» » » Propping the Cummins 6CTA 8.3 480CE vs. 430/450 Diamond Engine

Propping the Cummins 6CTA 8.3 480CE vs. 430/450 Diamond Engine

The Cummins Marine 6CTA 8.3-M4 “480CE” Story

Cummins Marine 6CTA 8.3-M4 480C-E Engine
Cummins Marine 6CTA 8.3-M4 480C-E Engine

The Cummins marine 6CTA 8.3-M4 480CE engine has had a colorful history to say the least. Back in the early 2000’s Cummins produced the 480C-E “hybrid” version from the 430/450 diamond mechanical engine. By adding an ECM and other improved electronics, boosted the base horsepower from 430 BHP to a whopping 465 BHP all while using the EXACT same block and internal mechanical components. This engine, now suped-up to impress any and every boater in the pleasure boating world was ready to hit the stage. Big boat builders such as Sea-Ray and Tiara to name a few began placing these engines in their boats and propped the boats to impress… and impress they did. However, as boats almost always do, they get heavier, bottoms get dirtier, windage goes up and so on… and the required amount of fuel required to burn to achieve the same RPM increases, which ultimately adds more stress and load to the engines over time.

Cummins 6CTA 8.3 480CE Run HARD
Cummins 6CTA 8.3 480CE Run HARD
Cummins 480CE Burnt Turbo
Not even the turbo can handle all of the extra heat!
480CE dropped valve damage
Damage from dropped valve and/or valve seat

The infamous 480CE “Dropped Valve”

Internally, the 480CE cannot handle any more load than the 430/450 Diamond – the colorful history of the “hopped-up version” of the 450 Diamond says that without any doubt. All you have to do is see how many engines drop valves and then compare the two engines. Since the head and other engine components were never modified to accommodate the increased horsepower of the engine, the valves and valve seats seem to take the brunt of the abuse and as a result end up meeting “face-to-face” with the pistons inside the combustion chamber, need less to say, the result is not pretty and not cheap $$$! The trick to a long lasting engine is propping the boat correctly so as to NOT overload the engine… more loading = more heat = more stress = catastrophic failure.

Cummins 480CE Dropped Valve Damage
Cummins 480CE Dropped Valve Damage
Cummins 480CE Dropped Valve Damage
Cummins 480CE Dropped Valve Damage
Cummins 480CE Dropped Valve Damage
Cummins 480CE Dropped Valve Damage

The Solution for a Long Engine Life

Look at the fuel & load curves below… If you are loading the engine above the 450 Diamond curve in the “cruise RPM zone”, then IMO, you are at serious risk. They key is to just think of your 480CE engine as a 450 Diamond, prop it to stay at or below that load curve, especially in the “cruise zone” and you have done it right. Damage has occurred in the past as to over stressing the valves, etc., cannot be undone, but at least from here forward, you have done all you can do…

Here’s the bottom line: If you cannot get your load close to the 450 Diamonds curve and be happy with the performance, then you have what we call, “too much boat and not enough engine” And lastly, think about where all of the wear and tear takes place on these engine – It’s not at WOT, it’s at CRUISE!

480CE vs 450 Diamond Fuel Curves
480CE vs 450 Diamond Fuel Curves

 

Corey Schmidt – June 1016