gromitbeast
New member
Hey Guys,
Happy to be a new member of what appears to be a great forum. I have recently acquired a JM-254 circa 2001 with a Y385 engine. I appear to be getting some blowby characterized by loss of power under load and smoke coming out of the crankcase breather. Tractor does start and run. The tube connected to oil fill on the valve cover is sucking and free from obstruction. From my research on this forum and CTOF it appears that my most likely candidates for this are stuck/bad rings on one or more of the pistons or a crack in the block. Before tearing everything apart I'd like to test compression. I suspect that pulling the glow plugs and testing compression there is my best bet. Can anyone help me with the following questions:
1. Am I missing any obvious or easy troubleshooting steps here?
2. Are there any best practices or known procedures out there for running a compression or leakdown test on these. Anyone know what the glow plug threading is?
3. What sort of pressure should I see? Specification on Y385 is 22:1 so I'd expect 22 atm or 323 psi or more right? Anyone have practical experience on this value?
4. As long as I'm pulling the glow plugs for compression testing I plan to replace them and the sealing rings? Manual says model 1055 Part No. Y480G-12200 it also calls it the "A Shrouded Electrothermic or Preheat plug 10-12-65, 12V" I'd sure like to cross these to a locally supplied champion, ngk or autolite part number anybody have some advice on how to do that? I've tried calling napa, autozone, etc with no success
Thanks for your help!
Nick M
Illinois
Happy to be a new member of what appears to be a great forum. I have recently acquired a JM-254 circa 2001 with a Y385 engine. I appear to be getting some blowby characterized by loss of power under load and smoke coming out of the crankcase breather. Tractor does start and run. The tube connected to oil fill on the valve cover is sucking and free from obstruction. From my research on this forum and CTOF it appears that my most likely candidates for this are stuck/bad rings on one or more of the pistons or a crack in the block. Before tearing everything apart I'd like to test compression. I suspect that pulling the glow plugs and testing compression there is my best bet. Can anyone help me with the following questions:
1. Am I missing any obvious or easy troubleshooting steps here?
2. Are there any best practices or known procedures out there for running a compression or leakdown test on these. Anyone know what the glow plug threading is?
3. What sort of pressure should I see? Specification on Y385 is 22:1 so I'd expect 22 atm or 323 psi or more right? Anyone have practical experience on this value?
4. As long as I'm pulling the glow plugs for compression testing I plan to replace them and the sealing rings? Manual says model 1055 Part No. Y480G-12200 it also calls it the "A Shrouded Electrothermic or Preheat plug 10-12-65, 12V" I'd sure like to cross these to a locally supplied champion, ngk or autolite part number anybody have some advice on how to do that? I've tried calling napa, autozone, etc with no success
Thanks for your help!
Nick M
Illinois