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Picked up a 35′ Carolina Classic with a pair of Cummins 480CEs with 3,500 hours. At WOT Port Motor maxes at 2,510 RPM with 61 pounds of Boost Pressure and Crankcase Pressure of 3.26″. Starboard 2,540 RPM with 65 pounds of Boost Pressure and 1.98″ of Crankcase Pressure. Props are 24 x 30s and everything I’ve come across says those are the right choice for my set up. Marina scale weighed the boat at 30,000 lbs and the hull was powerwashed clean. Boat came with an extra set of 24 x 32 props so the prior owner made the move to drop to a lower pitch.
From what I understand I should be getting ~2,680 RPM and in the 30s for Boost Pressure out of each engine at WOT.
Anyway, I ended up pulling both heads and found they both had cracks between the intake and exhaust valves – each on multiple cylinders. New heads are now on both engines. Cylinder walls look great and are in spec. I have gone through the aftercoolers which had some soot but not bad. Regardless after a dozen cans of brake cleaner and everything else Tony recommends, they are in great shape.
So one other item I am not sure about is the Wastegate Valves. I put together a test device and put 26 PSI into each and they travel a little less than 1.2″ each. The book says they should travel 2″ at 26 PSI. Given that, I’m wondering if they are tired after 12 years. The part that makes me wonder if they are OK is that they both are doing the same thing. The question is should I replace the Wastegate Valves? Any feedback is appreciated!
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