Engine
December 2008. Original Volvo Penta MD2B (25 h.p.) with MS reverse gear (reduction ratio 1.91:1)
Here is a picture of the original diesel. We were able to start the engine with a help of the ether spray (the weather was quite cold that day). The former owner claimed that it had been overhauled last year and the transmission had been rebuilt. The wiring harness was waiting for a short circuit and a fire in my opinion.
I am thinking of replacing it with a new Volvo Penta D1-30 with MS15L transmission (reduction ratio 2.63/2.96) or Yanmar 3YM20 with a KM2P-1 transmission (reduction ratio 3.22/3.06 or 2.62/3.06) (fwd/rvs).
March 2009. New Yanmar 3YM30 engine
Niemiec Marine repowered Moowind with the new little 30hp Yanmar. It is shorter than Volvo but fattier. Its port side sits very close to the cockpit wall. I would need to remove an alternator in order to get to a starter, for example.
Prop and shaft
A propeller shaft allignment was a major concern because the original Volvo had the shaft positioned below the engine mounts plane and Yanmar has it above by about an inch or so. Hence, the engine must sit lower on its bed. Redoing the bed liners by cutting the embedded metal rails out of the molded fibreglass, and then trimming the mold and glassing in the new metal plates would have been a major expensive refit. Therefore, the new spiffy tall Yanmar mounts were replaced with not so shinny old style short mounts. The matter was of course, not in their brightness but in a weight distribution and a vibration compensation. The new Yanmar has two 150 kg mounts on one diagonal and two 75 kg mounts on the other diagonal. The old style mounts are designed to support equal weight. I wonder if I will be able to detect an increased vibration level because of that?
I had prepared the old Volvo for removal by disconnecting all wires, hoses and a shaft coupler. Next morning after the shrink-wrap was cut, the engine did not want to go through its hatch. Chris from Niemiec Marine had to also remove an exhaust manifold and an alternator and then tilt the engine almost vertically with a pulley.
Once the engine was out, I cleaned its comparment and painted with two coats of Interlux bilge enamel. Thanks god the weather was warm and dry over this first weekend in March for a paint to set properly. I also repaired the hole in a cockpit floor made for the Edson pedestal that I had discarded to make more room in the cockpit.
From contacting multiple marines, I knew that I couldn't get away with keeping the original shaft and prop. The shaft would be too short for Yanmar and the prop would spin in the wrong direction! Moreover, the prop size and pitch should match the new engine's RPM and the transmission gear's reduction ratio. Niemiec used some software to calculate the the prop and came up with 14R10.
The cutless bearing was worn out and I wanted to have dripless shaft seal instead of a traditional stuffing box. Niemiec suggested to use a mechanical shaft seal known as PSS. The original bearing was cut along its length for easy removal from the stern tube. The new Johnson cutless bearing BALE (1"x1 1/2"x4") made by Duramax Marine was compression installed and secured with two set screws on the stern tube outside the hull. It turned out to be half inch longer than the tube, so the excess was cut out.
From Cadler's book I understand that mechanical seals if fail result in rapid flooding but otherwise are perfect and can tolerate shaft misalignment, shaft defects and require no maintenance besides replacing a rubber compression sleeve every five years or so and a couple of o-rings. They have a niple for optional water lubrication, which is mostly useful on power boats due to high shaft RPM when water can be sucked out of the stern tube during an acceleration.
The new shaft was measured and sent out for cutting and keying. What was a surprise when it came back cut a quarter inch shorter than measured! Now what? Through it away and order another one? It would be an expense for Niemiec Marine, probably. One idea was to use a drive saver that is a strong rubber ring that sits in between an engine and a shaft. No, that didn't work because the drive saver was too sick (1" instead of needed 1/4") What worked for the marine and made me a bit unhappy was cutting out 1/4" of the cutless bearing along with the stern tube.
