*THE HULL TRUTH is the world's largest FREE network for the discussion of Boating & Fishing. Whether you're researching a new boat, or are a seasoned Captain, you'll find The Hull Truth Boating & Fishing Message Forum contains a wealth of information from Boaters and Sportfishermen around the world.
Welcome to the updated THT!
If you are having trouble signing in, please email feedback@thehulltruth.com with your username and we will help you. We thank you for your patience as we help you access the new site!
Random Quote: If you haven't run aground, you haven't been around...
I am going to move to a twin diesel express after owning several outboard boats. The engines will be either new or lightly used (100 hours) CAT C7 or Cummins QSB5.9. I am asking in general terms the maintenance requirements for these engines (intervals, guesstimate of expense, etc). I haver talked to friends with diesels all of whom tell me the maintenance is not bad provided the engines are frequently run under load.
Also is an oil changer option worth getting?
Get the changer,makes oil changing a breeze. This is the most important maintenance on the engine, Period. I change mine every 150 hrs great insurance to keep them going. 32 Blackfi with 6000 hrs on 3208's
Take lube oil samples and get them checked. This will let you know any numbers of things like if your oil is still within useable spec @ the rate of change you are doing, fuel dilution-major important, TBN #, metal content in oil-bearings, etc., and a host of other items. Make sure to run a true diesel oil. They have the additive package to deal with diesel fuel.
Count on oil changes every 100 hours or at least once a season. Definitely get the oil exchange system. If you do not have access to the oil pan plug, you will end up pumping the oil out through the dipstick which usually leaves at least a quart of oil.
Change fuel filters and racors every season. If the engine is freshwater-cooled, change the coolant every other season and service the cooling system then as well.
Ballpark, you should budget about a grand a year for all maintenance for the engines. This may be a little more than you will actually spend, but it's better to overestimate.
If run on a regular basis, diesels are great. If not, they are a constant source of problems.
Oil changes are important but just one of the maintenance items. Talk to a mechanic regarding the scheduled maintenance items and the cost to perform that maintenance. You will want a certified mechanic to do the work so your warranty is maintained. Local support is very important.
I would suggest adding a fresh water flush system so you can flush the seawater side of the cooling system when you return from a day on the water. This prevents salt buildup in the coolers and coral growth.
I prefer Cummins over Cats. I have had Volvos for a long time and wish I could put Cummins in it.
Assuming twin diesels, $1,000/yr for maintenance as an average, even if you do it all yourself, is light. With C-7's, every oil change is 13 gallons plus filters - $300 (every 150 hrs or 1x year); every other year, raw water impellers - $125/each. Coolant, even every 5 years if you do ELC is $250; Every 4 years or 500 hours you will be cleaning aftercoolers and replacing them after 8-10 at $1,500 each. Add in hoses and belts every 5 years at $300 per engine. Then your Racors every 50 hrs - $30/set and on-engine filters every 100 hrs @ $35/set. Gear oil 1x season - $25/each. You get the idea. If you had a mechanic do your yearly maintenance, it is 1 day's labor - about $1,000-1,200 fro a CAT or Cummins tech depending upon where you are.
An oil changing system is almost a necessity with diesels because even the small ones hold a minimum of 5 gallons of oil per engine. I would not waste the money on adding the gears to the system as they only hold a gallon or two and are only done every 250 hrs or 1x year.
I concur on getting samples done everytime you change your fluids. I use Blackstone Labsn - found them to be better than the cat SOS program - more test parameters.
Absolutely, install an oil exchange system. It is also nice to have a separate portable system for pumping oil back into the engines. I am sure some may disagree, but the built in system can accumulate sediment that never completely pumps out. Using a "clean system" to add the fresh oil can prevent pumping the last dregs of oil and sediment back into your engines. The two services I have used always use the onboard system to remove the oil, and their own clean system to pump the new oil in. Again, the other posts are right on the money. Send off oil samples with every oil change. They could help you identify issues before they become failures.
