INSTALLATION OF A Yanmar 2GM20 DIESEL ENGINE

INTO YANKEE 30 "ANDIAMO"

by Bill Ramelli <wramelli@webtv.net>

I purchased "ANDIAMO" without an engine, put an outboard on the transom and began sailing. After some time I came across a used Yanmar 2GM20 (2 cylinders, 18 horsepower maximum and salt water cooled) that I felt would push the boat adequately. I sat down with my mechanical engineer friend, Paul Whittington to discuss the installation of the engine and he came up with the following. Fit the engine in the existing space so that changes in the engine cover and the cabin sole would not be necessary. (See Fig. 1) Shorten the prop shaft. Install a thrust bearing on the prop shaft. Couple the engine to the prop shaft with two CV joints and a shortened axle.

Yanmar 2GM20

Simple, do that and you have no space problems, no alignment problems and you certainly won't destroy your settee bunk. You will be able to put your hand on the shaft log with the engine running in gear and feel absolutely no movement, something I have not been able to do on many boats I have owned. This sold me. The following is roughly how this type of installation can be done.

1. Build a simple mock-up of the engine that will be the same size as the engine to be installed and that will show all the maximum dimensions. Use a piece of 1/2 inch plywood for the plane through the engine that the engine mount hangers are located on and attach pieces to this. (See Fig. 2)
2. Place this mock-up in the allotted engine space and mark the starboard motor mount base, which is bolted to the hull, so that it will allow the engine to sit in the location you want. Remove the mockup-up and the motor mount base. Cut the base and tack weld flanges on the base to accept motor mounts. Bolt the motor mount base back in the boat and make sure you have a proper fit. This may take several tries. When you get the proper fit unbolt it and weld the flanges on solid. Now bolt it back in the boat.
3. Purchase a 1/4 inch by 2 inch by 20 inch stainless steel strap and bore and tap 4 holes in it to accept the motor mount bolts. These must be dimensioned so that the engine will fit on the mounts after they are bolted on.
4. Using some threaded rods (see Fig. 3), attach the bored and tapped stainless strap to the threaded rods. The mock-up height can be changed by adjusting the nuts under the mock-up and the stainless steel strap height can be changed by screwing the threaded rods up or down in the strap.
5. Clamp the engine mock-up in the desired position. (see Fig. 4) Mark the area that must be removed to allow placement of the stainless steel strap. With a hammer and wood chisel remove the old wood motor mount base and the glass around it so that you will have plenty of room to glass the strap in place. Now adjust the threaded rods to the ss strap so is located where you want it. For greater stability it is probably better to get it down pretty low, maybe an inch off the hull and to use a spacer between it and the motor mounts.
6. Mix up some resin, glass fibers, and micro-ballons into a dough consistency
7. Make a dam around the inboard side of the ss strap.
8. Force the doughy glass mixture under the ss strap and smooth the mixture out so that there are nice fillets on the edges of the strap because this has to be fiber-glassed into place. Make sure to wrap the rods that extend below the strap with some kind of material that will allow the rods to be extracted. These rods should extend below the strap and contact the hull.
9. After the resin mixture hardens, remove the engine mock-up. (see Fig 5)
10. Apply a mass of mat and roving over the strap and out 6 inches and resin this in place. Use a liberal amount of glass for this application.
11. Bore holes in the oak spacer for the motor mount bolts to pass through. Bolt the motor mounts on the ss strap with the oak spacer in between. Don't use bolts that will come in contact with the hull.
12. Strip the engine so that it is light enough for you to muscle it around in the boat. Taking the transmission, flywheel, alternator and starter off will lighten the engine considerably.
13. Place motor on motor mounts. (see Fig. 6)
14. Bolt engine accessories back on engine and check to see that there is sufficient clearance for the motor enclosure and cabin sole to fit. (see Fig. 7)

THAT TEMPORARILY FINISHES WORK ON THE ENGINE SO WE MOVE TO THE PROP SHAFT. TIME FOR ANOTHER MOCK-UP, THIS TIME FOR THE THRUST BEARING PLATE AND THE BEARING PLATE HOLDERS.
	Fig. 8. View of thrust bearing assembly showing the following: Thrust bearing and thrust bearing assembly Thrust bearing plate Thrust bearing plate holders (glassed in). Prop shaft flange

15. Construct a thrust bearing plate out of 3/8 inch steel plate that will fit in the bilge area and cut a hole in it that will allow the shaft to pass through.
16. Construction of the thrust plate holders. Using the mock-up to help with dimensioning, cut steel straps and bend them to fit the curvature of the hull where they will be glassed in. Tack weld some ears on the straps, these are to be used to bolt the thrust plate to. Clamp the parts together after they have been nicely fitted, remove them from the boat and weld the ears securely to the straps.
17. Now place this whole assembly back into the boat and adjust it so that the prop shaft goes through the center of the hole and the straps fit nicely to the hull and clamp the whole assembly together. Bolt this together and stick it in the boat with some glass resin mixture.
18. Remove the thrust bearing plate and securely glass the two straps in place in the same manner used to glass in the ss motor mount strap.
19. Slide the thrust bearing on the shaft and bolt on the thrust bearing plate. Position the shaft in the center of the shaft log for alignment purposes and clamp the thrust bearing to the thrust bearing plate. Now take the plate/thrust bearing assembly out of the boat and bore the necessary holes to bolt them together.
20. Bolt the thrust bearing and thrust bearing plate in place.
21. Turn a prop shaft end flange on the lathe. (see Fig. 9)
22. Position the prop by sliding the prop shaft in or out of the boat and mark the shaft so that the end flange will fit about an inch ahead of the thrust bearing plate. Cut the shaft to size and cut a 1/4 inch keyway on the shortened shaft.
23. Measure the distance between the engine flange and the prop shaft flange and cut an axle/CV joint assembly (in my case a 1984 VW Transporter) to size. Place a spacer between the engine flange and the forward CV joint because the nut extends past the engine flange. The engine flange, the spacer and the prop shaft flange must all be bored to the same bolt pattern as the CV joints.
24. Bold the CV assembly in place.
25. Make a water lift muffler to fit under the engine. (see Fig 10)
26. Lift engine out, place muffler in bilge under engine and replace engine. (see Fig. 11)
27. Build an exhaust pipe to fit in the same area as the atomic four pipe. Use 11/2 inch stock copper pipe and fittings and braze the assembly together. Take the exhaust high and then down to exit out the old exhaust that goes to the stern.
28. Connect engine exhaust to lift muffler and lift muffler to the exhaust pipe going into the head region. (see Fig 12)
29. Hook the hot engine water that goes into the head region to the anti siphon valve located one foot above the water line. Hook the return hose to the other side of the anti siphon valve and connect the other end of this to the exhaust manifold.
30. Make a new fuel tank and install it. Install a shut off valve and filter/water trap next to the tank. Vent the tank and bring one fuel line forward to the engine compartment and take another line from the injectors back to the tank. (see Fig 13)
31. Hook up engine controls.
32. Hook up the electrical. This may be a good time to go through the whole electrical system. Install new gauges as well as alarms.

I've probably omitted several things, but I believe I have covered enough to be helpful to someone installing an engine. I give a lot of credit to Paul Whittington for the engineering as well as overall help and to Rod Holland for the complicated machining work which I didn't have machinery to do.

It has been fun, but it sure is good to start the motor and take off without hanging over the transom to tend to a 6 horsepower outboard.

Good motoring

Bill Ramelli