Feb 28, 2008 - Battling Alligators: Rebuilding the Isuzu
by Michel & Jane DeRidder

Big Grunt, Magic Dragon's DA220 75hp Isuzu diesel engine is thirty-seven years old. It has given us 17,000 hours of service. That's a hefty running time for a yacht engine. But then one day we noticed the cooling fresh water needed replenishing. Otherwise all seemed to be well. The crankcase oil didn't show any water in it. Oil pressure, temperature - vital signs were normal. There was no sign of a problem other than the slowly descending water level. So the first guess was that the heat exchanger must have developed a leak. We had a couple of sleepless nights before deciding to return to home pilings in the Kerikeri River to deal with the problem.

First, we emptied the space surrounding the engine compartment. Some items went ashore - the Honda 90 motorcycle, the wooden partitions enclosing the engine space for repainting. But most everything else fit into the stern cabin, although fenders and lines went up on deck leaving our main living area the same as always. And so began a lengthy battle with alligators because by this time, after pumping oil out of the engine we discovered that indeed water was leaking into the engine oil and we had a bigger problem than a leaking heat exchanger.

Michel decided that it was time to take the engine out and do a proper job. After all, twenty-three years had gone by since we last had it out and it was time to clean the engine compartment and repaint it. So he disconnected everything from the engine, cut the seal and unscrewed the cockpit floor. A truck with a hoist was to meet us at the Stone Store wharf at high tide on a certain day. '"We'll need a third person," said I. Instead, we cast off our lines, hanging them on the pilings ready to retrieve. Michel, in the dinghy, towed our bow out into the incoming current until we had steerage, then after tying the dinghy with its 8hp Yamaha alongside, climbed back aboard, bringing with him the steering extension stick to clip on the life line. Now we could speed up or slow down at will from deck level.

Dinghy alongside, powering with nobody in it.

I actually enjoyed the ride, which I had not been looking forward to. I steered with my foot on the tiller while Michel readied the fenders and lines for docking. It was a calm and windless morning as we rode the incoming current up to the Stone Store where Alex and stepson took our lines. Here the United Carrier truck parked on the space saved for us by John Wood who had parked his car there. The operator braced the rig to take the load, then put out the claw-like hydraulic arm, and gently, skillfully lifted our half ton workhorse out of Magic Dragon's cockpit and onto the truck bed where he secured it on a nest of wooden blocks. The truck then drove across the Stone Store Bridge, and up to the Woods' boat shed. With its long proboscis fully extended, the skilled operator placed the Isuzu on the floor of the Wood Shed immediately under a chain hoist, hanging from a steel eye beam. Michel then rejoined me on the mother ship, and the two of us returned to home pilings the same way we had come up the river - with the dinghy tied alongside, by this time helped along by an outgoing current. We dropped the anchor, and pulled Magic Dragon back onto her pilings.

HiAb lifting the Isuzu.

The day after, Big Grunt ended up standing securely on wooden blocks on a sturdy metal table, ready to be opened up and diagnosed. Two days later Michel found that the cause of water in the oil was leaky frost plugs in the cylinder head, not replaced when he had replaced all the other frost plugs in 1984 simply because at the time he could not find the right size brass ones. The cylinders, pistons and bearing were still well within tolerance level. Had we taken the cylinder head cover off on the boat, the problem would have been obvious and we could have saved ourselves a great deal of work and money and perhaps got a few more years out of the engine as it was.

Engine in The Woodshed being lifted with Ken Wood's help.

Positioning engine.

Bubbles coming out of the frost plug, and also of Shelly and Ken sitting in the chairs after discovery.

Now that the engine was out of the boat we had to decide what to do next. A replacement engine would be very costly and would require many installation alterations. On the other hand, parts for the DA220 are still available from Klassen Diesel in Canada who sold us the engine. Unlike the modern high rpm engines of today, the DA220 is a long stroke heavy-duty motor with wet cylinder sleeves and removable valve guides and valve seats. It was designed to last and to be rebuilt when needed. Michel decided to do a thorough inspection while Big Grunt was off the boat and 'easy' to disassemble. At first he had feared that the water was leaking past the O-rings of the wet cylinder sleeves. To check the O-rings he had to remove the sleeves. As it turned out, the O-rings were in good condition, but the sleeves showed bad cavitation pitting, so that although the cylinder wear was not too bad it was time to replace the sleeves anyway. The valves had been ground four times over the years and they too needed replacing, as did the valve guides.

