Engine Room Prep

We had some other things going on concurrently as well.  With the engines removed we had some clean-up to do.  I expected quite a heavy coating of grime and grease on the bottom below the engines, but it was surprisingly thin for a 40 year accumulation.  Most of it came off with a plastic scraper, followed by some wire brushing and cleaning up with some spray on detergent.  The bottom then got a couple coats of gray paint to give it a more tidy look.

I also extracted samples of the ATF in each transmission and sent them off to a lab for analysis.  Our transmissions are Borg Warner model 73C Velvet Drives.  The model 73 is no longer made, as the model 72 was proven to be quite a bit stronger than specified and the 73, a little stronger (and more expensive) yet, never really caught on.  Conventional wisdom calls for replacing or rebuilding transmissions while they are more accessible with the engines out - but we have not been known for embracing conventionality with our project.   These transmissions are not inexpensive to rebuild - around $3000 each, plus whatever it would cost to do the reduction gearbox behind each one.  The lab analysis came back with no red flags, the transmissions have performed well in the past and we decided to risk leaving them in place and follow the advice from the lab, which was to change the fluids and check it again in a year or two.  The ratios of various elements to each other were pretty much in line as they should be, and some higher parts per million of some elements were attributed to the length of time the fluid had been in there without being changed.  They did get a coat of fresh gray paint - we couldn't have them Perkins blue once connected to their new power source.

 

Although the engines were out, we still had remnants to remove.  The wiring bundles still ran from the engine room back through the bulkhead, then up through the back of the guest cabin closet to the helm up on the bridge.  Snaking these bundles out took some time, as they were secured to ribs and bulkheads every couple of feet or so.  We did one side at a time, first pulling the wires detached from the Perkins instruments down through the closet, laying them out in the aisleway.  The port side wires were pretty much a direct shot through the bulkhead into the engine room as the closet is on that side, but the starboard wires took an extra turn going under the floor of the aisle, and another 90 degree turn into the engine room.  We tried to maintain some integrity of the wires, and had labeled them with masking tape before we disconnected them from the various engine sensors.  If we did indeed sell the old engines, the wires and gauges would go along with them.

Our batteries are configured with house batteries on the port side of the boat and engine start batteries on the starboard side.  With the Perkins, both engines used the same battery bank for starting, with heavy battery cables going to each engine.  That will remain the same with our new engine setup, but the Perkins engines were 24 volt systems, while the new engines will be 12 volts.  The starting batteries were 2 8D batteries connected in series to make 24 volts.  I changed the cables connecting them to a parallel connection for 12 volts.  It provides more amperage than we'll need for that purpose, but the batteries were there and still in fine shape.  When it's time for a change we may go with a couple of group 31s instead of new 8Ds.

I had installed a high amp alternator on the port Perkins with a 3 stage regulator for charging our house batteries.  I put the stock alternator back on that engine and kept the newer alternator, but I don't think it'll fit on the Cummins.  If not, it'll become a Craigslist sale item, which is where I found it in the first place a few years ago.  We'll keep the same charging structure of port charging the house batteries and starboard charging the engine batteries, but we may add a battery combiner device that will permit cross charging the house batteries from both engines.  That wasn't an option before with the starboard engine running a 24 volt alternator, but now the engines and the house battery system will be on the same page - er, voltage.

Abaft of the starboard engine is an air compressor and two air tanks.  The tanks supply the air for operating the set of four Buell air horns that are mounted on the roof of the salon, and there is also an outlet that can be used for auxiliary purposes.  For quite some time this air system has had some leaks and couldn't hold its pressure for more than a few minutes.  Because we needed about 5 minutes of compressor time to charge the tanks, we could only use the air horns for 'planned events', such as passage through a narrow, one-way channel, or maybe a celebratory honk after the flag ceremony at Roche Harbor.  Access to it was extremely limited with the Perkins engine in place, as the turbocharger hung out over the transmission and the exhaust hose crossed over in front of the compressor.  The compressor is green and the tanks yellow, as seen in this photo.  The two tanks were connected by a copper tube, and each tank had a petcock on the bottom for draining water accumulation.  The air line from the compressor was also copper, and supplied the outboard tank.  All the copper tube connections used compression fittings, and they were all seeping air, as evidenced by bubbles when we applied a soapy solution.  The petcocks at the bottom of each tank also were a source of air leaks.  We removed them, finding only a drop of water in the tank supplied by the compressor, and none in the second tank, which got its air from the crossover pipe.  We replaced the petcocks with plugs.  We also replaced the lines from the compressor to the tank and the crossover pipe with plastic tubing and new compression fittings.  The tanks held the air quite a bit longer, but there was still a mystery leak.  We added a check valve between the compressor and the tank, and voila!  The tanks now held air for at least two weeks before the pressure dropped enough for it to turn back on.  Now I can just leave the compressor turned on all the time, as it seldom cycles unless there's some usage of air.  I had purchased a 12 volt air compressor some time ago to add to the system, but I don't think I'll need it.  Our inverter is capable of supplying the 110 volt power to the compressor while we're away from shore power.  It draws about 70 amps, but it only runs for 5 minutes or less.  Erin is so pleased now that we can blast those horns anytime we want!

Oil changes have always been a bit problematic on boats, as you usually can't just put a drain pan beneath the engine and open the plug.  On the Free Spirit, I had a small electric pump with alligator clips to connect to the battery.  I would snake a small plastic tube down the dip stick tube and pump out the oil into a container.  It was slow going and usually messy.  On the Potentate each Perkins engine was equipped with a hand pump that tapped into the bottom of the oil pan.  I could clamp a somewhat larger tube to the pump, run it over to a somewhat larger container and hand pump out the 3 gallons of oil from each crankcase, all while kneeling in an awkward position.  The Cummins engines will each be equipped with an oil hose connected to where the drain plug would normally be.  There are a few products on the market expressly for changing oil on engines so equipped, and I found a good deal on one, on Ebay.  It's called an Oil XchangeR.  It consists of a reversible pump and a 3-way valve for directing oil.  It can be connected to three engines - our two mains and the generator.  There's another terminal with a hose, and this is for the oil container.  So, I'll be able to select which engine I want to work on, then flip a switch to pump the oil from the bottom of the pan into my container.  I can then put the hose into the container of new oil, reverse the pump, and refill the engine with the new oil, pumping it straight into the oil pan.  To do the next engine, change the valve to that connection and repeat the process.  This unit isn't installed yet, but it will be before the season is over so we can do our first oil change.