Posted by Dan (NH) [108.162.219.144] on Wednesday, March 23, 2016 at 08:51:51 :
It is a T207 out of a 1941 WC4. I wasn't expecting to have a super clean engine that didn't need to be rebuilt, but what I found made me wonder. If these trucks could talk, just imagine not only the stories of their travels, but about the individuals that operated and worked on them through the years.
Last night was a slow moving, take it apart at my own pace approach to tearing down my straight 6. As long as I don't rush, I can usually find all the pieces and parts when I go to reassemble. Like everybody here has done at least once in their travels, I was hoping to look into the cylinders and see a beautiful cross hatch still present on the cylinder walls, but that was a long shot for an old truck like this. It did run smooth before I tore into the truck, smoked a little on startup, but that would go away after it warmed up. There was no extreme clunking or wrapping, that is why I was optimistic.
First, after getting it rigged up in the engine stand, I pulled the oil pan. Everyone should know that you NEVER flip an old engine upside down with the oil pan still on. The 2 inches of gooey sludge at the bottom of the pan is reason enough not to go inverted. I say this now, but I knew from past experience from other engines, it will make a mess inside the block.
I did take all the accessories off the engine, including the manifold. Very happy after I removed the water pump, to find the water diffusion tube was almost brand new looking and came out with two fingers! That never happens! The only thing that remains on the engine now at this point was the head and timing cover and the stuff under them. Helps if I keep the weight down for that Chinese knock off engine stand I have. Not a whole lot of faith in that stand, but it hasn't let me down yet, and I figure there have been about 7-8 engines rebuilt in it.
Carefully I spun the engine over in the stand so it was upside down. I got the usual coolant leaking from the thermostat hole in the head, so that was 5 minutes of cleanup. Once upside down, I took a quick look and it was very apparent something was missing. There was no oil pump pickup float attached to the oil pump pickup pipe. Gone, but not forgotten. I dug around in that two inches of sludge at the bottom of the oil pan and pulled out what was the pickup float at one time. It looked like it had been in a brutal fight with the connecting rod ends an the crankshaft for quite a while before finally being pierced and sinking to the bottom of the pan to hide from the wrath of the rotating assembly. I will have to get a photo up, it looks like it was hit a gazzilion times. That's right, a gazzilion times! Public education at its best.
Looking at the cotter pin in the aluminum retainer "which was still present" it was clear that who ever rebuilt the engine used a size too small, which let the pickup slide right off. I also found stampings on the crankshaft "M10?10" which makes me suspect the crank was ground once before too. Tonight I will pull the head and see if the piston tops are marked. The cylinders look OK, but there is definite wear on the thrust sides. It will need boring, which is alright, I am in it for the long haul.
It was a good choice pulling it down, as I questioned if it needed it because it ran well. The bearings are smoked on the rod ends, so I will need to have the crank ground.
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