Engines, hours, and brands

[Mickeyrouse]

Dennis at Lakewood Yacht Service in Seabrook(Galveston Bay) told me he knew of shrimpers routinely using Perkins diesels for genset, refrigeration, etc. in excess of 25,000 hrs. We put about 8,000 hrs on ours. Smoked some, biggest problem was oil leaking from the rear seal. Re-powered due to major re-fit and desire for bigger engine. Went back with Westerbeke(Isuzu). Not a hint of engine problem after 12 years.

[SV WELDER]

Originally Posted by Mickeyrouse

Dennis at Lakewood Yacht Service in Seabrook(Galveston Bay) told me he knew of shrimpers routinely using Perkins diesels for genset, refrigeration, etc. in excess of 25,000 hrs. We put about 8,000 hrs on ours. Smoked some, biggest problem was oil leaking from the rear seal. Re-powered due to major re-fit and desire for bigger engine. Went back with Westerbeke(Isuzu). Not a hint of engine problem after 12 years.

Hmm, are all westerbekes a rebrand of another engine? I had read (when looking at a trawler years ago with a 75hp one) that they were not the most reliable brand but Isuzu seems to enjoy a good reputation so?

[SV WELDER]

Originally Posted by merrydolphin

I think that most marime diesels will go over 10,000 hours.
I have had incredible luck with the older Perkins engines. Sold on boat with a Perkins 4-154 with over 10K hrs on it. The buyer had a Perkins guy do an engine survey. Including oil analysis. He said that the engine show like an engine with 10K hrs, that there was nothing wrong with it and if it kept getting treated as it had, it would go 20K. On that note, my next boat had a Perkins 4-236, I sold it with almost 20K hrs, never missed a beat for me. New owner sailed it from Cabo to HI to Vancouver to Tahiti and back to Vancouver. All he did was an upper end rebuild (valves etc). Never a significant problem. I have no Idea how many hrs on it now. LOTS and still running well. Way over 20K. Yes, the old Perkins were leaky. I used lots of absorb pads. But nothing excessive. I know that many Yanmars to over 10K. It is important to use them and not baby them. They like to work. (With in reason). I always bring them up to full temperature and don’t run light loads too long. Good to go WOT sometimes for short periods (until you see temp start to rise). Change oil, maintain cooling, belts and hoses and not much else. Pulled my injectors on the 4-154 and brought them in to and injector shop in Trinidad just for preventative maintenance. That’s about it! These diesels are pretty amazing devices. Commercial trucks go 500K to a million miles.

Well, true about semi trucks however if you divide one million miles by average 40mph you get 25,000 hours. So, these tales of 20k hours plus, are still quite amazing!

[SV WELDER]

Originally Posted by Dsalvail

This may be one of the most useful questions asked on this forum for someone like me: I'm looking to upgrade my boat from a late-80's Hunter to a early 2000's Sun Odyssey, and I never know when the engine on a promising boat is circling the drain, based on clocked hours.
Maintenance logs are always welcome, but seldom available, so what do you do with limited information like "engine hours"?

An oil analysis is cheap and can be very instructive. They can tell you if various things are in trouble or need replaced soon or are past needing replaced and damage is occurring.

[SV WELDER]

Originally Posted by carstendenmark

OP, just a question - do you have a boat, or owned one before ?

Engines are only as good as they are maintained.

I flew a few ultralight aircrafts in South Korea in 2001.
They CHANGED their gas Bombardier engines every 200 hours (if the airplane survived that long), because they have read in the manual, that the crankshaft needs an overhaul after 200 hours. Any they didn't knew how to do that.

In the container/tanker shipping business, we calculate an average lifespan of a vessel to 25 years. Average hours a year = 8.000. Average RPM = 80%.

Correct maintenance is the key to a long engine life !

If you take over an engine, dont' believe anything of "hours" and "done maintenance", unless done by a professional at all times, proven by maintenance book stamps (which is impossible for a world cruiser).
If you don't know engines, let one who does check it for you.

If you are not a good sailor, then remember that the engine is your only lifeline.

