Another Repower Question

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PJ

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I have Cummins 5.9 6bt's 1993 version they are getting weak and I have blow by. The wot rpms have dropped by 100 rpm it is now 2700, from 2800 and I have black soot on the aft section of the boat. They used about 5 quarts of oil running to Marathon from SC. I have a quote from a Cummins dealer for the engine's and ZF transmissions for $56,322.04 less install for two new 6bta's 330 hp. We love the boat but money and resale value are an issue.
Home port is Charleston SC we are currently in Marathon FL

Question 1 is it possible to rebuild the current engine?
Question 2 what will happen if I keep running them the way they are?
Question 3 If I decide to re-power, I can save money by not getting new transmissions would that be wise?
Thanks
Paul
Ocean Maid Carver 370 Aft Cabin
Marathon FL
 
Having been there and done that, I can tell you, if resale value is a concern to you, don't do it. You will NOT recoup repower costs when you sell the boat. The only way to in any way recover the costs is to keep the boat forever and use it a lot.

By the numbers, you are much better off to sell the boat as is and buy another boat that has already been repowered or is a newer boat.

Bob
 
Keep in mind the not-included installation costs can be very substantial plus that will also likely entail new prop shafts to deal with revealed wear/scoring and because engine transmissions will probably differ , cutlass bearings, shaft seals.

That said , you would have to decide whether resale value trumps owner satisfaction from nice repowering . In the case of my repower of gassers 11 years ago the total costs were substantially over the subsequent resale value but I knew I was keeping the boat and use benefits were far the greater priority. I might even do it again eventually.

Boats are a good investment ... in good times and boatyards.
 
Bob, resale is a concern only the I would like to get back 50% of the cost of repower. The problem is that we love the boat and want to keep it. So sometimes logic goes out the door. But I want to make good decisions,so the money would be spent wisely.
Sandy the shafts and drip-less seals are 3 years old so they should be fine. Transmission will be the same. the new engine is rated 330 hp VS the old at 300.

thanks for the reply
 
I would look into a rebuild I would expect it to be a fraction of the cost!

How many hours are on these motors?
 
$56,000 buys a lot of oil and degreaser. I'd change the oil before you leave to head back up to S.C., keep track of the running hours for the trip, keep a record of how much oil you add on the trip, use the same brand and type of oil to top off with as you used for the change and then do an oil analysis when you get back.
 
Have you had this boat for a long time? Has oil use changed? Diesel do use some oil . 5 qts isn't much depending on how much fuel you used. Are you sure that the props and bottom is not fouled? I would have a haul out and cleaning before the return trip. We need a lot of more info but many engines oil use rate slows once it gets down a bit. Dipstick calibration may not be correct for engine angle. How do you know you have blob by?
IMO you are very far from deciding if you need engines . Cummins remanufactured is what a good dealer would suggest.
 
Do both engines smoke equally?? How many hours? What rPM do you normally run?
 
low WOT and soot sure sound like overload from dirty bottom and props. Do both engines hit same rpm or is one weaker than the other?
 
quote:
Originally posted by Capt. Bill1

$56,000 buys a lot of oil and degreaser. I'd change the oil before you leave to head back up to S.C., keep track of the running hours for the trip, keep a record of how much oil you add on the trip, use the same brand and type of oil to top off with as you used for the change and then do an oil analysis when you get back.

Click to expand...


Beat me to it. Run it until it drops dead.

Now let me throw this at you. What about a reverse BillyIII repower. If you are doing a lot of hull speed cruising, a Carver 370 will do just fine on a set of SBC strokers or a set of BBC engines for a HELL of a lot less than $53K. Keep the diesel gennie.

I actually looked at a boat like this two years ago. I had never seen the setup before but it made perfect sense. It was owned by an older couple. They would cruise out to the Chessapeake at hull speed and spend a night or two on the hook with a few other boats for a night or two then come back in.
Propulsion fuel costs were maybe a hundred to one fifty and what ever a 5 kW diesel gennie burns per hour. They carried 200 gallons of gas and 100 gallons of diesel. Once I thought it through, it made a lot of sense.

The nice thing was the boat had ample power if necessary to suck a lot of fuel in an emergency and get them home at roughly 20 knots throttles pinned.

Just a thought.
 
IT AINT BROKE - DON'T FIX IT - CLEAN THE BOTTOM - OIL IS CHEAP, 5 QUARTS IS NOT EXCESSIVE - CLEAN THE HEAVY JUNK OUT OF THE BOAT - DON'T CARRY SO MUCH WATER - ONLY CARRY ENOUGH FUEL PLUS SAFETY MARGIN TO GET TO YOUR NEXT PORT.
 
I can't believe I'm asking this, but how many hours are on these engines? Wearing out a set of rings on a recreational boat is almost unheard of. Dropping a hundred rpm could be caused by a dirty bottom, dirty turbo blades, etc..

A diesel that is losing compression can be run right up until the day it just gets too hard to start on a cold day.

The good thing about an engine that has actually worn out a set of rings is that it likely is not dying from lack of use or over propping which is almost always the more typical case. Which also means the advice given May be different than typical. I really can't stress how rare of a situation this may be. Recreational engines die all the time and get repowered, but almost none of them were worn out. In your case, I might seriously consider the costs of re-ringing this engine. I'd really want to understand the mechanism for your current condition first though. Was this boat previously a charter? Is it's current use similar to its past use? All these things would have a material impact on deciding between rebuild and repowered. Most folks benefit from a repower as bolt ons typically are going to be ongoing costs and would limit reliability.

What's the access like in your engine room? Can engines easily be jacked up? Access to the pan or heads for boring? In the best of case you might be able to rebuild around 10k per side.

I was so curious I had to go look them up. Sounds like the 93 and prior period, cummins was still perfecting these engines in marine enviro. I'm not sure what the issue was, but the comment was that they would not tolerate being lugged. Specific examples were dropping a 100 rpm to 2700 and then the engines would not survive due to the lugging at the lowered rpm.

Your black soot and oil consumption could well be due to overloading and just be the effect, not the cause. Worth considering.
 
If you were in the st pete area I would know exactly who you should call. If you decide to make a side trip here I can set your up with someone who knows what he is doing on Cummins..
 
quote:
Originally posted by Sandy

Keep in mind the not-included installation costs can be very substantial plus that will also likely entail new prop shafts to deal with revealed wear/scoring and because engine & transmissions dimensions will probably differ ,plus cutlass bearings, shaft seals.

That said , you would have to decide whether resale value trumps owner satisfaction from nice repowering . In the case of my repower of gassers 11 years ago the total costs were substantially over the subsequent resale value but I knew I was keeping the boat and use benefits were far the greater priority. I might even do it again eventually.

Boats are a good investment ... in good times and boatyards.

Click to expand...
 
keep this thread going - interesting topic to me. I am on the fence to building up a pair of gas 540s OR finding some healthy take out diesels and just going for it. A friend has my 40-footer with Cat 3126s and he has thousands of trouble free hours on them....he also had thousands of hours on the previous pair of CAT 3116s so I know it is not a fluke....and he runs them very hard as he is an avid fisherman in Maryland so he has to run far to fish.
 
Thank you all for the responses.
The engines have about 1500 hours and it has been re propped by the previous owner to bring the RPM's up.
I think I am going to run it till it dies. We will not be able to run as hard as we did coming to Marathon but from what has been said we should make it home.
The starbord engine is the smoker. I may have a mechanic check the turbo, the port side turbo was just replaced.
Yes there is room to remove the pans with out jacking up the engines. I did not know you could rebuild.
The bottom has been cleaned every month so should be clean.
 
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