Of fuel tanks and engine beds

 After the old Chrysler engines were removed, we had several tasks to do before the new engines could be installed.  The biggest of these had to do with the fuel tanks.  The tanks are stainless steel, which is OK for gasoline but not ideal for diesel.  The issue with stainless is something called "crevice corrosion", which attacks stainless steel when moisture is present but oxygen is not, like at the bottom of a diesel fuel tank.  Since the tanks are relatively new (circa 2001, I think), we decided to modify them to handle diesel rather than build new tanks.  The modifications included adding inspection/access ports, water-collection sumps,  new fuel pick-up tubes, and tubes for removing water from the sumps. 

Compadre's fuel tanks with holes for new access ports.

A sump is needed at the bottom of each tank so that water in the fuel will collect there and not slosh around the bottom of the tank (and cause the dreaded crevice corrosion). After cutting an appropriately sized hole in the bottom of each tank, Arren took a large stainless steel pipe cap, removed the threads from inside, and welded it to the bottom of the tank, thus creating a sump.  Very ingenious. 

New sump at the bottom of tank.

New sump viewed through access-port opening.

New fuel pick-up tubes were needed because the old tubes went right down to the bottom of the tank -- great for sucking up sludge at the tank bottom but not so good for engine fuel.  We also needed suction tubes to remove sludge from the new sumps.  Arren decided to place the two tubes next to each other and weld them together near the bottom, thus creating an assembly with good lateral stability (You don't want the pick-up tubes to be wagging around).  This eliminated the need for separate support brackets for the tubes inside the tank.  Again, very ingenious.

New pickup tubes, with tank access-port frame installed.

Fuel pickup tube (right) and sump suction tube (left).  Very cool.

While the tanks were being modified, the engine beds were changed to accept the new engines.  Fortunately the original engines beds were still in fine shape, and they could serve as the foundation for the new beds.  Several wood pieces had been added to the original beds many years ago when the Chrysler engines were installed.  Those old additions were removed and new pieces were added on top of the original beds in order to support the new engines in the proper position. 

We were delighted to find that the frames and floor timbers beneath the engines are still in sound shape and no repairs were needed.  Dirty, but sound.  We could live with dirty! 

Engine beds with new modifications (the unpainted wood).

Next I spent several hours with a paint scraper preparing the engine room for new paint.  Many years of accumulated grime had to go.  And then several more hours with paint brush in hand.  Not a pleasant job, but I have to admit the end results are pretty spiffy.

Newly painted engine room, with port fuel tank in place.

With the space free of engines and tanks, I took the opportunity to re-route a bunch of electrical cables, propane line, etc., that run through the engine room, and placed them in new conduit behind the starboard fuel tank.  I won't bore you with the details here, but this is a big job I had been wanting to do since purchasing Compadre.  It had nothing to do with the re-power job itself, but the three days I spent on it resulted in a more professional installation, and makes future wiring jobs quite a lot easier.

With the prep out of the way, all is ready for the new engines.  We'll have that for you in our next posting.