I've had Caterpillar and Detroit diesels, Mercury, Honda, and Yamaha outboards. I spare myself the pain of actually tracking the maintenance costs, but I can tell you that the cost to maintain the diesels will pale in comparison to that of a set of outboards. The trade off is fantastic power, maneuverability, economy, and reliability. However, you really need to use the boat a bunch to truly justify the additional costs of proper diesel engine maintenance. One really nice thing about diesels...the smell alone will clear the dock of any loitering blow boaters!
Sorry, correction to last post, second paragraph, second sentence should read:"...the cost to maintain a set of outboards pales in comparison to that of maintaining a pair of diesels."
Thanks for the correction...I was getting confused. And I hope I'm not gonna derail this thread TOO much, but engine access always worries me with inboard boats. I had an old 32' Ocean with twin Crusaders that were stuffed half in the salon and half under the deck. I would have no idea how one would go about replacing them. The thought of a Strike or Sea Vee with twin diesels always gets me to salivating. But then when I look at where they squeeze them into, it worries me that a tech won't be able to service them. Are my worries unfounded?
And I hope I'm not gonna derail this thread TOO much
Guilty as charged.....
I will try to redeem myself, though. Engine access on an inboard less than 32 feet can be problematic. On my Carolina Classic, it was a problem getting access forward and to the outboard sides of the engines(Volvo KAMD 300). Putting a genset in the engine compartment adds to the constraints. Some boats are better than others in this regards....engine access on a Henriques 28 is great.
Back to the original issue of maintenance. Many good points have been made so far. I will stand behind my original esitmate on maintenance in my particular case. I run a boat with Cummins 6BTA5.9's, and a thousand bucks keeps me in filters, oil, etc. with plenty left over for beer. Bear in mind, parts for these engines are plentiful and cheap--and I do all the PM myself. New engines still under warranty are different beasts...as far as PM goes, you can still do that yourself, but all service work must be done by certified technicians--and that adds up quickly.
Also, it goes without saying that have the engines surveyed before you buy.
Very good points about the engine access. My caterpillars were in an express with what could be considered good engine access by express standards. Still, Caterpillar service only had two technicians nimble enough to service the boat. Inboard and topside engine access was good, but front end, back end, and outboard engine access was problematic. The guys had to either lay on top of the engines, or contort themselves into adjoining bilge areas, just to service the marine gears and cooling bundles or replace/tighten belts. Access may not be the initial topic of the thread, but is is a very important point.
I've been stung on engine surveys before. Two independent engine surveyors would be my recommendation. Make sure the broker or seller doesn't know either one of them!
I concur with all that suggest an Oil Xchange system. If not so equipped, get one added ASAP. When wondering about service, instead of relying on dock talk and heresay, talk to a Certified Service Center that is warranty certified for the brand you are considering. They will give you the manufactirer's suggested service intervals and what is required at those intervals based upon your specific usage. While you may choose to do your servicing more often, at least you can rest assured that you are, at a minimum, within the maker's specifications.
While oil samples are ok, they can only be totally accurate if there is a base line to compare to. If the boat you are considering has just had an oil change, with no or very few hours since, and no previous oil samples to compare to, the information thay can provide will be limited. In some cases, with fresh oil that has only has sngle digit hours running time, is nearly useless. Even if taken after a the sea-trial, there may not be enough contaminates or particulate matter in the sample taken to raise any alarms.
Now, before I get blasted, an oil sample can give indications of some very serious conditions that may exist in the internals..... Such as coolant in the oil, metallic particulates and what type of metal. Some metal paticulate matter is not abnormal, but is you are getting above limit readings of copper particulate matter, that is a red flag that the clevite style bearings may be about shot, meaning a MOH is on the near horizon.
ANY smaller inboard powered convertible will have limited access to the engine room and you will either have to be a contortionist or have one as your tech to get around in there. Express style boats can and are usually easier since they have deck lift systems that can ease that access.