I don’t have a boat but I have had several of various types, from go fast jet boats to lumbering dual diesel trawlers to baby outboards and all in between. Also have a diesel fetish on land and have done quite a bit of tinkering so I fully understand that hours are not the whole story by a long shot. I have engines with cylinders numbering 1,2,3,4,5,6,8,and 12. The best engine I’ve ever had the pleasure of owning is probably the Cummins 6bt, although the Ferrari v12 is certainly my personal favorite. But, baby diesels like found on sail boats is somewhat a unique application. It’s counter intuitive that a diesel will suffer shorter life if it is NOT throttled hard now and then (or even more often!) but it certainly does seem to be the case in many. It seems as though a lot of marine diesels are replaced at “end of life” by the hour meter (7500+/-) partly because the thought of a failure at sea is more inconvenient/dangerous than it would be on land, sort of like aircraft applications where failure is not an option. However with a cat specifically we can tolerate more risk of failure because we carry a backup in the other hull. So, we can then discuss such things as ultimate longevity where we might not choose to in a single screw type application.

[SV WELDER]

Why does it seem keel coolers are rare vs raw water pumping type setups? Seems like they would make big benefit in reliability by eliminating raw water impeller pumps which are known to harden, clog corrode and generally fail.

[Mickeyrouse]

Originally Posted by SV WELDER

Hmm, are all westerbekes a rebrand of another engine? I had read (when looking at a trawler years ago with a 75hp one) that they were not the most reliable brand but Isuzu seems to enjoy a good reputation so?

Westerbeke has never built any kind of engine. They have always marinized short blocks of general-purpose small diesel engines from conventional diesel manufacturers. Over the years they have thus adapted engines from VIRE, Perkins, Mitsubishi, Isuzu, and in their Universal line, Kubota, to name a few. Westerbeke is really a small company, whereas the short block manufacturers are large integrated companies employing thousands of people with manufacturing facilities.. To my knowledge, there are only a two or three purpose-built marine diesels- Yanmar and possibly still VIRE and maybe one or two more in Europe. I have had three Westy marinized engines in 30 years. The engines have all been robust and reliable. What Westerbeke adds to it- well, that’s another story. And the cost of parts is unbelievable- even for off-the-shelf items.

[donradcliffe]

There are a lot of Isuzu diesels in trucks around the world, so parts are pretty available. While I was looking at repowering for my leaky Perkins 4108, I ran into an Australian boat with a dead Isuzu engine in Cyrus. The timing belt had failed and wrecked the engine. I ended up with a Beta, which I liked because it was NOT a computer controlled common rail engine, but I sold that boat with only 2000 hours on that engine.

[Rotten Ricky]

As a trimaran owner, my long-shaft outboards were quite unreliable when the conditions were rough as they were either drowning under waves or screaming in the air. Your cat might not be affected so badly but it is still a matter to consider if conditions lift one stern out of the water - or close to it. They also provided very little charging ability and no heat. I also had to carry more fuel compared to diesel, or put another way, the same tanks, now with diesel will carry me much further, saving fuel.

But you cannot escape the laws of physics!

Remember when we tried to get increased power out of our cars when we were youngsters? The result was nearly always a less-reliable engine and a shorter life. Therefore if you get a slightly bigger engine, it will likely give you longer life and greater reliability. Just maintain it well. Never get the minimum size of engine that will barely do the job. The designers of sailboats in particular seem to have a blind spot about real world conditions, or they are penny-pinching to cut costs without regard for people lives. They seem to specify an engine on the vessel bringing it to hull speed on dead flat water, on a windless day and totally unladen.

The result is a small engine that is not suitable for life-threatening conditions. Having myself faced the desperation of bashing into head seas to escape dangerous conditions and another time having had to tow another boat with family on board away from rocks on a lee shore, I find comfort in having an engine that has a little extra grunt. It cost very little more, weights very little more, runs smoother with more cylinders, will last longer and is quieter. Because it can be happily run at a little less engine speed with a prop of greater pitch, it uses no more fuel that of the next size down. It is important that it has no turbo.

Also, do not use a transmission that is barely enough for the job, as it could overheat and fail early. It is mostly heat that kills a transmission.

