Page created by T Apr 20th 2007:
Back to Marine Holdens
==Marine Holdens:== ===History:===
Submission by The Red Baron Apr 21st 2007:
Boat builders have been using Holden engines in their hulls in Australia since the 1950's. Various companies have been manufacturing marine conversion kits for these applications since then also (companies include ROLCO and TAWCO). As cast iron blocks don't react well to salt water (from the bay / ocean) running through them the majority of Holden engines went into ski boats designed for use in Australia's rivers and lakes.
===Most Common Usage:===
The most common Holden engines used in ski boats were either red 6's or V8's. There are various installation configurations with most being mid-mount (the engine is mounted in the centre of the boats hull). As ski boats have such low sides and sit so low in the water it was necessary (for aesthetics) to mount the engine as low into the boats hull as possible. The engineers of the day figured that the best way to do this would be to mount the engine in the hull backwards. (the centre of the crank is much closer to the bottom of the motor at the front of the crank compared with the rear of the crank....mainly due to the flywheel being in the way).
===Drive Train:===Gearbox's were not commonly used on these motors and a stop / go system was used predomininantly - called a dog-clutch. The basic principal is as follows. On the front of the crank a steel gear is used with 3 castle type teeth on the front of it. The dog-clutch assembly replaces the timing cover and contains another gear similar to the castle type one on the crank. This is connected via a prop shaft to the boats propellor. Linkages link the dog clutch gear via a rod back to the boat driver. When the driver engages gear the linkages force the two castle gears together transmitting drive to the boats prop.
===Manifolds:===For safety reasons the engineers of the day also decided it would not be a good idea to have red hot exhaust manifolds so close to the boat occupants (usually only separated by a fiberglass or timber engine cover). They therefore designed what is by far the most interesting part of the installation - the cooling system.
On the base of the boat is a pickup which is aimed towards the front of the boat - thereby increasing the amount of water forced in as the boats speed increases. This runs through a rubber hose into an inlet on the engines sump which passes the water through a copper coil cooling the engine oil. It then runs via an outlet and another hose to an externally mounted high volume belt-driven water pump which runs off a pulley on the flywheel.
From the water pump it runs into the inlet of the water cooled exhaust manifold and then out the outlet and into the engine block from a custom inlet made to cover where the car water pump would sit. The fresh water then works its way through the engine block and head and out an outlet on the cylinder head. From here it runs into the exhaust manifold and out of the boats exhaust pipe.
This serves the dual purpose of returning the now hot water back the outside of the boat and it also cools the exhaust pipe. It is a very efficient and effective system. It is actually cool to touch the block and exhaust manifold after its been running for hours on end!
Refer to the attached pictures for a visual indicator of the above.
===Current Trends:=== In todays ski boats, Mercruiser EFI V8's are used which are a marinised Chev 5.7ltr similar to the V8's used in the new Commodores. General Motors is the parent company of Mercruiser, Chevrolet and Holden.
There are some applications where Holden engines have been used in fishing boats for the bay / ocean but they use a heat exchanger system. This is a similar theory to a cars radiator. There is a tank in the hull of the boat which has a copper coil running from the motor immersed in a tank full of water from the ocean.
Written by The Red Baron. Please feel free to add.
End of submission by The Red Baron