My first recommendation, is to get a broker that will represent you as the buyer. One that is not beholdin' to the seller in any way. He/She will be acting on your behalf and their fiduciary duties belong to only you, as the buyer. This service is provided by many repiutable brokers and is strongly suggested on any big dollar transaction. THese brokers will have a network of diesel surveyors, hull surveyors and know who to use and (more importantly) who NOT to use in the area where the vessel is located. Best thing, in the vast majority of cases, there is absolutely NO cost to you as the buyer. You wouldn't go to divorce court using your spouce's attorney, would you?
Oil change system a must, on the cummins the raw side of the cooling system is the weak spot so I would definately install a fresh water flush system. I do agree with running the boat frequently makes it easier to maintain, that holds true for gas or diesel. With the oil change system you can easily change your own oil saving substantial $$. One more item I would spring for are wolverine oil pan heaters which greatly reduce start up smoke. (Inexpensive)
I use the bucket with a pump on top to change the oil and it works great except the time I accidentally flipped the switch and sprayed my brother in law with hot oil on his balls and well the couple times it fell over in the trunk of the old Mercedes cause their so darn top heavy evacuating whatever oils left in them but all in all not bad.
__________________ 2001 Pursuit 3400
370 HP Vulvo tamd 63 pa's
I believe that the Cummins QSB 5.9 is basically the same engine as the Iveco 370hp's that I run in my boat (from a joint venture type arrangement between Cummins & Iveco). If they are, from memory my recomended oil changes are at 600hrs, impellors at 1200hrs, fuel filters at 200 or 300hrs (can't quite remember). I think that the anodes are at 600hrs but would need to check. I do around 1000hrs per annum when busy and after doing oil samples etc for the first couple of years to check the effect of these longer change periods I now do my oil and filters at 500hrs to be safe (although the oil tested Ok at 600hrs), run a Racor in front of the primary fuel filter that I change every 100 - 150hrs (cheap 5 minute job), do my primary and secondary fuel filters every 300 hrs, anodes with the oil change at 500hrs. I do the impellors at 500 - 600hrs as the 1200hrs initially listed is far too much and an error I believe.
I am not sure that the Cummins is the same, and I do many of my hours at 1300RPM trolling, but many of these larger common rail engines with decent oil capacities are certainly more like one service per year for even a moderately busy recreational owner. One thing with common rail though, is that you can not be too careful with your fuel. This is why I run a Racor glass bowl filter/seperator in front of the proprietry 'can style' filter/seperator. Easy visual check for water, plus easier to drain if you need to in a situation where you might get 'watered' fuel.
I do not have an oil change system on my boat and its not really a problem for me. I have a 12 volt oil pump I got from Grainger and made up a couple of hoses. My Detroit Diesels have a separate dip stick for oil changes. I just slide the suction hose over the dipstick tube and the discharge into a 5 gallon pail. All the oil is pumped out in about 5 min. The total cost for an oil change is about 400 dollars. I put anywhere from 100 to 150 hours a season. I usually change the oil and filters (includes fuel filters) in the fall and then again around the end of July. I believe Detroit calls for changes every 250 hours, but since my engines were just overhauled I like to do frequent changes to get any "break in " metals out. I do pencil zincs in the fall before lay up, and water pump impellers in the spring. Transmission oil gets changed every other fall along with their filters and the screens get cleaned at this time. As for coolant It was just changed out last winter and I keep track of the ph and additives with coolant tester strips. If the engines in the boat you are buying have wet liners or you are buying Yanmars you must keep up with freshwater (antifreeze) side of these engines. Good Luck!!
Man, that is a lot of great information. As to those who queried I am just about set on a Cabo 32 express with Cummins. From what I have seen on a number of boats the engine access seems good for this type and size of boat. I have had the Cabo vs others argument a lot so no need to go there. I think it will fit my needs nicely. I will certainly get a survey on the boat and engines before buying. Thanks to all who responded and I would welcome any more info. The boats I am looking at all have an oil change system on them.
Question for inboard owners-deisel 
