Bad Knocking Sound Coming from 2910 Engine !!??

[Don_Curley]

Well, I've put 6.5 hours on my new 2910 and I ran into what I hope is not a major problem. Yesterday, while doing some "moderate" work with the tractor (primarily loader use and smoothing-out some piles of loose dirt), a bad knocking sound developed from the engine area. I was running the tractor at about 1,800 to 2,000 RPM, had just dumped a load of soil, and was backing-up a short distance when this happened. Now how can I descibe the noise? If you consider that the diesel engine sounded something like a bunch of marbles rattling around in a can, this knocking noise was much louder, was fairly low in tone, and was going much slower ... sort of like ... KNOCK, KNOCK, KNOCK, KNOCK (etc.). You could not only hear this knocking noise, but you could also feel it in the seat of your pants as well. I immediately stopped, reduced the throttle, took it out of gear, and turned-off the engine (and by the way, engine temp was just fine). Even though I had previously checked out the fluid levels upon delivery, I rechecked the engine oil, and it was clean, "good smelling", and at the proper level. A quick visual check of the engine, undercarraige, and the rest of the tractor didn't turn up anything suspecious. After a few minutes, I restarted the engine and after approximately 10 to 15 seconds, the bad knocking sound returned. I again shut everything down and waited another 15 minutes. When I restarted this time ... nothing. Everything sounded OK and I proceeded to use the tractor for the same kind of work for another hour or so, with no repeat of the bad knocking sound. Does anyone have a clue as to what this sound was or what it might point towards (in terms of an impending failure)?? I am no master mechanic, but I have been around a lot of engines (although not diesels), and if someone asked me what I thought that sound was, I would have probably said connecting rod, or perhaps a piston, or the crankshaft ... it was that bad. Has anyone else experienced this sound? Although I plan to follow-up with my dealer on this, does anyone have any diagnostic suggestions to help get to the bottom of this? Or should I relax and only worry about this if (and when) it ever happens again?

Don

 

[looch]

<font color=blue>Or should I relax and only worry about this if (and when) it ever happens again?</font color=blue>

If you can do that, you have more self-control than I. Loud knocks coming from the engine = immediate panic for me.
The only similar experience I've had was with my Ford Ranger pick-up. Same thing, "bowel-shaking" knocks after about 5000 miles. Turned out cylinder #6 was machined too big. They replaced the engine under warranty. I wouldn't jump to conclusions, though. Might be serious, might be something minor. I would definitely have it checked out before firing it up again, though.

Sorry I couldn't be of more help.

Paul

 

[glennmac]

In my experience, knocking noises are always bad. Maybe not real bad, maybe something minor just loose, but definitely bad. It is not normal. Have it checked right away. Dont risk damage to your brand new machine.

 

[rbargeron]

I'll chime in too - get the dealer to come listen to it and have him get the Kubota zone rep to come listen to it. He'll need to authorize a warrantee tear-down anyway so the sooner he hears it, the better. In reading your post, the image I got was maybe a loose bolt backing out somewhere inside the housings - maybe getting machined off as it knocks - UGH !!.

I'll bet Kubota will show real interest in this - they don't often have assembly-quality problems so should be eager to get to the bottom of it.

 

[Von]

Re: Bad Knocking Sound Coming from 2910 Engine !!?

This could also be caused by an air leak at a injector nozzle. Could be a bad o-ring that is allowing some air in when it heats up. Just something else to think about.

 

[Alan L.]

Re: Bad Knocking Sound Coming from 2910 Engine !!?

My guess is that you'll take it in and the Kubota rep won't be able to "duplicate the problem".

Alan L., TX

 

[woodstock]

Re: Bad Knocking Sound Coming from 2910 Engine !!?

AlanL,
Did I detect a tone or experienced sarcasm.

Don
I don't have diesel engine experience, but could it be a piece of carbon? I once experienced this with a gas engine.

Thankfully its under warranty or else it would be
Knock Knock
Who's there?
Pain
Pain who?
Pain in the wallet.

Good Luck and keep us informed.

Winnipeg, Manitoba

2001 BX2200 All Kubota FEL, Tiller, box blade, blower w/elec shute, 60 mid mt deck, Ag tires.
Grey market B7000 w/Tiller (120 hrs)
1984 JD 316 after 687 hrs.

 

[ronjhall]

Don
From your description I would have to go along with Von’s thoughts. Probably something in the fuel system. One cylinder was not getting fuel properly. May still require warranty work./w3tcompact/icons/frown.gif Hope it’s something dealer can find easily./w3tcompact/icons/smile.gif

 

[Don_Curley]

Thanks everyone,

I am contacting my dealer this morning on the knocking problem ... I do hope it's simply the fuel issue that Von & Ron mentioned and not something more sinister. (And it's funny, when I was descibing the "KNOCK, KNOCK" sound in my original post, I wondered if someone was going to come up with a knock knock joke ... thanks woodstock).

I'll let you know what the dealer does (since it's a 320 mile round-trip for them to my location) and then what it turns out to be (assuming it can be duplicated and then diagnosed).

Don

 

[Alan L.]

Re: Bad Knocking Sound Coming from 2910 Engine !!?

A little sarcasm, from experience. Hopefully the problem will be detectible in this case.

Alan L., TX