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Old 12-01-2016, 20:40   #46
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Re: Boats with Re-built motors...What to Think?

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Originally Posted by terabika View Post
So it is not the idling which hurts a motor; it is the idling only of a diesel motor. As long as people work their motor on occasion all is good. I would think the bigger sin is to not let them run warm long enough to evaporate the condensed water inside the crankcase.
A friend of a friend (both fishing trawler skippers) slipped off the dock side while tying up, and fell onto the deck of his boat doing himself a nasty that put him in hospital for 3 weeks.

When he was let out, the first thing he did was go and see if his boat was ok. It was, and the Gardner engine was still ticking over happily like it had for the past 3 weeks. He was worried it must have been close to running out of fuel, so checked the tank, and was amazed how little fuel it had used in 3 weeks.

After that, he never turned the engine off, except for oil changes.

Reliability improved and fuel economy had a dramatic improvement. He had the impression it was running a lot smoother too. The way it 'talked to him' had changed.

Whether petrol or diesel, I am absolutely amazed that anybody can possibly think that stop start driving does anything but harm.

They obviously haven't asked any engineers about it, and haven't even considered that there may be substantial downsides that dramatically increase the things they are trying to cut (like the vast increases in prematurely failed parts having to be made and shipped all over the World).

There doesn't seem to be much in the way of joined up thinking going on these days.
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Old 12-01-2016, 21:05   #47
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Re: Boats with Re-built motors...What to Think?

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A friend of a friend (both fishing trawler skippers) slipped off the dock side while tying up, and fell onto the deck of his boat doing himself a nasty that put him in hospital for 3 weeks.

When he was let out, the first thing he did was go and see if his boat was ok. It was, and the Gardner engine was still ticking over happily like it had for the past 3 weeks. He was worried it must have been close to running out of fuel, so checked the tank, and was amazed how little fuel it had used in 3 weeks.

After that, he never turned the engine off, except for oil changes.

Reliability improved and fuel economy had a dramatic improvement. He had the impression it was running a lot smoother too. The way it 'talked to him' had changed.

Whether petrol or diesel, I am absolutely amazed that anybody can possibly think that stop start driving does anything but harm.

They obviously haven't asked any engineers about it, and haven't even considered that there may be substantial downsides that dramatically increase the things they are trying to cut (like the vast increases in prematurely failed parts having to be made and shipped all over the World).

There doesn't seem to be much in the way of joined up thinking going on these days.

Bloody good yarn.....a Gardiner (closest thing to perfection ever) ,being such a stroker with very low BMEP (brake mean effective pressure) and low volumetric efficiency has very low piston speeds. Not only that but with a very tall piston there is almost no piston flop as it goes over top dead centre and so the rings will always seal well, irrespective of throttle valve opening. On an old stroker varnishing is not a problem but on modern hi speed diesels prolonged low loads lead to bore varnishing.

And your theory of stop start wear is spot on. Almost all wear takes place on start-up because oil has drained away from piston rings and bearings etc and so until there is plenty of oil splashing out of the conrod hole onto the cylinder wall the piston and ring assembly are running virtually dry.

Petrol engines, especially with carburettors and chokes, wash their bores dry of oil until until well after fire-up has begun. By then the damage is done.

But again, modern diesels need to be run hot and loaded else usually a high price will need to be paid.

Good post of yours imho.
And I beleive ALL Gardiners talk to their skippers.
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Old 13-01-2016, 06:38   #48
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Re: Boats with Re-built motors...What to Think?

Well I have just sent an enquiry off to a very interesting looking diesel engine manufacturer in China (3 cylinder FWC 25hp diesel, long stroke, but they do others), and looking at the numbers, the waste material really is about to hit the fan with engine prices in general.

If they can configure one marinised how I want, as a test bed, I'll shove one into a boat, and live with it for a year with plenty of use. If it passes with flying colours, I'll import them.

I'm also asking if they can supply with suitable transmissions.

I tell you this though, the pricing asks some very serious questions about the pricing policies of other engine manufacturers.

PS. Anybody have 'hands on' with what the most suitable stainless steel is, for engine bolts and other engine fixings and fittings? Frequently 'usually recommended' isn't the best (have had to put some people right with some non-marine applications, due to 'what people usually use' being not that good, and even a bad idea). Stainless bolts aren't expensive (little if any difference to other materials wholesale - I have bought them wholesale direct from manufacturers), and are used as after market replacements for motorbike engines, for example. Is stainless suitable for injector pump and fuel tubing?

