Dual Yanmar V8s Sterndrives Gives New Spirit to Sports Cruiser

Brad Hays 1
The joy of buying a 2002 model Riviera M430 sports cruiser was short lived for Gold Coast boater Brad Hay when one of the original diesel engines failed soon after taking delivery.

As is sometimes the case, the starboard engine failed and Brad was facing a hefty bill for a re-build.  After considering all the options, Brad decided to completely re-power his boat with a pair of the new Yanmar 8LV diesel sterndrive engines, complete with Yanmar
ZT370 sterndrive legs.

“My choice was to rebuild one engine and still have a pair of old engines in my boat, or repower completely and start with fresh engines,”
Brad Hay said.  “Ultimately I chose to go with a pair of new engines for the security and confidence.”

Having spent much of his life in and around a variety of sports and blue water fishing boats, Brad had the benefit of established boating knowledge behind him.  Brad is also a qualified scuba dive instructor.  He looked at the option of a straight swap, retaining the same brand of engine that had failed him.  But that turned out to be a more expensive option than going for a fresh pair of Yanmar 8LV diesel engines.

“I did my homework on the Yanmar 8LVs and was very happy with the information that I gathered,” Brad said.

“Compared to my old 6 cylinder diesel engines, the new Yanmar V8 configuration stacked up really well.  The Yanmars are a compact and tidy configuration which would easily fit into the engine bay.”

“Just as important, were the word of mouth referrals that I got back from other boaties.  I already knew that the Yanmars have an impressive reputation for being strong, bullet proof marine engines, but talking to people who owned Yanmars, I received the strongest endorsement possible.”
Brad Hays 2
“That was enough for me, so I ordered a pair and got the job under way. Being a different configuration to the old engines required new engine beds to be laid in the Riviera and the transom modified to take the Yanmar ZT370 transom plate.”

The entire project from assessment and quoting through to installation and then re-launch was expertly handled by the local Yanmar authorised Dealer, George Mansell, and his technical team from Onshore Marine at Horizon Shores Marina.  While Onshore Marine have extensive experience with Yanmar, this was their first opportunity to install this new 8LV model and the new integrated Yanmar “easy fit” instrumentation and control system.

The Yanmar 8LV is offered in two configurations, the 320 mhp (235kW) model the 8LV320, and 370 mhp (272 kW) the 8LV370.  Brad Hay selected the 8LV370 which delivered an additional 70 mhp per engine over his old engines.

At the heart of the new Yanmar 8LV is a 90°, V8 cylinder block.  It features twin turbo chargers and direct injection with a common rail fuel system.   There are four valves per cylinder.  Tipping the scales at just 435 kgs dry weight without gearbox, this Yanmar continues in tradition of delivering high power from a low weight package.

The new Yanmar ZT370 sterndrive has been specifically designed and built to mate to the Yanmar 8LV.   The quiet hydrodynamic ZT370 clutch delivers exceptional smoothness during gear shifting.  Precision forged gears deliver long life and the two counter rotating propellers have been purpose matched for superb acceleration and tight hold tracking.

All up the job took 6 weeks and the boat was ready for sea trials.  At re-launch the boat was as good as a factory production fit.   The Yanmar 8LV looks as though it was specifically chosen for this model Riviera with all the service point s readily accessible.

“I’m blown away with the new Yanmar 8LV engines,” Brad Hay said.   “They have certainly exceeded all my expectations.  They are a compact and tidy unit and easy to access for routine checking and servicing.”

“One of the best things about buying Yanmar is that their factory technicians worked together with the local dealer to sea trial the boat before signing off on the installation.   Not only is this a great quality checking procedure on the installation, but the staff involved went to a lot of effort to ensure that the propeller selection was absolutely correct.”

“This really impressed me.”

The Riviera M430 finished up with a pair of 26” pitch propellers which at wide open throttle delivered a top speed of 33.5 knots.  Optimum cruising speed of 22.4 knots is achieved at 3200 rpm with fuel consumption recorded as 43.5 litres per hour.

Comparing the before and after, Brad Hay is more than happy.    He has an extra 150hp available, with engines which weight 250 kgs less.  He has a higher top end speed and much improved cruise speed which has all been delivered without any increase in fuel consumption.

And as a self confessed tech-head, Brad Hay is more than happy with the new Yanmar Can Bus equipped VCS (vessel control system) which provides a full factory supplied and warranted throttle, gear shift and engine instrumentation package.

“The only thing that I missed out on was Yanmar’s new Joystick Control System which was not available when I re-powered.  It would have been really neat to have this on board to round out the perfect package.”

“I may have had some bad luck soon after buying my Riviera, but as things have now turned out, I could not be happier with my, now Yanmar powered, boat.”