Beta BV3800 (November 2005)

Beta Marine's BV3800 is a logical successor to the Perkins 4-236 and 80hp Ford Lehman diesels engines, reports Andrew Norton

Through the 1960s to the early 80s, a popular choice of engine for displacement-hulled cruisers to 12m was the Perkins 4-236, a four-cylinder version of the ubiquitous 6-354. This was also available in a straight turbocharged model (the HT6-354 horizontal engine) that was fitted to the shaftdrive 9.4m planing-hulled workboats built by Swiftcraft for the Royal Australian Navy.

The naturally-aspirated direct-injection 4-236 developed 76hp continuous at 2250rpm from 3860cc of piston displacement and produced a peak torque output of 250Nm at 1600 revs. Complete with a 2:1 hydraulically operated gearbox and heat exchanger cooling the dry weight was 519kg.

The 4-236 was widely used by UK boatbuilders and fitted to larger motorsailers, like the Salar 40 sloop launched in 1965, one of the bigger fibreglass hulls of its day.

In Australia the 80hp Ford Lehman diesel was a popular variant of the 4-236 and was the standard power for Halvorsen's single-engined Island Gypsy 30. When twins were specified for the Island Gypsy 32 they were usually 80s.

A mate of mine had an 80hp Lehman in his 12.2m displacement cruiser and the hull easily achieved eight knots or cruised all day at seven. Because of the maximum power being developed at low revs the engine was unobtrusive at all but Wide Open Throttle revs, although being such a big displacement four the vibration levels were high at low revs.

Unfortunately spares for the Perkins and Lehman are rapidly becoming scarce and until recently this has been a problem for owners of displacement cruisers and motorsailers wishing to repower their hulls. Opting for a much higher revving engine and gearing it down doesn't really suit the character of older timber hulls, where an engine ticking away at 2000 revs is much more enjoyable.

The successor
According to Beta Diesel Australia, its recently-released BV3800 has been well received by owners of older hulls. One has been installed in a 16.2m ketch and another in a commercial fishing boat, both in Tasmania.

Based on a Kubota tractor/industrial engine and marinised by UK-based Beta Marine, the four-cylinder naturally-aspirated BV3800 was released in Europe in 2004. It displaces 3769cc and has a cylinder bore of 100mm and piston stroke of 120mm, but unlike the BV3300 reviewed last issue in Trade-A-Boat, the 3800 has direct injection and four valves per cylinder, whereas the 4-236 had two. Like the 4-236 the BV3800 has a gear-driven camshaft with pushrod valve actuation and a gear-driven sea water cooling pump for reliability and reduced maintenance.

To comply with US Tier 3 exhaust emission regulations without opting for electronic engine management the BV3800 has E-CDIS, which loosely translates as Emission-compliant Central Direct Injection System, where the fuel injector is located centrally in the combustion chamber surrounded by the two inlet and two exhaust valves. This ensures a thorough air/fuel burn and substantially reduces emissions while increasing power over comparable indirect injection engines.

Although the piston displacement is two per cent less than the 4-236 the BV3800 develops a maximum of 90hp (crankshaft) at 2600 revs. Beta Marine says that an eight per cent allowance must be made for losses in the standard hydraulic gearboxes fitted, reducing the maximum shaft horsepower to 82.8 and the continuous rating to 78.2.

However the BV3800 produces a lot more torque and the peak output is 285Nm at only 1500 revs. At 1600 revs the torque is still 283Nm versus 250 at the same revs for the 4-236, although from then on the torque starts to fall off rapidly: at 2600rpm the output is down to 230Nm - so really the BV3800 performs best below 2200 revs.

As with its BV3300 counterpart the BV3800 is fuel efficient for its output and based on a standard prop power curve it uses 1.4lt/h at 800rpm up to 10.4lt/h at 2200rpm, where the engine can still develop 85hp at the crankshaft. Above these revs the consumption rises considerably as the prop power and full load output curves converge, although at these revs the fuel flow is still only two per cent greater than the 2.2lt turbo-intercooled Volvo Penta D2-75 which develops 73.7hp at 3000rpm and 212Nm at 1800rpm.

Less weight
Unlike its smaller diesels Beta Marine doesn't specify a combined engine and gearbox weight for the BV3800 but the standard hydraulic PRM 260 box should add around 50kg to the bobtail engine weight of 392kg, still keeping the overall weight to 15 per cent below that of the 4-236.

With the PRM 260 box the BV3800 is 1133mm long, 550mm wide and 762mm high to the top of the raised dry-element air intake filter. The 65A 12V alternator is mounted almost at rocker cover height forward of the heat exchanger expansion tank and the starter motor is well above the engine mounting feet. A brass sump drain pump is standard with the outlet at the same height as the engine oil dipstick, at the top of the engine.

Options include a 100A alternator or 3.5 and 7.0 kVA 230V 50 Hz engine-driven alternators, useful for providing onboard appliances power at sea without running an auxiliary generator. Beta Marine can also fit a hydraulic pump for operating a bowthruster and keel cooling with a dry exhaust system is available, while for heavier-duty applications PRM 500 and ZF gearboxes can be fitted.

For information contact Glenn Townsend at Beta Diesel Australia on (02) 9525 1878.

PERFORMANCE
REVS (rpm)	TORQUE (Nm)	FUEL CONSUMPTION (lt/h)
800	265	1.4
1000	273	1.6
1200	280	2.1
1400	283	3.0
1500	285	3.8
1600	283	4.5
1800	275	6.0
2000	260	7.5
2200	255	10.4
2400	245	13.6
2600	230	18.0

Published : Tuesday, 1 November 2005
Issue : November 2005

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Prices and specifications supplied are for the market in Australia only and were correct at time of first publication. BoatPoint Australia makes no warranty as to the accuracy of specifications or prices. Please check with manufacturer or local dealer for current pricing and specifications.