I have a 1999 D6r. Always ran fine. Brought it into shop couple months ago and painted it and it's been sitting for about 2/3 weeks been moved around parking lot occasionally. Went to work it today and operator took it up on a side hill and called me said it was making noise. I got there and when you crank it I knocks only for a moment then stops but it smokes pretty bad. I'm certain it's fuel smoke. Turn it off then crank it back immediately it won't knock but if it sits a minute or two then it knocks only for three or four knocks then stops. Smoke never clears up. Operator said it knocked a little when revved all the way up but I was scared to rev it that high until further investigation. It only has 4500hrs or so. Never any major repairs. I thought possibly injector bad and it was loading cylinder with fuel. I cracked each line individually and it doesn't stop smoking. However when I cracked the second injector from the front it kinda blows air out beside the nut instead of fuel. When cracked all injectors seem to cause the enjoins to miss as they should. Took intake side boot off of turbo and it spins freely and there is no play in it. I have a video but it won't let me upload. I can email to anyone that might be able to help. Thanks
I was around a D7F that had the 3306 in it that had a stuck injector that was not firing. The cylinder had a knock pretty bad like something was coming loose inside. I would think it would be something simple like that. The experts should chime in shortly. This tractor is an early one with the throttle lever like the 6H ? If so , IMO they were the better 6R made.
Yes I'm leaning toward a stuck injector also but just not sure how to quickly diagnose which one IF however that is the issue. THANKS
One diagnosis is to work it a bit and take temps of the exhaust manifold. If you've got a dead hole it'll be cooler than the others. I assume all the valves are set right? No broken pushrods, rocker arms etc. Sounds like an injector though.
I doesn't have a miss like it has a dead cylinder. It sounds like it's running on all 6. Kinda afraid to run it.
If there's one that's not right it may show up at idle even. If one hole is running rich or lean you should be able to see it in temps. It's one non-invasive test anyway. I suspect you'll see a difference in the one cylinder you mentioned. There's still a hundred other options unfortunately. Perhaps one of the Cat gurus will add their .02.
I think the big clue is the air blowing from your #2 injector. The tip may have fallen out. It happens when they get overheated. How's the coolant level?
It was ran hot a month or so ago because of bottom radiator hose was leaking. Is there a way to definitely tell its the number two injector without pulling the injector? If not that's fine just curious before I pull it. Is there anything particular I need to know before pulling the injector?
If an injector did in fact come off what's the likelihood it ruined the piston, valves, and possible other things?
Pulled the second injector from the front. The tip is missing. Should I pull the head off and inspect it do you think it just sent the tip on through the exhaust?
Can you get hold of a borescope..? If so you can take a look into the cylinder via the hole where the injector fits. My thought would be that, depending on how large the broken piece was, it's most likely disappeared up the chimney. However it's a case of what other havoc has it wreaked on its way up there that you need to know.
I will try and find a boroscope. It's just the cap on the injector that has the small orifices in it that is misssing. The injector tip isn't broken off.
Can you post a photo of the injector so everyone can see it. The way you are describing it I don't think you have too much to worry about.
What's missing looks like a steel rod, about 1/4" x 1/2" long. Sometimes it will bend a valve, sometimes it will break up and go up the flue, sometimes it will embed itself in the top of the piston. At the very least, you need to do a borescope inspection. I'd advise mentally preparing yourself for pulling the head. Oh, and replace all the other injectors.
There isn't that much missing.
The injector on the top is one missing the little cap
I'd still go with the borescope if you can get hold of one. You actually need one with a flexible (rotatable?) end so that you can shove it down the hole then turn the end using the external control so as to enable you to look upwards at the cylinder head to see the condition of the valves and the head itself. Of course any marks on the top of the piston would be an indication that whatever fell out of the end of the injector has been crushed between the piston and the head but there's nothing like being able to see both sides.
Obviously there are marks on the top of the piston. I was able to see the head and valves but couldn't get good pics. Valves are all ok by head has a few indentions not as much as piston. I know in a perfect would I would just rebuild engine entirely but like everyone else am on a budget and don't want to spend if I don't have to. HONESTLY, DO I NEED TO PULL THE HEAD AND REPLACE PISTON OR WILL IT RUN FINE LIKE IT IS? Would like to hear everyone's opinion. Anyone experienced this or similar?
Nice photos. The biggest risk in a situation like this is that the valves have probably been hit. This puts stress on the stem and the next thing you know, the head falls off the valve and then you're definitely in for an overhaul . If it were my personal machine, I would be pulling the head, replace just the two valves in question, dig the bits of iron out of the piston crown, buff up the dings with a flap wheel and put it back together. Oh, and reman injectors. How hard do you want to spin the wheel of (mis)fortune? *Edit. And check for bent pushrods as well.*
Thanks for the reply. I have 6 reman injectors waiting to go in. Yes I plan on replacing all of them. Can I replace the two valves myself or would I have to send to machine shop?
It depends on what kind of tools you've got. There's nothing complicated about it; standard automotive style poppet valve and lap it in until you get a continuous grey band. The springs will be pretty strong though. An ordinary automotive spring compressor may not be up to the job.
Its not unheard of to replace just the piston or put a cylinder pack in that hole. But I would listen to the experts here not me.
The only question I have is whether at least one the photos of the piston crown and cylinder liner was taken with the piston at BDC so that any marks in the liner would be visible. That would be the determining factor (for me anyway) as to whether to go for a cylinder pack or not. I'm with CM on this one. So long as there is no damage to the liner dig the big chunks out of the piston crown and clean it up, new valves in that hole just in case, a set of injectors and Bob's your father's brother ..........
Clean the piston up with buffing wheel, two new valves in head and be fine? There was no items left in cylinder, I'm sure they went out the exhaust. And yes I am putting 6 reman injectors back in
TBH looking at that photo now you have the head off I'm fairly convinced that everything stayed in the cylinder. It looks to me like there are a number of pieces (of the injector I assume) embedded into the piston crown...... There was not a lot missing from the injector so I'm not sure anything went up the chimney at all. Crank the engine over until the piston is at BDC just to make sure there are no score marks on the liner. And even though there are no marks on the valves I'd still replace them for peace of mind.
I will put piston at BDC and check liner but there was not any pieces left in the cylinder or embedded in top of piston. There is a lot of ding marks but I can't find any shrapnel anywhere.
Yes. I think if the liner isn't damaged, you will be OK cleaning up the piston. The aim is to polish off any sharp edges that could create hot spots. Even though the valves look ok, they have both been hit, look at the marks in the piston around the valve pocket. By the way, you were well on the way to a head gasket failure anyway. See how the plastic water ferrules are melted from the previous overheating.
I've seen that phenomenon on coolant ferrules before and in many cases it was related to the type of coolant being used. When engines came into our CRC for rebuild you could generally tell who the customer was based on the condition of the head gaskets and ferrules because we knew which customers used what type of coolant. The worst was a property that used reccycled coolant (don't ask...) and they could never understand why their engines were always in such bad shape when they were torn down. I would suggest when you reassemble the engine that you flush the cooling system and fill it with 50/50 premix ELC.
Maybe it was just the photo, but some of the larger ding marks appeared to have pieces of the injector embedded in them. As CM pointed out, there are a lot of ding marks in & around the valve pockets so you can guarantee the valves were hit even though they are not badly marked.