at a certain pressure. The injectors are supposed to stay closed.... untill the injection pump applies enough pressure to that injector to 'open it up' and squirt into the chamber. Injectors are set to a certain pressure, and over time they can become uncalibrated, gumed up, or leak. This can allow diesel to be squirted into the chamber at the wrong time....and cause knocking. Only way to find out is to pull the injectors and take them to a diesel place to check. I had a bad injector on my 2240, and instead of messing with it, just threw in three new injectors. But, unless you know that that is your problem, kind of an expensive shot in the dark. The new diesel, Ultra Low Sulphur Diesel [ ULSD ], has alot less sulphur in it... the sulphur they took out used to lube the injection system. You should use a diesel suppliment like Power Service Diesel Fuel Suppliment or a simular additive to each tankful.
art
Super Member
It does seem strange as to how it started!
Things that could be done, undo the air intake and take a spray bottle of water at 1/3 throttle and don't flood the engine with it, not enough to die but it will get rid of the soot.
While running if you loosen the injector lines to relieve the fuel pressure chances are the knock will go away and you will know which cylinder is causing the issue.
With some engines I've actually seen mechanics start taking them apart thinking a rod bearing was gone when it was just an injector not spraying into the proper area on the top of the piston.
It might just be an injector!
Things that could be done, undo the air intake and take a spray bottle of water at 1/3 throttle and don't flood the engine with it, not enough to die but it will get rid of the soot.
While running if you loosen the injector lines to relieve the fuel pressure chances are the knock will go away and you will know which cylinder is causing the issue.
With some engines I've actually seen mechanics start taking them apart thinking a rod bearing was gone when it was just an injector not spraying into the proper area on the top of the piston.
It might just be an injector!
Caliche
Bronze Member
If it was my tractor, while I had the glow plugs out anyways, I would have hit the starter and listened for the tap. With the glow plugs out there will be little compression and the engine will turn over faster than with full compression. If a rod, piston, valve...... problem it should be audible.
