Cat Upgrades 3126 Marine Diesel

Diesel Progress North American Edition, August, 2001 by Mike Osenga

The newly formed Caterpillar Marine Division has introduced an upgrade to one of its primary pleasure boat marine engines with the hunch of the 3126B marine diesel. The new model is totally electronic and will be available with 420 bhp and 450 bhp ratings at 2800 rpm. Cat said the engine conforms to IMO January 1, 2000 regulations.

In April, Caterpillar announced it was forming a Marine Division, combining the Caterpillar, MaK and Perkins-Sabre brand names into a separate marine business within the Engine Products Division. The overall marine product line represented by that new organization covers 63 lip to 22,000 hp in commercial and pleasure marine applications. John Phipps has been named director of the marine division and Jan Arnold as manager of marine products, systems & partnerships.

The new 3126B diesel will feature Caterpillar's HEUI fuel system and is controlled by a Cat electronic control module (ECM). This is the second time Cat has used HEUI on a pleasure boat marine engine with the 3126B joining the 3412E as HEUI engines.

The HEUI system also uses a high-pressure oil pump to pressurize fuel at the injector, as opposed to a traditional cam-drive rocker arm. This, said Cat, provides full injection pressure at 40 percent rated engine speed, for better fuel atomization and more complete fuel burn.

The ECM has a new faster, more powerful processor and software and software control maps are written to maximize power and torque while meeting IMO [NO.sub.x] regulations. Further, the ECM can handle multiple engine synchronization.

There are also changes to the air system, including a new wastegate turbocharger, as well as a new cylinder head design. Cat said these design changes give the 3126B better low end power development for rapid acceleration, especially for performance craft to quickly reach planing speed. The turbo mount has also been moved from mid-engine to the rear of the engine, which is common on larger Cat engines.

Also, the heat exchanger and expansion tank have been moved to the side of the engine reducing the overall installation length.

The cylinder head is a three-valve, cross-flow head first introduced on 3126B truck engines in 1998. The head has two intake ports per cylinder on the right side of the engines and a single exhaust port per cylinder on the left side.

These changes, Cat said, gives the 3126B high levels of reserve power and torque to handle the added load from increased throttle speed, wind, waves, currents and power turns.

On the service side, HEUI self-adjusts the fuel rack and timing settings. A new serpentine multirib belt drives the water pump and alternator with tension adjusted automatically. Electronic diagnostics improves the engine information available to the pilot and service personnel, Cat said.

The 3126B is fitted with an engine-mounted control panel and is compatible with all Cat's electronic pilothouse monitoring systems including the recently announced Marine Power Display and Cat Engine Vision system.

Looking Good -- Cat Offers Custom Paint & Appearance Options

The pleasure boat marine business is largely a bout style and performance. Look good and go fast.

With this in mind Caterpillar has introduced a new custom paint process, as well as other appearance improvement options for its 3412E, 3406E or 3196 marine propulsion engines.

A high-grade, ultra-smooth polyurethane paint in Caterpillar Yellow Matterhorn White and Cloud White, as well as almost any other color, is now available for Cat's Marine Division. Heat-sensitive components receive a textured black finish. A chrome breather is also available as an option.

For a cleaner overall look, Cat said it has rerouted the wiring harness and is leaving the black hoses and belts unpainted. There is also a new special shipping container that has no contact with the engine.