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Hyperion's new engine
Hyperion, a C&C 27 Mk I, received an upgrade from her original Atomic 4 to a Yanmar 2GM20 after the original engine failed in "uncomfortable circumstances". Fitting this engine, says owner Ralph Ainslie, demands a minimum of work, and the only task beyond the average owner was the creation of a new S/S exhaust, which Ralph says could be done at reasonable cost by any welding shop. Complete comments below.
The bottom three pictures show a similar installation on Towser, a Mk IV whose A4 failed. The engine here is a Yanmar 2YM15 – slightly less powerful than the 2GM20, but still more than adequate to moving a 27. The 2YM15 fits well into the A4's space, and is easy to service despite having its oil filter and dipstick on the starboard side. Noise was a surprise; the 2YM15 is supposed to be relatively quiet, but compared to an A4, makes an unbelievable clatter. The addition of foam noise insulation brought sound levels down to a reasonable level.
"This winter, I replaced Hyperion's engine with a new Yanmar 2GM20 2-cylinder, 18HP diesel. The reason for the replacement is that the original Atomic Four had failed on me twice in uncomfortable circumstances.
Thoughts on costs
Recently (Feb. 2008), a BC owner was quoted $7500 for a Yanmar and $5000 for the installation (at a $70/hr rate), which he found discouraging. However, while it might cost several thousand dollars of a mechanic's time to do the job, installation doesn't need to be done by a mechanic. Rather than abandon the thought of a new engine, it was suggested, he should do the work himself, as Ralph Ainslie did. There is nothing in an engine change that anyone who is reasonably competent with tools cannot do. My perception after watching some of the work being done on my boat and doing some of it myself (and saving quite a bit thereby), is that if you can confidently look after an engine (change oil and filters, winterize, etc.), you can swap one of these engines into the boat with the help of a friend.
There is one complication – the competing needs of getting the old engine out and the new one in, which is easily done with a club mast jack or even the boat's own boom and a block-&-tackle (in other words, on the water), versus the need to have the boat out of the water to replace the shaft (not obligatory but desirable, as you'll probably find the old one is quite worn and a new shaft can be a bit longer, allowing you to position the engine slightly farther forward); it's nice to replace the cutless bearing too. Also, you will have to resize the exhaust fitting on the transom. These competing needs could be dealt with through a bit of planning or – something sailors are good at – improvisation.
You can remove an A4 more easily by removing the wood cross-piece that supports the front of the engine cover. You will have much more room to work. Also, you can lift the engine straight out with a crane. You will need a #1 or #2 Robertson head screwdriver ( a variation is apparently sold in the US by Home Depot as a "square drive" screwdriver). There are three or four screws a side and then the cross-piece just lifts out. The engine is gearcase-heavy and will bind on the mounting bolts if you just try to lift it with the lifting eye on top of the block. Instead, drop a strop three or four feet from the lifting hook to the hoisting eye. Then, from the same hook, drop a block and tackle and make it fast at the rear of the gearcase; the block and tackle should make a slight dog-leg as it passes under the cockpit. With everything disconnected on the engine, tighten the block and tackle until the aft end of the engine rises. It's okay if it binds a little bit on the mounting bolts, but not too much. Raise the hook a bit until the front end of the engine binds a bit. Repeat until the engine is off the mounts and hanging free.
The Yanmar 2GM and 2YM engines are virtually a drop-in replacement. You don't touch the glass (see Ralph's comment above). The steel angles on top of the fibreglass or wood beds need to be changed, but anyone who can use a measuring tape and hold a hacksaw and a drill can do that.
If you have a steel tank you must replace it (see Ralph's comment above – original steel tanks are way past their best-by dates and so are some aluminum ones). If you have an aluminum tank, you're not off the hook; these can develop pinholes thanks to corrosion from within or, more commonly, from prolonged contact with wetness from the base on which they are mounted. You should lever it up and inspect the underside for corrosion before you start the engine replacement process, because the easiest time to get a tank out is through the engine bay. A replacement plastic tank will cost between $100 and $200.
Cleaning a tank is sometimes made out to be a big deal, but all you have to do is take the fuel sender off the top and you've got a hole large enough to insert a pump hose into the tank and, when the tank has been drained, to insert a dowel wrapped in paper towel – this will blot up any bits of crud on the tank bottom. You don't have to get every bit of the gas out. A diesel will easily tolerate a concentration of gas as high as a litre in the 50-litre tanks on a 27.