At Anchor

At Anchor
Whiskyjack at anchor in Garrison Bay, San Juan Island

Wednesday, April 25, 2012

The Engine Assembly and a Poor Man's SpeedSeal

The engine starting to be assembled.
  A couple of weeks ago, I began the work on the engine.  I removed the alternator  and exhaust manifold along with a plethora of smaller items from the engine and then removed the head (with injectors) and fuel injector pump.  The  head, injectors, and injector pump were taken to Cook Engine, the local Yanmar dealer.  I had them grind the valves, replace the valve stem seals, replace the pre-combustion chamber, rebuild the injectors and injector pump.  This work took some time, as some of the parts had to be brought in from  from Japan.  A note here:  It is absolutely outstanding that Yanmar, would still stock all of the parts of an engine that is over 35 years old and was only made for 2 years.

Almost done!

 The assembly work went off without many problems.  It just took time.  The head gasket was installed and the head torqued down.  The rocker arm assemblies were installed, the valve tappets adjusted, the fuel injector pump was installed and re-connected to the governor, and the cooling lines were hooked up.  One of the most difficult parts of the assembly process is getting the small ball on the fuel pump metering rack into the slot in the control arm from the governor.  This happens inside the governor housing, open to the front, but not visible.  You need to stick your hands inside the governor housing, which has very little room, and try to line up the ball with the slot as you lower the injector pump.  It took me several tries.  Then, after successfully completing the task, I realized  that the pump had to come back out because I had not placed a pencil line on the rack to make a future adjustment.

M4 SHCS and Knob
 This engine was designed as a raw water cooled engine and therefore has an external circulating pump to pump sea water through the engine.  The pump is hidden under the governor housing and is nearly inaccessible.  Changing an impeller with pump installed is a real pain in the keester and pulling the pump is even worse.  To help with this and while the pump was out, I replaced the screws that hold the Rear Cover the with stainless steel M4 socket head cap screws (SHCS) fitted with an Acetal resin knurled socket knob.  The "socket knobs" are available by the "each" at Fastenal for $0.22.  They press onto the SHCS and the two parts are assembled, make it a knurled knob (use the jaws of a vise to assemble).

Pump with Knobs
With these knobs, I can install and remove the fasteners with my fingers, without the use of a wrench or screwdriver.  Now, when I need to inspect or change the impeller, I can do it in a jiffy.  I also use a gasket sealant to hold the gasket onto the the Rear Cover and a thin film of grease on the pump body.  That way, when the Rear Cover comes off there is a good chance that the gasket will stay with the Cover and will not be damaged.  This is a poor man's SpeedSeal without the O-ring.  (SpeedSeal does not make a Cover for my pump.)

After the water pump was installed, I bled the fuel system and fired it up.  This old Yanmar hummed like a Swiss sewing machine!  Well,  not really, but it ran well.  There were a few adjustments to be made, but overall, the engine runs great.  Note:  I did not install the alternator and charging system components, nor did I hook up all the engine monitoring.  The charging system is getting an overhaul and will be completed next weekend along with the engine monitoring and alarm system.

So, if you, dear reader, have been following along, I'll bet that you are curious about whether the rebuild accomplished the goal of increasing the engine RPM at wide open throttle (WOT).  I know I was curious and couldn't wait to engage the prop.  Well, it did not!  All of this for a negligible performance increase?  You've got to be kidding!  .....more to come......


  1. Daniel: Love your blog and your boat! Neat trick with the speed seal, tho I have a question: Why the ss bolts? Seems to me that brass or bronze brass or bronze would avoid possible problems attendant to dissimilar metals? John

    1. John: It's always good to think about electrolysis. In the large view, these pumps have stainless steel shafts and pump cams and do not seem to suffer premature deterioration from electrolysis. In a more narrower view, the socket head cap screws I used were off-the-shelf ones made of 18-8 SS. This stainless is very close to brass (the Cover) in the Galvanic Table, just over 200 millivolts, which is the threshold for for concern. Of a larger concern for me is whether the SS SHCS will suffer from anaerobic corrosion. I'm hoping that the fasteners have formed an adequate oxide layer prior to their installation and that it remains intact.