I think you have already seen that I am putting some time and effort into this old school grader but that it has been giving me the resources to survive these difficult times. I repair it myself because in these places the mechanics are very expensive and there are very few good and reliable ones ... so I prefer to investigate, in this great forum mainly and execute on my own. Engine Cummins 6CT 8.3 On this occasion I have decided to stop the machine in the middle of a job because for a couple of years that I bought it I have been feeling that cylinder #6 does not contribute to the engine thrust (it did not work even, black smoke came out when accelerating and the output to the manifold exhaust was always wet and with black drops). I started with the simple test of releasing each injector to determine how much each one contributes and clearly in cylinder 6 there were no changes in the running of the engine. I changed for a new injector and everything remained the same, adjust the valves and everything remained the same, then I plucked up the courage and took out the cylinder head and took it to a place where they are specialists in rectifying engines, they only found gaps in the guides and seals but They assured that there were no problems in the seal of the cylinder 6 valves. Then and with great difficulty, I managed to loosen and lower the sump little ( Will it be possible to get it out of this machine?) to remove the piston, which seemed to be responsible for the failure, however the piston was not broken nor the rings, all that was in order ... But I could see that the cylinder 6 liner was with a layer of rust or scale on the top, I remember the previous owner telling me that it had been a year without making it work. Here is a photo of the shirt and any of the other cylinders that work well. My questions are: Is it the cause of the cylinder that does not ignite? How did that get on the shirt? Thanks and cheers from Chile Cesar
You've been leaking coolant into the cylinder for a long time. My guess is, liner cavitation . If you have access to the rod cap screws, you should be able to extract the liner. That should allow you to do failure analysis of the liner itself, plus you'll be able to see the adjacent liners exterior. If you can, please post a pic of the entire liner top. We're looking for any place that has a black spot, a low spot or burn mark leading to a coolant passageway. If it turns out to be a pitted liner, a simple liner kit will clear it all up. Please post pics when able
@funwithfuel ,Thanks for your interest to help me, I'm on my way to the machine and I'll take the photos. Do you think this residue on the liner has caused the cylinder failure? Can compression escape through these small reliefs? Cesar
Yes, compression loss and coolant intrusion.
What does that piston and rings look like? You said it had sat for a year, it's possible it got water, mice ****, etc into that cylinder and rusted up. Has it been running antifreeze, and what type? has it been using any coolant?
Aha!!! Without much effort I have managed to remove the cylinder liner and I think that the coolant tried to enter through several points !!! I think the next step is to put on a new shirt and rings. Any advice? How to avoid this failure in the future? Apparently here the compression escaped, this means that while the machine was working the diesel was incorporated into the refrigerant and while it was sleeping the refrigerant entered the cylinder ??? I appreciate your forensic opinions. Cesar
We call that liner cavitation. The primary cause is poor coolant maintenance. The secondary cause would be poor coolant flow. I would inspect your water pumps impeller blade. Also check the area immediately behind the pump. Make sure the is no significant wear or damage to either. Anything greater than an 1/8 inch would be considered bad.
Look at the next liner through the deck opening where #6 was at. If it looks like 6, you'd better pull it now, rather than wait a couple weeks for it to fail on all your work and investment.
Folks, I'm going to put all the new liners on. Now the issue is: I tried to remove liners number 5 and number 4 and there is no use, they are very tight and do not move a millimeter. Can you advise me something to help with the extraction process? Cesa
Maybe jack it up and out with a bottle jack, being careful not to catch the block.
Good economy to replace them all. Google liner pullers to get some idea of what works. Doesn’t have to be fancy or pretty. The jack is an option but as described use caution.
Hi everybody, I am here again with the challenges of a new day. I tell you that I was able to remove all the shirts without difficulties and now I am preparing to start putting everything together but before I have more doubts: I think that during the disassembly process, a lot of material has fallen through the holes in the block and I have not yet cleaned the exedents from the cylinder head gasket. Is there a recommended liquid or solvent to shower the block in all the cavities? Any recommended procedure? Regarding the shirts, each one brings an oring and I see two perimeter grooves, although I can see that in the shirts just taken out the orig was placed in the groove that is lower (closer to the crankshaft) and I see traces of silicone in the furrow above. In which groove should I put the oring? That for the moment, I think I will return later with more questions, about the assembly procedure of pistons, cylinder head gasket and cylinder head. Cesar
Cleaning should be done with a single edge razor blade. Just scrape the deck clean. Tapped holes for head screws should be tapped out and blown clear of any debris. Coolant passages should be blown clean with compressed air. Be very careful not to allow debris to fall into crank journal oil passages. A good practice is to wrap the journals with rags and tape in place.