Has anyone ever experienced a high blow-by issue for this brand and type of equipment? We owned more than 40 Komatsu PC200-8 and all are equipted with Debarker / Harvester head for our logging activity. We operate 24/7/365 in Sumatera island - Indonesia and by the end of last year when our Komatsu were achieving HM 7000, engines start to cause high oil consumption. Almost all of them has same failures with broken piston rings. We then performed a rebuild work for all the 40+ engines, in a very short period of time (2000HM) we can already notice a high carbon built up inside the piston head and valve. To our investigations, this poor combustion process may have been the cause and has damaged the rings. We suspect this PC200-8, Tier-3 low emission engine was just not suitable for forestry application however, we need to get more information from you all.
What heads are you using? Have you fitted the machines with additional cooling systems to cope with the high hydraulic through-flow to the heads?
Thanks for your comments. All our units operate with Komatsu (Valmet) 378E & P heads, all were factory fitted with additional hydraulic coolers fitted. No signs of ring breakage caused by over heating or lack of lubrication.Pistons have high carbon build up between top compression and intermediate ring. None of our other Tier 3 engines have this issue only Komatsu !
Have you tried using a low ash engine oil?
Does not sound like you have problems with fuel quality if your other brand engines are not experiencing problems. Do you often get codes dealing with low fuel pressure (CA559)? Tier 3 common rail engines have been durable from my experience. Strange to see large carbon build ups with high pressure injection (up to 15000 psi) which atomizes fuel very well. Fuel filters are very fine, 3 micron on main filter, so use good filters. If injectors get worn from dirty fuel, injector return rate will increase to point that high pressure pump cannot keep up and you will get low common rail pressure faults.
Do you know the specification of the diesel that you have been using and if it has changed? Low sulphur diesel can result in carbon build up and sub optimal injector performance. The engines may have been developed to run on a ultra low sulphur diesel. Have you already talked to your diesel supplier's technical people and the engine oil technical people? I use this http://www.moreyoil.co.nz/moreys-diesel-smoke-killer/ (their website says they have an agent in Indonesia) as a cheap diesel treatment, I understand it was developed over about 10 years to the product available today. You are likely to require a better diesel treatment/ engine oil and there is a myriad of diesel treatments available. I understand one of the Australian products is quite good and probably used in the tropical parts of Australia. For engine oil I have used a semi synthetic with the 'power up' engine oil additives.
How much do you know about the excavators engine control unit and the 'map' that is being used? There have been vehicles from Japan that have been sent to NZ with an engine map for Japanese diesel that did not work so well on NZ diesel. A change of engine map was necessary.
Thank you to all for your comments. In our mixed fleet of close to 1000 units, only the Komatsu have given us premature ring failures, all maintenace systems, oils, fuel is common for all our fleet. For example our John Deere Feeler Bunchers and Skidders, which are Tier 3 No issues. Volvo transport fleet of FH 16 & FM 440 again no issues. When we disassembled these engines only the rings are a problem. The engines I believe are of Komatsu design manufactured by Cummins in China, there are Chinese stampings internally in the engines. When I spoke to our sister company in Brazil they have no issues with Komatsu so I suspect our engines are for the domestic asian market who source piston rings from different world wide suppliers. So if you are in North or South America no issue. Be aware!
I saw a few of the Dash 6 gray market machines in the states with those engines that had ring problems. I would have thought that those issues were taken care of by the Dash 8 line. Are these the 6B5.9 line of motor?
On those dash 6 models do you know if they were also a Cummins engine or genuine Komatsu ?
They were the Cummins engines.
Latest and final update: Komatsu have recognized that in our application, the Piston Ring hardness was quetionable, allowing the abbrasive component of the combustion process Carbon to wear the ring to such a point that it broke and failed. The solution is that Komatsu now have released a PVD coated Piston Ring. Engine overhauls are now in progress using the new Piston Rings.
Let us know how the pvd coated piston rings go.