When a sudden coolant loss threatened his sailing, Andy Du Port realized it was time to replace his yacht’s old Volvo Penta engine.
These engines, once called auxiliaries, were noisy, hot, smelly metal masses that often lacked the power to cruise against wind or tide. My first yacht, a single-cylinder Stuart Turner petrol model I procured in 1979, had a mere three moving components. It misbehaved on the starboard tack but still responded unexpectedly well to a shouted demand when its performance dipped.
This engine produced less power than a standard lawn mower and, if put in reverse 20 yards from its berth (metric measurements had yet to be introduced), there was a fair chance the boat would halt before causing severe damage. On the plus side, it was simple to maintain and could be taken home in the car’s trunk.
My second vessel, an aged 28ft Twister, was fitted with an unreliable two-cylinder petrol engine that I quickly swapped for a brand new Bukh 10 diesel, effectively doubling the horsepower. Basic maintenance remained manageable – a wrench and a hammer could tackle most issues.
Then engines became more advanced, and the price of spare components soared. After owning two more boats with slightly more potent engines, we purchased Kudu, a Hallberg-Rassy 34, in 2005. Its original 1998 29hp Volvo Penta MD2030B seemed outdated today, but aside from changing oil, filters, and hoses, professional help was frequently required. Therefore, near the end of the 2021 sailing season, the saga began…
Kudu’s original 1998 Volvo Penta MD2030B diesel engine showing its age
Coolant Issues
The first warning sign was a slight coolant drop. Even though I regularly changed it, I hadn’t previously needed to top it off between seasons. Now the coolant level sank to the saltwater tube in the heat exchanger every three to five hours.
I was urged to meticulously inspect all hoses on the freshwater pump. Upon removing one, I discovered the brass fittings were almost entirely corroded, requiring a new pump. However, my optimism that issues were resolved was short-lived, as coolant continued to vanish.
We then checked the entire coolant system, replacing multiple parts, including heat exchanger end caps and the thermostat. While coolant loss appeared lower, it still needed daily topping up, and I doubted we could run for more than six hours without addressing it. Topping off a hot engine isn’t safe, limiting our ability to undertake long sails, such as Channel crossings on calm days.
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Grey Smoke
The next issue was difficulty starting the engine.
The battery was fine and the starter motor turned normally, but it needed more cranking than usual and ran roughly while emitting grey smoke before stabilizing. After consulting my engineer, Steve, we diagnosed a faulty glow plug in need of replacement. This would usually be a simple job, but it was stuck in the block and broke off instead.
Fortunately, the remaining piece did not hinder engine operation, and after testing the other two glow plugs, we decided to wait until we could remove the cylinder head to drill out the remnants. The engine ran smoothly in a short winter trial, giving us confidence that the problem was resolved.
The old engine’s cylinder head removed
Stay or Leave?
Once the boat was back in the water, we put the engine through multiple runs. Starting improved but still involved some coughing and a puff of grey smoke. Starting was notably more challenging when the engine was warm. In the meantime, we kept sailing as Steve pondered the situation.
He suggested the injectors and injector fuel pump be examined by a diesel specialist.
This recommendation caused delays in starting our summer cruise. Nonetheless, everything was reassembled by the second week of June, and we faced the choice of continuing with our plans to sail to the Netherlands.
The engine did seem to start more easily when cold, but coolant loss remained a concern, particularly with multiple long passages and potential motoring on the Dutch waters. Ultimately, we decided to go.
The new Beta 25 engine, still in its box, weighing in at 260lbs (118kg)
Crossing the Channel
After sailing from Gosport to Eastbourne and then to Calais, the rest of our journey seemed possible. Shortly after arriving in Nieuwpoort from Calais, we had to change berths. The engine remained at normal operating temperature but was quite reluctant to start, prompting doubts about heading east. Gales further delayed us, and time was slipping away. Thus, with reluctance, we returned home.