PPS If this pans out, I will declare exactly what they cost me (this will shock you), what the shipping and duties cost me, and what my margin is. If I get volume discounts at the end of the year (usual practice which nobody talks about) then all purchasers that year will get a rebate on their purchase price, and will not be pocketed. I've done similar to this before (successfully), for example passing on significant savings from substantial profits from dealing with the associated FX market.
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Old 13-01-2016, 07:53   #49
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Re: Boats with Re-built motors...What to Think?

Thirty, forty or so years ago pre-oilers were all the rage, theory being establish oil pressure and flow before the engine even turned over and they would last nearly forever, since as everyone knows most wear occurs right at start up, right?
Well guess what, pre-oilers fell out of favor, why? Because they weren't significantly increasing engine life span. Why? Who knows for sure, I don't but apparently, maybe most engine wear doesn't occur at start up, or maybe pre-oiling doesn't prevent this wear?

What cinched it for me was this Prius thing I drive, every time you lift throttle, the engine shuts off, I now have over 165,000 miles on the thing and still no significant blow-by, and this thing has God knows how many re-starts, maybe millions for all I know. Now I admit shutting off and re-starting 10 times in 30 minutes are not real, honest cold starts, but I'm beginning to maybe not believe some of the truisms that I took for granted growing up. For instance if city driving, the engine never gets fully warmed up, it's off most of the time.

With truck motors idling, it is true that they have done that well, forever and seemingly without harm, but almost always after that extended idle comes a long stint of extended high power operation as the truck hits the road, where a boat motor that is used to charge batteries does not get this high power stint, it gets shut down.
Maybe it's cranking it up everyday and running it for a few hours, never getting it hot that causes the damage?


Little boat Diesels are about as simple a motor as exists, anyone with a little mechanical ability and attention to detail can overhaul one successfully.

I'd tell you that almost all motors I have overhauled were better than a new factory motor, because I often use better than factory parts, and hold my tolerances tighter than the factory does, there really is such a thing as a "blue-printed" motor, it is a concept that has been around for a loooong time.

But then I have also been known to pack my family into a single engine airplane who's motor I overhauled and fly to San Salvador Bahamas, and up to Tuktoyoktuk Canada too, and I am sure that motor was better than a factory new, zero time engine.
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Old 13-01-2016, 08:24   #50
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Re: Boats with Re-built motors...What to Think?

Anything used is a gamble.. In fact rebuilt at least indicates someone did some work.. These are low power things that shd run for a long time with proper care..

I'd take the chance if the boat looks good.. You are better off watching some vids on how engines work and start your career in gaining knowledge about motors.. Ud be much better off anyway lol..

My friend sailed from Seattle to LA, after a day engine cut out.. He paid dollar for a mechanic to come out.. All it took was a simple fuel system bleed.. Now he does it himself..

Knowledge is power they say, well on the ocean it's even more true..

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Old 13-01-2016, 11:29   #51
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Re: Boats with Re-built motors...What to Think?

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HUmmm so how many are a lot of hours on these little diesels I looked at one that had 3,300 on it I somehow equated that to 150,000 to200,000 miles on the road, with a road motor it's just getting broke in if it were maintained properly.
So if maintained the way it should be and nothing stupid happens what do Y'all get out of them.
We run three Perkins diesels on our tug as generators. They are essentially the Prima sailboat engine. The primary has more than 26 000 hours the next in line has more than 15 000. During inspection for international class last spring neither required work.
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Old 13-01-2016, 11:46   #52
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Re: Boats with Re-built motors...What to Think?

4000 hours on a diesel is more like 10,000 miles on a car. Should get 50,000 hours easily for a good diesel engine with regular care. 150,000 hours not unheard of for diesels before they have to be rebuilt. The older, low rpm engines really did not have a "lifetime" limit and many built at the beginning of the last century are still good to go. Low wax fuels may change that reality in the future with regards to injectors and seals, but those are simple to repair.
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Old 14-01-2016, 11:54   #53
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Re: Boats with Re-built motors...What to Think?

A rebuilt motor is a crap shoot. How thorough a rebuild process is totally depends on the shop or individual. I used to build high performance automotive engines and know the failure rate of major parts. Was the head totally rebuilt? Maybe, maybe not. Was the crankshaft magnafluxed? Probably not.
I prefered seasoned blocks because they were already stress relieved but you had to inspect quite a few to find good ones. Same with cranks, you'd be surprised how many looked perfect until properly inspected, then the stress risers and micro cracks would show up.
However, if your used motor happens to have been taken care of well and didn't have any significant issues from the original factory it might be a good candidate for a rebuild. Problem is, you have to have it done by a reputable builder/ shop and get a warranty from them.
I'd rebuild my own but have 1000s of hours of experience and don't trust too many rebuild shops I've seen. Unless you have this level of experience or know of a really good rebuild your better off going new. If the seller claims "rebuilt" make sure to have them produce all the documentation and the contact info of the rebuild shop.

