Deere 2720 Smoke issue at startup

[chrisbowers8]

Hi everyone,

Before I go and pull the head off of this thing I wanted to see if there were any other ideas. My 2720 is absolutely belching out smoke at cold start and kinda rumbles a bit, almost like it's not running on all cyls - it smells like unburnt diesel. It does clear up once up to operating temp and the tractor seems to run just fine with plenty of power. My first thought was stuck injector. I pulled the injectors, they didn't look great, at least to my untrained eye, so I replaced them. No effect.

Then I checked the valves - they are all within spec and no oil is getting by the valve seats. It "Smells" literally like a fuel issue, but I'm not sure what else it could be? I was thinking of pulling the head to check for scoring, like if there was a bad ring where oil was getting by, but it doesn't smell like burning oil to me - it smells like fuel. Any thoughts would be appreciated.

 

[Roadworthy]

Before tearing the engine down try checking the air filter. If it's clogged from a summer of dust it will be getting too much fuel for the amount of air coming in.

 

[Harry in Ky]

I wonder how long does it take to clear up? It runs fine with usual power? I can't see where pulling the head is going to show you much. If you have ring problems you will need to go much deeper than that, and if there's nothing scary in the motor oil, I wouldn't go there just yet.

Injectors are a "maybe", but you've changed them. I assume you've considered glow plugs as well? One cold cylinder on start up will make for some rough running and rattling, at least for a few minutes.

I'd consider working through a compression test before pulling the head.

 

[chrisbowers8]

I wonder how long does it take to clear up? It runs fine with usual power? I can't see where pulling the head is going to show you much. If you have ring problems you will need to go much deeper than that, and if there's nothing scary in the motor oil, I wouldn't go there just yet.

Injectors are a "maybe", but you've changed them. I assume you've considered glow plugs as well? One cold cylinder on start up will make for some rough running and rattling, at least for a few minutes.

I'd consider working through a compression test before pulling the head.

It clears up after 3-4 mins but it absolutely smokes out my barn. Air filter is new so it’s not that. Haven’t checked the glow plugs but I will do that. This happens at 95 degrees or 25 degrees though. Doesn’t go away til it’s up to full operating temp.

 

[Harry in Ky]

I admit that sounds like more than a bad glow plug. This is a relatively new condition I take it?

Does it have a lot of hours on it and/or any more blow by than before you noticed this?

I guess the injection pump could be suspect as well, that type pump has been know to produce some unusual symptoms.

I would look into locating the necessary parts/pieces to run a compression test before I would pull the head. If you just open it up and don't see anything obvious, then what? Put it back together and try again? Tear it down further? You could be looking for something that isn't there.

 

[chrisbowers8]

Only has 650 Hours. Not sure about blow by - I mean if that’s the cause then I guess but I don’t know.

 

[Harry in Ky]

Blow by isn't a cause of anything. It's merely an indicator. If you have piston skirt/piston ring/cylinder wall scuffing/scoring, or just natural wear, the blow by increases. All that affects compression. That's one reason why a compression test can help identify differences in performance between one cylinder and another. If the compression is more or less even between all cylinders, then you can lean towards fuel delivery, timing, or some other reason for the poor performance and not tear the engine down only to find nothing really wrong.

 

[chrisbowers8]

Blow by isn't a cause of anything. It's merely an indicator. If you have piston skirt/piston ring/cylinder wall scuffing/scoring, or just natural wear, the blow by increases. All that affects compression. That's one reason why a compression test can help identify differences in performance between one cylinder and another. If the compression is more or less even between all cylinders, then you can lean towards fuel delivery, timing, or some other reason for the poor performance and not tear the engine down only to find nothing really wrong.

Right, sorry what I meant was the blow by is the cause of the smoke - fuel/air making it past the rings.

 

[Beaver Cove Deere]

Send in an oil sample. That will show any dilution to the engine oil if it has raw fuel in it.

 

[Tx Jim]

How long since this tractor has been worked hard? Diesel engines were designed to work not putter around. I think you should perform a compression test on the engine before even considering disassembly of this engine.