I'm in the process of purchasing either an 05' Sea Ray 420 Sundancer or an 06' Sea Ray 44 Sundancer. The main difference, besides increased price, is the upgrade from the 480CEs to the "common rail" QSC500s. My question is what are the advantages of going to the 500s (besides increase in horsepower) and is it worth the price jump to the 06' (appx 20% increase on average). I've been told the QSC 500s are a much better motor but no one has explained why and what negatives exist in the 480s. Thanks. Any insight would be appreciated.
Hi, Welcome to Yacht Forums. There is a member here with a lot of Cummins experience called sbmar, he posts a lot of tech stuff at Boat Diesel.com and has a website http://www.sbmar.com/
The 480's are good motors and the only issue I know of with them is there is a small hose that connects to the turbo that likes to go bad every couple of years and blow off of the turbo. It's a cheap hose like a 14" long 1 1/4" rubber hose and I think goes from the turbo to the bypass, but cannot remember anymore. Just change them every 2 years and save an old one as a spare. The 500 common rails are a little bit quieter and smoother running, a little more fuel efficient. But the only major thing you gain is the smart craft gauge system that shows you current fuel consumption and a few other things. I wouldn't mind owning either engine, and if the boats exactly the same, wouldn't say the one with common rails is worth the extra 20% all things being equal.
Hi, You might find that the hose described above is actually connected to the Air Fuel Ratio control on a non electronic engine. It will let the manifold boost pressure govern how far the fuel rack will open with low boost pressure thus keeping the black smoke down under acceleration.