Rebuilt Cummins Fuel Injection Pump

I picked up Nellie's rebuilt fuel injection pump at J.G. Parks yesterday.  I though there was a mistake as it looked brand new.  They even replaced the metal placard with the engraved part number and serial number.  The cost was $854, $200 more than I paid in 2014 at Nozzle Masters in Orlando, but J.G. Parks replaced about $300 worth of parts, including the main drive shaft.

I got the four fuel injectors back yesterday too.  They were in a million pieces!  I'd asked them to quote a rebuild but balked at the $400 estimate.  The tech told me yesterday that to provide an accurate estimate they tore the injectors apart.  When I passed on their price, they passed on putting them back together.  I guess that's fair but not what I'd envisioned.  The good news is I've already purchased 5 rebuilt injectors at a total cost of $140.  Looking on the bright side, after seeing the injectors apart I now know how they work.

Finding the Engine Overtemp Problem

Engine Gauge Display after Engine Warmup

Removed some paint between the engine block and it's ground wire.  Then applied aluminum antisieze to all the surfaces.  The water temperature gauge now reads  (sort of) correctly 190°F vs. 180°F.

Fuel Injector Leak

Looking Up from Underneath the Fuel Injection Pump

Nellie has been leaking a little fuel (enough to wet-out a napkin in a 50 mile run) somewhere near the injection pump's distribution lines.

A small drop of fuel can be seen hanging from the injector tube support bracket.  The likely culprit is a loose connection or bad washer between the injection tube and the pump.

Cummins 4BT Water Pump

Telltale of a Leaking Water Pump 

During the morning engine check I found that the water pump's shaft seal had started leaking.

I replaced the pump with a used spare we had on board. A few days later I purchased a new one at NAPA for $54.

Trying to find a water pump for your 4BT3.9M? At an autopart's store tell them you've got a 1991 Dodge D250 w/ 5.9 Cummins turbo.

The Cummins parts catalog for the 4BT3.9 lists the following for water pumps: 3802004 and 3913432.

3802004 crosses to a NWP 557145 in NAPA numbers.

3913432 crosses to a TFP 41181 in NAPA numbers.

Conductive Grease

Years ago a friend at the Long Beach Naval Station gave me some conductive grease.  He said it was commonly used to both seal out salt air and improve the conductivity of electrical contacts.  I've been looking for the stuff ever since.  

Today, while putting (aluminum based) antisieze on the raw water pump's bolts it dawned on me that this is what the Navy electricians were using.  I put an Ohm meter across some of the stuff and sure enough, it's conductive.

A Closer Look at the Rudder Post Cutless Bearing

I've been wondering why there's a cutless bearing, or what at first glance appears to be a cutless bearing, in the rudder post.  Perhaps the yard's purpose wasn't additional support, but rather to aid in the installation of the rudder post tube.  Specifically, they wanted to keep the post centered, within the post tube, while the post tube was being fiberglassed into the hull.  Here's a picture of an installed post tube.  It's 7" long (1" of that protrudes outside the hull), with a 2" ID and 2-1/2" OD).  

The Fiberglass Post Tube Penetrates the Hull and is Fiberglassed Into it.  A 7-1/2" x 2-1/2" Hose (Not Shown) Connects the Post Tube to the Packing Gland.   The Metal Retainer, Seen above the Post Tube, Keeps the Lower Part of the Packing Gland From Moving When the Upper Part of the Gland is being Tightened.

I imagine the yard installed the rudder posts something like this.  Drill a hole in the shoe and install the gudgeon.

The Shoe's Gudgeon (or Lower Rudder Post Bearing)

Next, mount the rudder post's upper bearing in the lazarette.  

The Upper Rudder Post Bearing

Next, drill a 2" hole through the hull on a line between the upper and lower bearings.  

Next, slide a 1-3/4" rudder post through the upper bearing and then through the hole in the hull.  Before seating the post into the gudgeon, slide the post tube onto the post.  Push the post tube against the hull and draw a line on the hull at the intersection of the post tube and hull.

Remove the rudder post and cut along the line on the hull.  Now, finally, install the rudder post and post tube again.  Slide all but 1" of the rudder tube into the hull and fiberglass it into to the hull.  And there you have it, a perfectly aligned rudder post and rudder post tube.

A Piece of Rubber Emerging from the Rudder Tube

In conclusion:  The rubber that we've seen coming out of the post tube for years isn't part of a cutless bearing.  The rubber was there to make sure that there was a tight fit between the rudder post and the rudder tube during construction.  Once the fiberglass had set the rubber was superfluous.

Rethinking the Intermediate Bearing's Barbed Fitting

Here's what Nellie's fitting looked like after it was removed for inspection.

Nellie's Barbed Intermediate Bearing Fitting

They say a picture is worth a thousand words.  Well, here's a picture.

Nellie's Barbed Intermediate Bearing Fitting

The fitting crumbled yesterday during reinstallation.  Mike McCoy, Tug E. Bear 37VT62, warned that these fittings might be brittle.  How right he is.  

For the record, the fitting is 3/4" NPT and 3/4" barbed.

It was replaced with a poly fitting of the same dimensions.