Tony has some excellent references under “Tony’s Tips,” https://www.sbmar.com/articles/cummins-marine-aftercooler-maintenance/
The air side will be visible when you pull the aftercooler core.Ā The air side can get dirty from oil blowby, salt, and whatever else might be floating air in your engine room.
When talking about marine diesels, the heat exchanger refers to the engine cooling system (exchanges heat from engine coolant to raw water), the aftercooler refers to post turbo air cooler (exchanges heat from compressed air to raw water).Ā Your issue could relate to the aftercooler being dirty on the air side or low raw water flow through the aftercooler.
Can you get a 1 or 2 gallon plastic bag (tough ziplock freezer bag?) around it?
Hi Richard,
I will defer to all things technical on this engine to Tony.
I also fish in BB and keep a close eye on the new boats getting built. The QSC600 has only come to the bay in the last few years, so the fleet is on the steep part of the learning curve. I would try to get a hold of other QSC600 owners that have installed new or repowered to see how they are running them. Certainly staying below the propeller consumption curve under steady state load is a good start. I assume Cummins Northwest is supplying the QSC600 engines to the Washington builders.
Sorry to hear about your failure, it is the first major one I have heard of. Could have been a bad luck manufacturing defect. Do you have any warranty left?
Scott
“Diamond 330” is 315 bhp. (330 was the marketing number)
Engine choice aside, is 600-715 hp enough power to do what you want? Doesn’t seem like enough HP for that big of a planing boat. I would like 2X QSC’s, but that is just me:)
What gear ratio? Which 6BTA do you have?
Not sure who did it, but I know there are some Shore boats in the Bay that installed the 305 HP 5.9 QSB with good results with the same setup. That is the max HP that can be keelcooled with jacket water in the aftercooler, as far as I know.
Some googling results shows 28-30 psi @ 2600 RPM. Have you plotted PSI and EGT versus RPM? Does it get on plane easily?
Sorry this is being difficult for you on the idle side. I have not worked with an electronic Cummins, only mechanical Cummins or newer Volvo/Deere.
What alternator do you have now? Internal or external regulator (what type)? I used to work in a marine electrical store, might be additional setup options.
Sorry, no help on your idle issue.
Can you install a smaller pulley on the alternator?
Are you looking at the propeller demand curves or the full throttle curves? Propeller demand curve is probably the better comparison and will make your numbers easier to interpret.
That was about the only place I figured it would be below freezing for so long!
Dare I ask where this boat is being stored?
We lay up ~10 months a year in AK with similar regimen to Rob, but is only below freezing <6 months a year. Our biggest problem is blowing sand in 100 mph wind off the tundra in winter. The sand gets in any nook and cranny. We also wrap our windows and any exposed rubber or plastics. Foam is used to block some vents to allow some air circulation.
Put the batteries away charged and charge them fully before using them.
How about exhaust and intake? We seal the dry exhaust, don’t know about the air filter.
What does it look like from the mixer to the muffler?
Can you post the oil test reports from CAT?
How did you measure draw? Ammeter?
Just start doing it yourself with a buddy, watch your ammeter and have a buddy turn of all breakers/switches/equipment one by one and watch for changes. Even if you can’t find the exact source, you can narrow it down a lot.
Just a side note, our Volvo D13 has a “seawater” pressure alarm after the pump, even though it is on a closed loop circuit for the aftercooler. Not sure what the trigger point for the alarm is.
Going to dip my toe in here….hopefully I can delete if I am totally wrong.
Keel cooling with regards to aftercoolers covers a couple options, JW (jacket water) keelcooling is a single circuit where the block and aftercooler share the same circuit. Or, LTA (low temperature aftercooling), LTA refers to a totally separate dedicated keelcooling loop for the aftercooler, not shared with the engine.
If you are going for a heat exchanger, I would assume you would go SWAC, but that is just a guess.
Our 6BTA has a keelcooler for the engine, and seawater system for aftercooler. Our D13 Volvo has two keelcoolers, one for the engine, one for the aftercooler.
My 2 cents, Tony can correct me if I am way off base I will crawl back to lurker status:)
I would assume WET QSM always means coolant cooled manifold and turbo, but certainly check with your distributor.
aftercooler?