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Old 14-01-2016, 12:06   #54
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Re: Boats with Re-built motors...What to Think?

It seems many boats are advertised with "rebuilt motors". When pinned down the sellers often say, "well, it was rebuilt by the guy who sold it to the guy I bought it from" If the seller has receipts, get them. Otherwise, no rebuild.
Sometimes seller's seem to think just removing a head and replacing a head gasket is a "rebuild" too.
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Old 14-01-2016, 15:01   #55
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Re: Boats with Re-built motors...What to Think?

Reconditioned = good deal.
Rebuilt= very questionable.
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Old 27-06-2016, 20:50   #56
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Re: Boats with Re-built motors...What to Think?

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Is it wasn't a BCC it was 24 foot derivative of one named SERRAFYN.
Let me guess.... you aren't going to tell the forum exactly what the boat was right.
Nor are you going to give us details about Taleisin .....or are you Stu.
If you do tell us will you include the part where a removable outboard was on Taleisins manifest.....plleeeease ?
I realise this might be a little late to the party...

I'd like to know more about this removable outboard, seeing as how we own Taleisin and I can assure you she was designed and built to hate outboard motors. I've been scratching my head for over a year now to figure out how I can mount an outboard on her to get me in and out of the marina.

The outboard you're referring to is a 2.5 hp short shaft honda that fits the dinghy. While it's possible to hip tow Taleisin with this dinghy I can assure you it requires quite a bit of skill (more that I possess at the very least).

She loves living on a mooring and sailing on and off the mooring while adventurous is quite doable.

I hope this clears up any misconceptions as to the state of the motor in/on Taleisin.

For the record, I've figured out how to mount training wheels (outboard), and for those who care it won't harm Taleisin in any way, it will be removable without a trace and hopefully not too horrible to look at.
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Old 27-06-2016, 21:29   #57
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Re: Boats with Re-built motors...What to Think?

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Originally Posted by a64pilot View Post
Thirty, forty or so years ago pre-oilers were all the rage, theory being establish oil pressure and flow before the engine even turned over and they would last nearly forever, since as everyone knows most wear occurs right at start up, right?
Well guess what, pre-oilers fell out of favor, why? Because they weren't significantly increasing engine life span. Why? Who knows for sure, I don't but apparently, maybe most engine wear doesn't occur at start up, or maybe pre-oiling doesn't prevent this wear?

What cinched it for me was this Prius thing I drive, every time you lift throttle, the engine shuts off, I now have over 165,000 miles on the thing and still no significant blow-by, and this thing has God knows how many re-starts, maybe millions for all I know. Now I admit shutting off and re-starting 10 times in 30 minutes are not real, honest cold starts, but I'm beginning to maybe not believe some of the truisms that I took for granted growing up. For instance if city driving, the engine never gets fully warmed up, it's off most of the time.

With truck motors idling, it is true that they have done that well, forever and seemingly without harm, but almost always after that extended idle comes a long stint of extended high power operation as the truck hits the road, where a boat motor that is used to charge batteries does not get this high power stint, it gets shut down.
Maybe it's cranking it up everyday and running it for a few hours, never getting it hot that causes the damage?


Little boat Diesels are about as simple a motor as exists, anyone with a little mechanical ability and attention to detail can overhaul one successfully.

I'd tell you that almost all motors I have overhauled were better than a new factory motor, because I often use better than factory parts, and hold my tolerances tighter than the factory does, there really is such a thing as a "blue-printed" motor, it is a concept that has been around for a loooong time.

But then I have also been known to pack my family into a single engine airplane who's motor I overhauled and fly to San Salvador Bahamas, and up to Tuktoyoktuk Canada too, and I am sure that motor was better than a factory new, zero time engine.
Years ago most oils were purely mineral based, as such their surface strength was marginal, then with use was reduced to almost nothing. Even the least expensive modern oils have some synthetic component. This makes for a much better film strength, wich is all important during start up for parts like camshafts and lifters, to keep them from grinding each other to dust until an oil wedge can form.
Many other factors come into play such as clearnce tolerances and expansion rates in an engine as it begins to warm up and different parts expand at different rates, the number of reasons for advanced wear during warm up are too numerous to list in a simple way. Suffice it to say that modern lubricants are light years removed from the crap I used to use in my old British motorcycles, that is the main reason you see such improvements in the lifespan of ancient engine designs. The marriage of better lubricants and modern metallurgy and design in modern engines has pushed operating spans even further.

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Old 27-06-2016, 22:23   #58
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Re: Boats with Re-built motors...What to Think?