I am a fan of the Kubota-based engines that are widely re-branded by other engine suppliers. There is a reason for that! However, be careful about the quality-control and added parts of the re-branding company. But Kubota are used all over the world in marine and industrial sites, from tractors to power generators to concrete mixers to boats, so parts are available world-wide at far less cost than any other - especially Yanmar and Volvo. A friend had his Yanmar transmission rebuilt - and it cost him more than the transmission of far greater capability for a Kubota - brand new, with warranty.

Note that manufacturers often demand as part of the warranty that the engine be propped to reach wide-open-throttle speed - somewhere around 3600 RPM - so they assume that the engine will normally be able to run at a comfortable speed, like mine at about 2,400. Again, there is a reason for that!

Best of luck,
Cheers, RR.

[Bill_Giles]

A diesel taxi in UK can easily achieve 250,000 miles. If that is averaged at 30mph it equates to about 8,000 hours. However our marine diesels are much less stressed with constant acceleration and deceleration.

[Dsalvail]

Thanks Firehoser75...
This information is immensely useful. For novice sailors, rigging, sailing, maintenance, etc. can be a lot to absorb, and the engine - you hope- is the one reliable thing you've got.
It's only when I became a little more experienced that the engine registered on the radar as one more thing to worry about.

Next in line is the transmission and shaft / sail drive...

Thanks again for your help!

[Wotname]

Originally Posted by SV WELDER

Why does it seem keel coolers are rare vs raw water pumping type setups? Seems like they would make big benefit in reliability by eliminating raw water impeller pumps which are known to harden, clog corrode and generally fail.

The main downside to keel cooling is they generally mean a dry exhaust. Dry exhausts are generally impracticable in sailing boats.

Not saying a dry exhaust can't be installed on a sailing boat.

[john manning]

My experience of small diesels which run at 2500rpm or higher is that they have about 7500 hours before a major overhaul is required. Marine diesels have a shorter life of 4000 - 5000 hours before overhaul.

Operating conditions are much more significant to engine life than any other factor. Short runs and long idle periods shorten engine life. ie. Just how yacht engines are used.

Installation is also significant factor. Diesel engines need a big air supply but this is seldom the case in yachts. Fuel filters should be as fine as possible. Oil sump drains should allow for removal of all the oil, not leave a litre behind.

Auxiliary equipment such as pumps, starters, alternators and fuel lines etc can have much shorter lives. Sometimes as little as 600 - 1000 hours.

[wingssail]

Originally Posted by SV WELDER

Why does it seem keel coolers are rare vs raw water pumping type setups? Seems like they would make big benefit in reliability by eliminating raw water impeller pumps which are known to harden, clog corrode and generally fail.

My objections to keel coolers are a) they are subject to damage. b) they cause drag. c) they require two more holes in the boat

[Morph]

To help answer your question around outboards on catamarans. My 40' cat had twin honda 20s--they were great! And I would have another set of 4 stroke outboards in a heartbeat. However it depends on the boat and the type of sailor you are. My boat was an extremely good sailing boat--daggerboards, 4-5 tonne, and designed to sail brilliantly in 3-4 knots of wind as well as sail off a lee shore in 35-40 knots of wind and 4-5m seas--(I know because I tested it out in a NSW East Coast low).



The only time we had issues with the props coming out was on a large beam sea--punching into a 35 knot southerly or being in a following sea was never a problem.


I loved the simplicity, no drag when sailing, no folding props and if there was a problem I could always lift them out via the boom and take them to the mechanic--which was never needed. The other consideration for me was weight and cost. They were about 1/3 of the weight and cost--so I could go through 3 sets in 30 years and still be at the same cost of diesels. They only got a basic service once a year (filters and oil change) however I think the big advantage was that I used them nearly every week, all year. The salt never really got to settle in the engine because it was used all the time.

We could cruise at around 5 knots with one engine using around 4 litres an hour-- no where near as good as a diesel of course. Top speed fully loaded was 9 knots with both engines, which was useful at times. The other thing was that, as it was a very good sailing boat, the engines were mostly used to just get off the mooring before we hauled up the sails so they barely warmed up--not so good for diesels...



So, yes poor charging and no hot water, but we got around that with gas and solar panels. For me I'd go for them every time, however I am aware it suits a particular type of cat and how it is used.


Phil