The engine short mixing elbow was replaced with a tall one. Niemiec did the job, it was part of their repowering project. It connects to a water lift muffler.
Fuel system
I replaced the fuel copper tubing with the fuel hoses and Chris from Niemiec Marine fabricated two new fittings to accept them. He also had to cut two new stainless pipes for the fuel supply and return lines that go inside the tank to replace the original copper ones. Volvo engine did not have the return line but the tank had a line connected to a manual pump for removing water from its bottom. This now became the return line and the pump was discarded. It had been broken anyway.
The fuel filling hose was made of water tubing. The deck fitting was unusual size 1 1/4", likely metric, the same as the other end on the tank. I had to buy the entire hose box, 12 feet, because of non-standard size instead of necessary 8 feet. Nobody wanted to cut it.
Yanmar came with its own water separation filter. I just needed to mount it. I also added the fuel shut-off valve ahead of the filter.
I have also replaced the tank's vent hose that goes to a pushpit's pipe end below the deck. Not sure if this is the right way to do because water can get in.
Cooling and exhaust systems
I plumbed the engine's raw water intake to a new Groco bronze ball valve screwed to a new through-hull with a strainer. Another strainer made by Groco and looking similar to a fuel water separator, is seated in-line and is accessible for a periodic cleaning through a companion way's top removable step.
I installed the vented loop between the engine raw water exit and the exhaust elbow mixer, which goes to a fibreglass water lift muffler that I mounted on a glazed plastic lumber platform behind and above the PSS. From the muffler the same 2" heavy-duty exhaust hose makes a loop and goes to a starboard side through-hull, which also had to be replaced because of its size.
I put the coolant expansion tank in the cockpit locker, next to the raw water vented loop.
Shifter and throttle
The original Volvo engine had its shifter and throttle on the Edson pedestal. Since the pedestal is gone, I had to order a new shifter and a throttle. I decided to go with a single lever one for safety and convenience reasons.
The mechanism is fully adjustable for right/left hand and for push/pull gear/throttle operations. It can also be oriented to accomodate the cable incoming direction: forward or aft. It has a safety switch that prevents starting an engine in gear. The throttle can be disengaged from the gear by pulling out a handle.
August 2010. Niemiec cheated!
It was the second year of cruising in the Caribbean when the exhaust mixing elbow just fell off! It got loose a few months after the Niemiec completed their repowering project. As you know, they installed a riser in between the cylinder block and the mixing elbow. The riser did not have the matching thread, so Niemiec just ground off the threads of the cylinder block and the elbow and insulated the entire assembly with the tape, most likely to hide their cheating. When it got loose, I just put two clamps around the insulation tape but it did not last long. I was in St. Lucia when it completely fell off. Luckilly, I was idling at the anchorage in Rodney Bay and did not flood the engine.
I sent Niemiec Marine two emails and received no response. This tells me that those guys are not interested in keeping good relations with their customer who paid them quite a lot of money.
This is the third fault made by Niemiec Marine that I discovered so far. The other two were the rudder fairing that also fell off a month after the job had been done and the bilge pump and the switch, both got loose because there were no washers used, just the machine crews.
I had to fix it myself with what I could find in Rodney Bay area on St. Lucia. Not much, I should say.
I had to further tune the thread on the exhaust elbow with a file to better match the one on the riser. They have 1/16" difference, by the way. Then I purchased new fibreglass insulating tape and epoxy putty suitable for up to 150° C. This of course may be not enough when the engine is running on high RPM. I also embedded two clamps in the putty, just in case it fails, the elbow will not fall off right away. I tested it on low 1800 rpm and I could still touch the riser with a bare hand. I applied putty in the evening and started the motor next day to heat treat the epoxy. It was supposed to cure to the product that could have withstood even more higher temperature. I hope it will.
As a side note, while searching the internet for a fix to my problem, I found that the exhaust riser did corrode and was supposed to be replaced every four years or so. Well, if my new connection last for another three years, I'd be happy.