When I finally got it started after replacing the two fuel pumps (started within 10 seconds of cranking once the fuel lines were primed), I noticed there was oil coming from the exhaust flange between the turbo outlet and muffler (even though I replaced that gasket). The next day when I had more time to run it and put the power to it, I noticed it really smoking out of the exhaust and when I looked at it there was oil spraying everywhere.
When the engine was apart, I checked the impeller on the turbo and it spun freely, so I didn't bother to do anything else with it. Once I saw the oil spraying out of the flange, I figure I have a bad internal seal on the turbo. I pulled the turbo off, the inside of the exhaust manifold was dry, the oil supply line on the bottom of the turbo had oil in it, and the return line on the top was clean so that validated my suspicion. To answer your question Steve, I believe the previous owner ran the oil low from the leak and that caused the bearing to fail and the oil pump shaft to shear. I'm guessing the shaft sheared first and the the bearing failed.
I replaced the turbo and now I have a low oil pressure light on. I put a gauge on the engine and it reads 0 psi. I've verified that the gauge works. I pulled the oil pressure relief valve out and had my neighbor crank it and only get splash oil pressure out of the hole. Also pulled the oil filter and barely anything comes out during cranking.
I pulled the front cover off and removed the idler gear and the oil pump shaft came out with it, no nut on the back end of the shaft. I used to a magnet to get the nut out of the oil pan. The front of the rotor is galled around the front outside edge where it fits against the smaller oil pump gear inside the idler gear. I'm not sure if I have an issue with the o ring on the pick up tube or if I just happened to index the rotor in the block a tad off where the gear mesh between idler and crank is just a little tight and causing the wear.
Evidently the oil pump shaft was spinning with the idler gear and that's what caused the nut to spin loose. I clearly remember tightening this nut inside the block. I also marked oil passages with a paint pen on the front of the block and also on the rotor so during install I could align the oil passages. I did not use the $400 alignment tool to install the pump rotor. Also, I looked at old pictures of when the original rotor was installed before I removed it, and if I put it in wrong, it can't be much. I have pictures of all of these different stages of the teardown and rebuild.
The service mgr at Cat suggested that during the machining when I had the block boiled, maybe the machine shop removed internal plugs where the mfr drills holes to machine the oil passages and water jackets and didn't reinstall them. I'm assuming I'd also have no oil pressure if these plugs were not put back in. These holes would act as pressure relief and therefor not suck any oil from the pan. It never occurred to me to look for these when I put the crankshaft in and verify they were installed. They also never handed me a bag of engine parts that I couldn't quickly identify (old bearings, valves, etc).
I'd love to hear from someone who's familiar with this engine and can shed some light on what's going on.
Thanks.