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. Suffice it to say that modern lubricants are light years removed from the crap I used to use in my old British motorcycles, that is the main reason you see such improvements in the lifespan of ancient engine designs. The marriage of better lubricants and modern metallurgy and design in modern engines has pushed operating spans even further.
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Well the very best aircraft piston engine you can get to this day, new or overhauled, requires that you use that old "crap" for a good while or it will never break in. Some sort of modern whiz bang water cooled car engine built by a computer is not a boat motor or an airplane engine or an old motorcycle so it's apples and oranges.
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Old 27-06-2016, 23:32   #59
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Re: Boats with Re-built motors...What to Think?

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I've had to sell my Ericson 27 (See the link to see some sailing of it: https://www.youtube.com/user/billybobhack). Yet, I keep my eye on sailboatlistings.com, yacthworld.com, and CL. I bought my Ericson because it had a new motor with only 186 hours on it. People told me I could make more money than I paid for the boat just selling the motor. I didn't of course.

So my question is, as I imagine owning another sailboat, "What to think of rebuilt motors in a boat?"
My advice is to forget about making money on a boat, and focus on getting a good one and then sailing it.
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Old 29-06-2016, 08:56   #60
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Re: Boats with Re-built motors...What to Think?

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Well the very best aircraft piston engine you can get to this day, new or overhauled, requires that you use that old "crap" for a good while or it will never break in. Some sort of modern whiz bang water cooled car engine built by a computer is not a boat motor or an airplane engine or an old motorcycle so it's apples and oranges.
Not really.
Modern synthetic lubricants are so good that you actually need old basic oil for break in, mainly because the film strength is sooo good the "rough" machined parts never get to "meet" each other, some companies even sell "break in oil", which usually means old crappy mineral based oil from dead dino's, and they charge extra! So on synthetic oils the machined surfaces never actually wear or break in, good for camshafts, not so good for rings and cylinder sealing. Once over the break in period moving to a modern multi-viscosity oil is recommended by the majority of engine manufacturers, for good reason.
Most new marine diesels these days have also benefited from modern metallurgy and and design to minimize parts mismatch when it comes to tolerances, expansion rates and stress in critical areas. That's why you see them getting lighter while also producing similar torque and lasting just as long when properly maintained.
My reference to old motorcycles did have a parallel in that most of them were designed in the 1930's and were used right up until the 1970's when competition forced them to modernize, think Harley Davidson and the British manufaturers. Most of the common recreational boat diesels were designed in the same era as commercial small tractor, truck, bus and utility diesels and their design did not change much until more modern designs either forced them out of the market or forced their companies to modernize the design. Most were tractor or lorrie diesels marinized for boat use.
Even so, they also benefit from the lubricity of modern oil. Even the cheapest multi-viscosity oils are half synthetic, half mineral based and are light years ahead of the crap I used to use years ago.
I once ran a motorcycle repair shop with a good friend of mine, when I switched to using synthetic oils in the 1970's from the old mostly mineral based oils the difference in engine wear was amazing, not just a slight imrprovement, a day and night difference. They could go longer between changes, sludge and carbon accumulation was reduced to almost zero and the real reason for changing it was to get rid of the contaminants, not because the oil was no longer able to lubricate.
My old 4-108 runs forever because it's built heavily and is a comparatively low RPM engine, this coupled with the long life and extreme film strength of modern lubricants makes them last even longer when maintained properly.
No matter what the application, lubricating oil faces similar challenges whether it's a diesel or gas engine, in fact gasoline engines, especially modern high revving, extremely compact ones are much harder on lubricants than my old low speed lugger. The nastiness of combustion byproducts in gasoline engines is a huge contributing factor, the fact that they basically scrub their cylinder walls clean on every combustion cycle, the high RPM (crankshaft loads are not linear, they pretty much square with RPM) put much higher demands on the oil.
Most old diesels don't come close in the amount they torture their lubricants, the biggest issue I've seen over the years is either an owner who doesn't change it often enough, or at all, or the owner who doesn't bother to check it and runs out. Or the diesel that just rusts into a pile of junk from lack of care. Hey, when's the last time you adjusted the valves in your old 4-108? I've asked a number of other owners of my engine model and to a one they looked at me in total confusion, which usually means never. Thank goodness they used modern lubricants.
Dang if you just change the oil once in awhile and check it regularly your engine should last a good long time. Maybe a spot of paint once in awhile if you see a rusty spot. My 4-108, like any old British motor doesn't rust, it leaks enough oil on itself that it is protected from moisture by default, that also forces me to maintain it on a regular basis since I have to change mats in the catch pan on a regular basis and check the oil level, and maybe give it a good wipe. I'll be pulling it out soon, not because it needs a rebuild, most because it needs new gaskets and seals, but what the heck, why not rebuild it while I'm at it.
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