| [GMCnet] update on the incontinent diesel engine [message #174658] |
Tue, 26 June 2012 16:18  |
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Marc Hogenboom[2]
Messages: 70
Registered: March 2011
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Here is an update on the status of my incontinent Diesel engine.
After making it home from Shawnee with the help of Hal Kading and Carl Stouffer I left the coach alone for a while. I had been under it a little more than I liked.
After a couple of weeks I started by doing a compression test on all cylinders, a job that requires taking of the turbo and the d.s. exhaust manifold, to be able to crew the adaptor into the glow plug borings.
All cylinders came out about the same, so no real damage there. The turbo bearings however had way to much play, so a rebuild kit was ordered online. It took 10 days to get the parts here and 1 hour to rebuild. After putting everything together I hooked up a pressure/vacuum gauge to the crankcase to find out what was going on. I took the coach for a drive and found that on idle and light load there was a nice small vacuum in the crankcase, but on more than half load the crankcase was pressurized. This explained the oil leaks while driving and no leaks while idling. Besides that there still was way to little boost despite the rebuilt turbo. Now I took out the CDR (crankcase depression regulator) and hooked up the breather line directly to the air intake and drove again. Now there was a nice vacuum on any throttle position.???? Still too little boost! What would cause this? Finally I thought of taking the air intake apart and check the cleaner.
MOUSE NESTS.
Between preparing the coach for the trip to Shawnee and the actual trip a family of mice must have taken up residence in the air cleaner box.
Than too much vacuum on open throttle caused the CDR to close and the pressure in the crankcase to build up. As soon as the engine was at idle again, CDR opened and there was case vacuum again. This is a new one for me! The case pressure must have prevented the free oil return from the turbo, causing the bearings to wear down extremely fast.
After cleaning the air cleaner, crankcase vacuum dropped to just above zero, turbo worked as it should and the leaks are mostly gone. Front mail seal developed a leak as a result of the over pressure, so I’ m not done yet, but the cause has been found. I threw away the CDR and built a catch can instead. Now I can keep an eye on how much oil gets sucked out of the crankcase and I’ll be sure there is a vacuum.I put a mesh over the opening in the air cleaner box, so the mice cant get in.
We took the coach for a 2 week camping trip and all went well, just a few drops from the main seal, so for now all is good again.
Marc Hogenboom
‘73 Painted Desert Diesel
Madrid NM
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