Thursday, December 14, 2023

Rattle Can Rebuild Part 2

With the engine setup in the stand in my shop, I started tearing it down as much as I dared, taking lots of pictures along the way.  I have both the service manual and parts schematic on hand but the photos will really tie it all together once I started building it back up. 

The first order of business aside from photo documentation of all angles of the engine was to assess the condition.  Even though it only has 974 hours, it has been sitting in a garage for many years and there was a fair amount of rust, dirt, and chipped paint on the lower half.  I cleaned up as much as I could with a stiff wire brush and then hit all of the nuts and bolts with a liberal dose of PB Blaster to hopefully loosen up any rust that would prevent their removal.  

Somewhere along the way I decided to split the rebuild into 2 parts, mainly because of my fear of keeping the engine cantelevered on the bell housing in the stand and potentially cracking or deforming the housing (even though I keep the chain hoist tensioned).  The first part would be to get all the lower parts cleaned up, replaced, and painted and then move the engine back into the rolling dolly where it sits on its mounts.  The second part of the rebuild would be to do the same to the top half of the engine.  I'm probably doing it backwards because when I re-do the top half I'll get the bottom dirty again by virtue of gravity, but it is what it is, and I'll try to be careful and neat.

Along the way I found the following issues to address:

  • Fresh water cooling pump - appeared to have been leaking. Replace
  • Raw water pump drive gear - the slot where the water pump mates into is deformed. Replace
  • Front engine mounting bracket -  just all janky with rust. Clean and paint
  • Bottom of engine block - more janky rust. Clean and paint
  • Oil pan - leaky around the seal and want to replace the drain hose. Replace hose, clean and paint
  • Rear main seal - evidence of an oil leak behind the flywheel. Replace

The good news is that I think I have all the parts I need, but I've never dug this deep into a diesel before so I'm sure I'll be learning a lot along the way.  

Anyway, after letting all the bolts soak in PB Blaster for a few days I got started and removed the fresh water cooling pump.  I was able to crack the bolts without issue and had the pump off in a few minutes. However, when I looked into the hole behind the pump (inside the cylinder jacket) I could see a lot of rusty scale and old antifreeze sludge. Not good. I needed to get that all cleaned out before I put the new pump and cooling system back on because I don't want that circulating through the system.  Additionally, the rusty scale on the cylinder jacket probably keeps the engine from efficiently cooling.

I did some research and took a trip to the autoparts store and picked up a gallon of Evaporust. This is a chelating agent that basically bonds to rust and scale and puts it in solution.  I cut a piece of plexiglass, drilled bolt holes in to match the pump pattern and bolted it onto the engine where the pump used to fit.  Then I pulled off the thermostat housing (highest point of the fresh water cooling system in the engine) and poured Evaporust in until it filled up to the top and let it soak.

After two days, I pulled the petcock off the lower end of the engine and drained it all out. The result was pretty amazing (and disgusting).  I couldn't see any more rust and scale and all the sludge had miraculously disappeared.  The almost clear Evaporust solution that I had initially poured in was now a chunky jet black color.  I may have created a hazardous waste problem, but at least the inside of the engine is now clean.  I'll flush it all again once I have it put back together, but I'm pretty happy with the result. 

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