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Old 23-02-2016, 18:34   #31
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Re: Why switch to a new engine

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Originally Posted by ceder View Post
As an owner of a thirty year old Yanmar 2GM20 which has been fresh water cooled since new (or close to it anyway). It works fine, it starts easy, it does not smoke, it has lots of power etc. Still its like I feel that I must soon be ready to upgrade to a modern engine.

However, when one come to think about it it seems highly unlikely that, if maintained, the engine will suddenly fail. I am guessing that if anything either of the water pumps will fail letting the engine to overheat. That should however not be a big issue if the engine is shut down soon enough. The only clear risk I see is that the mixing elbow could fail, letting water into the ports risking corrosion or compression damage such as bent conrods, cracked cyl head, destroyed piston rings etc. But other than that I would guess that the wear will be evident by lack of compression, that it will be harder to start, start to smoke, consume more oil or similar. But this is seldom something that happens over night and it will not suddenly render the engine useless.

However, it would be very interesting to hear if anyone has actually upgraded their engine due to an actual break down which was not related to negligence when it comes to maintenance.
===

Nothing in your post indicates to me that you need a new engine. As you said, it starts easily, runs well and does not smoke. Presumably it is not using oil. Those are all signs of a healthy engine that has many more hours left in it.

What I'd recommend is reading your service manual and/or talking to an experienced Yanmar mechanic. Presumably you are already getting your raw water pump serviced regularly. If not, that's the first place to start. Replace it before the shaft seals fail. Replacing the exhaust elbow is a fairly easy job and is another item that requires periodic service/replacement - same with the injectors. You can always keep the old ones as emergency spares. Getting the valves adjusted is another item that needs to be done every 2,000 hours or so. At about 4,000 hours consider replacing the fresh water pump because the shaft seals/bearings will eventually fail. Those engines can go 10,000 hours with good maintenance and no over heats. Doing the periodic parts replacement and maintenance is much cheaper than getting a new engine, and it will improve your overall reliability. Carry a spare raw water impeller, filters, extra belts, and maybe a spare alternator.
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Old 24-02-2016, 10:42   #32
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Re: Why switch to a new engine

Quote:
Originally Posted by ceder View Post
As an owner of a thirty year old Yanmar 2GM20 which has been fresh water cooled since new (or close to it anyway). It works fine, it starts easy, it does not smoke, it has lots of power etc. Still its like I feel that I must soon be ready to upgrade to a modern engine.

However, when one come to think about it it seems highly unlikely that, if maintained, the engine will suddenly fail. I am guessing that if anything either of the water pumps will fail letting the engine to overheat. That should however not be a big issue if the engine is shut down soon enough. The only clear risk I see is that the mixing elbow could fail, letting water into the ports risking corrosion or compression damage such as bent conrods, cracked cyl head, destroyed piston rings etc. But other than that I would guess that the wear will be evident by lack of compression, that it will be harder to start, start to smoke, consume more oil or similar. But this is seldom something that happens over night and it will not suddenly render the engine useless.

However, it would be very interesting to hear if anyone has actually upgraded their engine due to an actual break down which was not related to negligence when it comes to maintenance.
Well, if it is in good shape with low hours, I am looking for a 2GM20 to 3GM30 to replace my 40 year old Farymann RM30 that has 1200 hours on it.

If it weren't for that parts are getting hard to find, (Farymann is all but out of the marine diesel business) I would leave it in for at least another 40.

Regular maintenance items include:

1. Replace freshwater pump impeller every 4 years*.
2. Oil and filter change every year, or 100 hours, which ever is less*.
3. Drain water separator regularly (check weekly to start, until history dictates schedule.)
4. Replace water separator filter, every second oil change*.
4. Replace fuel filter every second oil change*.
5. Replace exhaust elbow every 4 years*.
6. Motor mounts every 5 years*.
7. Check and adjust valves every 100 hours*.
8. Check oil and transmission fluid before every start-up.

* or right now if you don't have accurate maintenance records.

Low cost maintenance prevents high cost engine replacement and inconvenient or catastrophic failure at the worst possible time.

RamblinRod
Marine Service Provider
About Sheen Marine
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Old 24-02-2016, 11:47   #33
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Re: Why switch to a new engine

buy spares and re build when you see need. is not in need now.. have fun sailing.

my yanmar in my ericson was 2qm20h awesome lil machine.
i am cruising formosa with perkins. when i bought it it had westerfreke, see ka lunk, name of thread....
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Old 24-02-2016, 12:25   #34
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Re: Why switch to a new engine

We replaced our 1976 2 cylinder 21 HP Ferryman instead of rebuilding when we were seeing blow by. Our primary reason for doing so was because parts were very difficult to come by, and were extremely expensive. They were routed to New Jersey from Germany, trucked to the west coast, and barged to SE Alaska. Shipping was several times the cost of parts that were expensive to begin with, and when repairs required parts we hadn't laid in spares for, it significantly impacted our sailing season. A secondary reason was because we wanted more power to better handle our strong currents. If the expense and availability of parts wasn't an issue, we probably would have opted to rebuild.
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Old 24-02-2016, 12:47   #35
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Re: Why switch to a new engine

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Originally Posted by moseriw View Post
PS Treat turbo's right, and they shouldn't fail for a very long time.

Friend of mine is servicing a pilot boat with 2 years old 2x 850 Hp turbocharged engines. One turbo was done after 14 month.

That's the classic lifespan of an abused turbo that's been spun up before there's any oil feed reaching it, and switched off (cutting off the oil supply) before it has been spun down.

A neighbour had a Saab 900 Turbo, and he was getting fed up with changing turbo's in that time period.

I told him how to treat them, and he never destroyed another turbo after.

You can't blame hardware for user malfunction.

PS Good advice RamblinRod.

PPS What zeehag said too. Acquire the rebuild parts before you need them (other than pistons and rings, as you may need to go oversize, but you can bore and use liners to keep original sizes). An engine that is obviously 'tired' but still running, can be a lot cheaper to rebuild than one pushed too far.

Something to be aware of too. When Mobil 1 fully synthetic first came out, a diesel lorry fleet was split up into normal lube for oil changes, and others using Mobil 1 for oil changes (may not have even been oil changes, may have just changed filters and topped up - I can't remember which now).

Anyway after 100,000 miles the motors were stripped down and tolerances compared. The normal lube lorries had normal wear and tear. The Mobil 1 lorries had no measurable wear and tear.

Guess which oil I'll be using in mine? The same one I used in my little Yanmar generator - Mobil 1.
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Old 24-02-2016, 13:04   #36
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Re: Why switch to a new engine

You treat a turbo motor the same as you should treat any motor.
All motors should be properly warmed up prior to being put under load, and all motors should be allowed to cool down prior to shutdown.
But a Turbo is a little less tolerant, it's not just oil flow, unless your turbo has a water cooled center section a major cause of turbo failure is the oil in the center section coking after shut down in an engine that was not idled long enough for the exhaust temps to drop. Heat in the exhaust side of the turbo will cook the oil after shutdown forming coke, this coke will both block oil flow and it's abrasive and eats out the center section bearing, bearing worn and the compressor or turbine side makes contact with the housing and the turbo is "blown".
I'd idle one for four or five minutes myself, which almost everyone does anyway, and in my opinion a benefit if a pure synthetic oil is high temp tolerance and it's insurance for a turbo motor.
I've run turbo Diesels for years and never blown a Turbo, but I almost always have a pyrometer and idle to exhaust temp drops to below 300 too.
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