Back in Gosport, the engine still didn’t operate correctly. Steve suspected a coolant leak into the oil sump. He mentioned the possibility of the engine having overheated and the cylinder head becoming slightly warped.
After a few more hours of operation, it was clear coolant loss persisted, and the engine remained hesitant to start when warm. A choice had to be made – continue investing money in repairs or take the plunge and buy a new engine? We opted for a new engine.
A marine electrical engineer installed a voltage-sensitive relay
Conversion Kit
A new Volvo Penta engine wouldn’t fit Kudu’s existing saildrive, prompting a search for an alternative brand that would match both the saildrive and space requirements. Though we considered a refurbished engine, we were strongly advised against it if we wanted reliable, long-lasting performance.
A friend alerted me to Beta Marine, which produces conversion kits allowing their engines to connect to Volvo Penta saildrives. They also offer custom mounting brackets fitting existing engine supports. After further research and discussions with several Beta owners, I ordered a Beta 30.
Once the new Beta 25 was lined up with the saildrive, the rest of the installation was straightforward
Out with the Old
Before building the feet, Beta required precise measurements from the face of the saildrive to the existing holes in the bearers. We soon understood that accurate measurements for the new mounts to align precisely were impossible. While measuring, we realized the Beta 30 would fit very tightly, possibly needing unattractive modifications to the companionway steps. To be cautious, I changed my order to the slightly smaller Beta 25.
When the new engine arrived, Kudu was lifted out to prepare for installation. Within a week, Steve had taken out the old engine and hoisted the new one aboard. The rest of the installation was relatively simple:
The new engine was aligned with the saildrive, then briefly moved for the holes to be drilled in the bearers.
New hoses for the calorifier were purchased.
A Vetus air vent (anti-siphon for the saltwater system) was fitted.
The large old Volvo Penta silencer was replaced with a much more compact Vetus silencer/waterlock.
Andy kept the original three-bladed folding propeller which was matched to the old Volvo Penta MD2030
Timed Runs
While Steve worked below, I installed the new control panel in the cockpit. Even though it was the same size, the Volvo Penta panel was offset in the casing for the ‘Stop’ lever (the Beta has a more streamlined push button), so I took the opportunity to align everything neatly.
A bit of sawing, drilling, and using a plastic cutting board finished the job. Upon connecting the wiring loom to the engine, we found it was slightly too short, so an extension was promptly ordered from Beta Marine. Eventually, everything was complete, and we fired up the engine for the first time, using a hose to supply the saltwater cooling system. After launching, the engine roared to life as soon as I turned the key. We were finally back on the water.
After 15 minutes idling at one-third throttle, we untied and executed a series of timed runs at varying throttle settings. The engine reached 3,300rpm without producing smoke, and Beta confirmed that this was acceptable as long as I monitored the temperature alarm during full power use. Cruising revs of 2,250-2,500rpm yielded a comfortable speed through the water of 6 to 6.5 knots.
Andy spent just under £8,000 on the re-engining of his Hallberg-Rassy 34
Alternator Charging
One difference between Volvo Penta and Beta concerns the wiring for alternator battery charging. Volvo Penta engines charge both domestic and engine batteries through a split charge diode; Beta engines only charge the engine starting battery.
To charge the domestic batteries in this setup, all batteries must be connected while the engine is running, and then it’s crucial to disconnect them to prevent unintentionally draining the engine starting battery while sailing. Fortunately, the solution proved simple. A local marine electrical engineer installed a voltage-sensitive relay – a two-inch cube sitting beside the battery box that apparently requires no further attention.
Costs Incurred
The project’s total cost (new engine, replacement parts, and installation) was just under £8,000, though I recouped around £1,000 by selling the old engine and various unnecessary Volvo Penta parts, like a brand-new exhaust elbow. Long-term savings are anticipated due to the significantly lower cost of Beta filters, impellers, and other consumables.
With a bit of luck, after many frustrating months, Kudu now boasts a reliable engine that should serve her well for years ahead.
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