Home
Next Page
Seafrost
Yanmar PTO Spec
Aqualine
Accessory Mount
As mentioned earlier, custom mounts were needed to accommodate a decent sized alternator. I removed the refrigeration compressor
and alternator from my old engine and reused them on the new engine. My original plans were to replace both with new, but my
budget was stretched. There is really nothing wrong with either accessory. The alternator is an industrial unit that is used on some
trucks and at least one locomotive engine. It puts out 160A at rated engine speed. It is designed to put out full rated power indefinitely.
When coupled with the Aqualine regulator, it keeps up with our power demands by running about an hour each day. Similar alternators
can be purchased for around $250. The regulator costs about the same.

Balmar makes alternators with capacities similar to this alternator. These units with a smart regulator run close to two grand. I'm not
sure what you get for the extra $1500. I think the Balmar units are brushless sealed units, whereas my unit is not. To my knowledge,
there is no requirement for a sealed alternator on a diesel engine. Aqualine lists a regulator/alternator package for this engine for about
$500. It is smaller than the industrial unit I installed and replaces the stock alternator. If someone wanted a good charging system but
wanted to avoid the complexity and cost of a common bed, this might be a cost effective alternative (link below).

The refrigeration compressor is a York type piston pump unit that is relatively new. A newer rotary compressor would run smoother
than the old piston design. This has served well to date.

An aftermarket two-grove pulley was purchased from Sea-Frost. This bolts to the front of the engine PTO. Sea Frost was very helpful
and patient with my questions. I recommend them highly.

A second alternator in combination with a refrigeration compressor can't be mounted to the side of the engine where one would
expect. There isn't enough room. Instead, a mounting platform must be fabricated for the front of the engine, in front of the PTO. The
accessories are mounted backwards onto this platform. This is apparently the case regardless of engine selection. The typical method
used to attach the platform to the engine is to bolt steel plates to the inside of the front engine mounts. These plates extend forward
on each side of the balancer plate. This is the design I used for attaching the accessory mounting platform.

My research indicated that a common problem with custom mounts such as this is a failure to make them strong enough. I used ¼"
thick steel 'L' shaped angle iron. I conveniently had two eight foot long pieces left over from another project. This proved to be more
than up to the task. I purchased a 14" metal chop-saw. This looks similar to a miter-saw, but takes a large cutoff wheel instead of a
circular blade. It makes clean cuts through steel plate like a hot knife through butter. It has some limitations regarding the type of cuts
it can make. I had to get creative to make cuts longer than about six inches. The plates are notched-out to allow sufficient room to
insert a replacement belt for the water-pump and alternator. They extend upward a few inches above the accessory pulleys and flare
out to provide a mounting surface. In cross-section, each sidepiece is 'C' shaped. Since they bolt inside the forward engine mounts,
this increases the distance between the mounts by ½ inch. It also moves the bracket under the fuel pump outboard by ¼ inch. I
dragged the mounting hole to the fuel pump using a saw drill bit. A flat horizontal steel plate is bolted to the top of these side plates
to which the accessories are bolted. Attachment points were welded to the top of this plate for the alternator. The refrigeration
compressor attaches with angle brackets that are bolted into position. The brackets are threaded where bolts attach to make
assembly easier. Otherwise, I'd have to hold a nut under the bracket assembly when attaching the plate; not something that I would
look forward to doing. A single pair of ½" belts will drive both the alternator and compressor. Accessories were positioned so that the
accessory belt length is the same as the main engine belt. This means that I don't have to carry two different types of spares.

Yanmar provides specifications for side loads that may be applied to the PTO at the link at the bottom of the page. Their specs indicate
that the 4JH3-TE should not be used with more than one belt, but my local distributor indicated that it is safe to use twin belts in this
installation. Be sure that you have agreement from your distributor regarding belt loading on your installation before you void your
warranty.
Note: So how do you determine if your alternator is the right size? My
alternator is rated at 160A at 5000 RPM. It is designed to run at a high charge
rate for long periods of time without overheating. My batteries can't accept
a full charge rate for more than a few minutes. After that, the charge rate
drops off. One would think that the alternator is bigger than I need, but this
isn't the case. I normally don't run the engine at high speed when charging
the batteries. Most of the time, I run the engine at about 1000 RPM when on
anchor or my mooring. At this reduced speed, the alternator puts out much
less power. If the voltmeter comes up to the full 14.4V high charge rate
setting about half way through the charge cycle, the alternator is properly
sized.