All of our curves

We recently had a request from a customer to show all of the power and torque curves of our VGT Series of engines on a single graph, for “at a glance” comparison purposes.



Take a look at the graph. Note how very flat power and torque curves are on our engines, and compare them to the curves of our competitors. The one below is for a Cummins QSB 6.7, medium intermittent duty (Comparable to VGT 450):

cummins torque 6.7


Note the spike in torque on the Cummins. Why does this matter? Well, the Cummins may have a higher maximum torque level, but it occurs at a spike, at a single RPM level. The VGT provides more torque, over a wider RPM range. This translates into lower cruising RPM (thus less fuel consumption) and more power at those speeds.


Choosing the right engine


Vessel design is a complex process, and every engine does not necessarily suit every project. Of course, Marinediesel would like to win every project out there in the market, but as manufacturers we understand that all engines are not necessarily created equal.

Some of the important points to consider when choosing an engine are listed below, along with some notes about the competitive advantage Marinediesel engines possess:

  • Power: Does the engine produce enough power and torque to get the job done? Marinediesel engines are usually best suited for small, high speed craft.
  • Weight: Lighter engines are best. Marinediesel’s VGT Series is the lightest engine in their class at a mere 515 kg.
  • Size: All the power in the world will not help you if the engine will not fit into a constricted space.
  • Cost: There is cost, and there is value. Marinediesel engines are usually not the cheapest, but they generally cost much less over the long term than those made by our competitors.
  • Operating Costs: Engines that require lots of maintenance, or difficult maintenance, cost far more over the long term. Our GM heritage means that our engines are reliable and easy to maintain.
  • Reliability: How much does vessel downtime cost you? Reliability pays big dividends over the long term.
  • Vibration: Excessive vibration reduces engine life and increases noise. The Marinediesel V8 beats every competitor hands down, no contest. An inline six cylinder engine can never produce less vibration. Don’t just take our word for it, though. It’s the physics.
  • Noise: Noise is uncomfortable on a pleasure boat. On a government boat, it can be deadly. What if the enemy hears you coming long before they can see you?




How does a heat exchanger work?


Your engine’s cooling system is highly critical; the combustion process produces an enormous amount of heat, and that heat must be removed or dissipated. If heat is not removed, cylinder and engine block damage may quickly result.

Heat exchangers cool the engine, but work a little differently and more efficiently than a simple raw water cooling system. A heat exchanger consists of a series of tubes, or coils, that fluid flows through. This fluid is enclosed (either cooland or distilled water). Additionally, marine heat exchangers are encased by a jacket, through which raw water (fresh water or sea water) flows through, cooling the enclosed fluid, removing the heat, and exiting the system through the exhaust. The minerals in sea water mean that scaling, or build up, can occur, which is why heat exchangers usually require periodic maintenance. Mineral build up drastically reduces the efficiency of the heat exchanger and thus, the cooling capacity.

This is also why a blocked strainer or faulty impeller quickly damages an engine. When blocked by debris (especially plastic bags), without the raw water to cool the enclosed system, the engine quickly overheats, sometimes in a matter of mere seconds.


New Product Announcement! VGT Axis Drive


Coming in January, 2016!

V8 500 VGT Turbocharged Diesel Marine Propulsion System “Axis Drive”

Caudwell Marine® Axis Drives are the world’s most technologically advanced marine propulsion system. The 500 VGT Axis Drive, designed for standard 13° transom installations, both available with left or right hand rotation propellers, is packed with innovative features not found in competitive drives.


This range of engines is designed to be as compact and lightweight as possible while maintaining durability and serviceability. They are intended for lightweight and high speed vessels and have a light duty rating.

• The aerodynamically efficient variable geometry turbocharger and the improved high pressure direct fuel injection system allow the 6.6 litre V8 to respond immediately and deliver smooth, consistent power, with a flat torque curve from 1 850 rpm all the way to the red line
• 4 valves per cylinder.

• Common Rail fuel injection.

• Variable geometry turbo.

• Safety warning systems monitor engine coolant temperature and level.

• Raw water flow is also monitored by exhaust temperature sensors.

• The engine’s closed cooling system gives improved corrosion resistance and minimizes the amount of flushing required after use.

• Raw water circulation is controlled by a belt driven rubber impeller pump, ensuring adequate water flow to the intercooler, heat exchanger, engine oil and power steering coolers.

• Both the engine and drive systems are controlled electronically by the NIRA Engine Control Unit (ECU).

• Electronically controlled variable geometry turbo to ensure excellent bottom end torque and performance.

• Gear train noise is minimized though using a CentaFlex Torsional damper system.

• Exhaust noise is reduced via routing exhaust gasses through the propeller hub.

power torque curve

The unique Axis Drive power train design is like a Pod drive mounted on the transom. It eliminates the universal joint as found in traditional stern drives, ensuring that power transfer from crankshaft to propeller is more direct and quiet, with less power loss at the propeller. Most importantly, it allows full power to be applied at all steering angles and trim angles.
The low drag bullet and pick up allow for high speeds.

The turning geometry of the patented integral axial steering system ensures safer high speed turns and exceptional handling characteristics at all speeds.

An electronically actuated dog clutch provides smooth, effortless gear selection controlled by the ECU.

A constant trim speed of 3 degrees per second, irrespective of load and speed. Trim range of -4 degrees to +33 degrees.

Installs using only 6 transom mounting bolts and 2 forward engine mounts, plus plug and play electronics make it the quickest and easiest installation possible

• Through prop exhaust
• Integral Raw Water pick up
• Dual power assisted and direct helm hydraulic steering
• Chrome plated styling covers
• Integrated hall effect sensing for steering and trim angles offering closed loop feedback for digital docking control
• Dry sump main gearbox
• Low drag anti-cavitating lower unit hydrodynamic profile
• Integrated oil temperature and pressure sensing for the gearbox
• Anti – log strike shear protection for the lower unit.
• 64 degree turning arc.

To read more about the Axis Drive, check out our catalogue listing or MD_V8 500 VGT Axisdrive Product Bulletin. Remember, though not available until January, speak with your local Marinediesel distributor today and indicate that you would like to be one of the first to try this new and innovative drive system!

Introducing the all new Marinediesel Website


Today, we are proud to debut our all new website for Marinediesel customers.

We have tried to put as much information as we can on this site, with lots of video, pictures, and downloads for your use. Some of the new features of the site include:

A brand new, more accurate dealer locator.

New videos (Coming soon, detailed maintenance videos)

A brand new product catalogue

Customized login and newsletter subscription

New ways to contact us and communicate with us

Multiple language versions of the site (Native translations. Bahasa Indonesia Indonesia-Flag-16 and Vietnamese Vietnam-Flag-16 now, with Simplified Chinese China-Flag-16, Arabic Saudi-Arabia-Flag-16, Korean Korea-Flag-16, Thai Thailand-Flag-16, and Burmese Myanmar-16 coming soon)

We hope you enjoy some of these new features and we look forward to receiving your feedback and suggestions.