Ordering parts was easy, thanks to email. Cathay Air Freight had them flown to Auckland over the weekend via Singapore. However it took a week to get them from Auckland to Kerikeri, what with customs clearance and local road transport. We had ample time to disassemble and clean the engine and its various components. Without steam cleaning gear it all had to be done with engine degreaser solvent spray, a slower but effective option.

Treasure chest.

Once the NZ $5000 box of treasures finally arrived the crankshaft seals and the cylinder sleeves were soon installed, but while fitting the bearing shells it turned out that undersized con rod bearings had been shipped by mistake. On the phone Brent Klassen offered to send a standard set by air right away. That second set has not arrived in New Zealand yet. After we had been waiting for nearly three weeks Klassen sent a third set by FedEx and it arrived another eight days later. All that waiting turned out to be a blessing in disguise. It took the rush out of the job, enabling us to freshen up the engine compartment and to service or replace various systems aboard while we had the gift of time to do it all. We also had time to rebuild the fresh and salt water pumps, the heat exchanger, the alternators, and the starter, to check and adjust the gear box and to have the fuel injection pump and injectors tested.

Various stages of engine repair. New frost plugs...

New brushes for rebuilt starter...

New blood...

Cleaning engine compartment...

Paint jobs.

With the bearings on hand Michel was able to install the new pistons and finish the job with no major setbacks. He had to go and use the 50 ton press of a local machinist to extract and replace the valve guides in the cylinder head and the small end bushes in the con rods. Without a reemer and small honing tool, the bushes could not be fitted so had to be taken to an engine shop. It was a tiring exercise. Sleepless nights didn't help as Michel counted the possibilities for leaks should anything be left insufficiently tightened - fresh and salt water circulation joints, fuel and oil line joints, exhaust system joints, over eighty in all, he said. The job being needlessly extended caused him worry that he would forget what went where. It did not help to find a leftover O-ring at the end of the assembly. He poured over the engine manual and parts book schematics for hours without finding where the monster O-ring belonged. Someone may have planted it as a joke. It has been a puzzle. We were both exhausted by the end of the project.

Eelco in his inflatable, there to help when needed.

Retrieval of the rebuilt 'as new' engine went smoothly. We moved Magic Dragon as before, only this time with back-up hands, experienced ones, along for this second trip which was complicated by a bit more wind and stronger current. Magic Dragon needed a nudge out into the current by means of a push from their inflatable. But most importantly, our friend Eelco helped guide the engine back onto its four bolts, rather more difficult as the hydraulic hoist lacked a hanging cable to allow the load to be hand twirled. This one relies on the skill of the operator to make minute adjustments, and of someone to direct him with a loud enough voice to make himself heard. Eelco's voice box is as gigantic as is his six foot eight height.

Big Grunt gets gently placed back onto the engine bed.

Big Grunt started instantly when finally connected and ready, but it gave the mechanic a big scare by proceeding with a loud screech of grinding metal. We stopped it as soon as it had started. A close inspection showed nothing abnormal. We had to start it again to see what was the matter. The frightful screeching reoccurred, accompanied by sparks flying from the 12-volt alternator. It was the alternator cooling fan rubbing the alternator support bracket, an assembly misalignment. Needless to say it was with relief that we heard Big Grunt run smoothly and quietly on the third attempt. Still, it took a dive to clean the propeller and a few days of cruising around with Big Grunt faithfully on call to give us back our normal confidence in Magic Dragon's motoring abilities. In his youth, Michel had been a trained as a heavy duty diesel mechanic and had worked in that field for a few years. As in bicycle riding, it all came back to him.

Michel after having scrubbed the prop.