Tuesday, 31 May 2005
Engine Alignment:
Proper alignment is extremely important.
With the shaft tube and all fiberglass around it fully cured, proceed with the
engine alignment.
At this point, the engine mounts are loose, not bolted to the girders.
You will move the engine back until the transmission coupling touches the shaft
coupling. Since you have a flexible shaft packing gland, the shaft can move
a little bit up and down and sideways. Block the shaft somewhere in the center
the tube: if it moves vertically 1/2?, block it 1/4? up from the bottom, same
thing for sideways movement. Great precision is not necessary.
Now look at your two couplings: they should touch all around, make good contact
with their full surface.

This is probably not the case and you will have to move your engine to mate
the two couplings perfectly.
You will use the engine mounts to move the engine, first up and down then left
and right.

At that point the couplings should fit into each other: there is a little recess
in one and a shoulder in the other one. They should slide into each other easily.
Put your engine neutral and turn the output coupling by hand.
Once the couplings fit, take a flash light and look for gaps. Unless you are
extremely lucky, there will be a gap on one side.
You must close that gap by turning the engine around its axis.
You can move the engine front up and down or left and right with the adjustable
engine mounts.
Once the gap is small, let's say 1/8?, you can bolt the engine to its girders
but leave the mounts loose for the final adjustment.
That final adjustment is done with feeler gages.
The two couplings are precisely machined.
Fine tune the position of your engine with the mounts, gaps measured between
couplings must be smaller than 3 thousands of 1? in all directions.
Tighten all your mount bolts and free the coupling by pushing it back 1/4?.
The boat will move during the transport and we do not want to bind the shaft.
Alignment must be checked immediately after launching the boat. The hull shape
will slightly change: launch the boat with an open coupling, check alignment
in the water and bolt coupling.
Not all boat yards are aware of that procedure.
A removable drip pan under the engine is convenient. That drip pan can be made
to fit tightly in the keel. Do not install it now: you need access to the inside
of the keel for the optional trim ballast.
Fuel system:
See the plans and notes above. A good fuel filter is a must.
Exhaust and Air:
Diesel engines require more air and larger exhausts than gas engines. The engine
room must have an air intake either through a louver vent under the steps or
through large diameter hoses feeding air from under the gunwale.
Do not skimp on exhaust hose diameter.
To prevent the cooling water to fill the exhaust manifold, you must install
a waterlock at the lowest possible level.
To prevent siphoning, you need a siphon break valve or vent in the water injection
system. We prefer an overboard vent as shown on the plans but the cooling system
diagram shows an anti-siphon valve. At the transom, the exhaust must be fitted
with a gooseneck to prevent seawater from entering the system. All exhaust parts
and hoses are available as a kit from BoatBuilderCentral.com.
Water Cooling System:
The engine is cooled by seawater through a fresh water heat exchanger. The
seawater pick up is fitted with a valve (seacock) and a scoop strainer on the
outside. The water supply goes through an optional sea water filter mounted
on a bulkhead.
Insulation:
The engine room compartment can be insulated for noise and heat.
Plumbing:
Refer to the manufacturers instructions for the installation of a marine head.
There is room for holding tanks between the water tanks or under the seats.
With the engine and other mechanical components installed, we can now proceed
with deck installation. |