Why switch to a new engine

[ceder]

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.

[ceder]

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.

[Paul L]

Why not swap out the water pumps and mixing elbow now. Save the old ones as backups and enjoy another 1,000 hours on the engine? You haven' t mention any signs of the engine misbehaving.

[ceder]

Originally Posted by Paul L

Why not swap out the water pumps and mixing elbow now. Save the old ones as backups and enjoy another 1,000 hours on the engine? You haven' t mention any signs of the engine misbehaving.

No that's my point. The engine is behaving just fine, the mixing elbow is intact and will for sure work this season as well. But it's as if the general opinion is that the 30-year old engine has to go. But honestly, why?

How would it fail on me?

I have yet to find anyone that can honestly tell me their engine failed and that's why the installed a new one. (Other than due to water in the cylinders, and that should be possible to avoid)

Still it would be very interesting to hear from anyone that switched due to a breakdown and what the error was and what lead to the breakdown.

[Paul L]

Originally Posted by ceder

No that's my point. The engine is behaving just fine, the mixing elbow is intact and will for sure work this season as well. But it's as if the general opinion is that the 30-year old engine has to go. But honestly, why?

How would it fail on me?

I have yet to find anyone that can honestly tell me their engine failed and that's why the installed a new one. (Other than due to water in the cylinders, and that should be possible to avoid)

Still it would be very interesting to hear from anyone that switched due to a breakdown and what the error was and what lead to the breakdown.

Lots of people switch engines after a breakdown. In many cases it is after repeatably fixing relatively minor items that starts to feel like death by a thousand paper cuts. If you add up the costs of items like mixing elbows, saltwater and freshwater pumps, heat exchangers, injectors and valve jobs, it doesn't take long to get to 75% of the price of new engine.

[sailorboy1]

Originally Posted by ceder

. But it's as if the general opinion is that the 30-year old engine has to go. But honestly, why?

I think that the only ones who have that "general opinion" are people looking to sell you a new engine.

I don't think you can predict things that will suddenly kill an engine. Other than a massive overheat or a broken mount that causes the crankshaft to break I think engines die kind of slow.

The question is whether there are still parts available for your engine and whether you should get some common ones now.

[barnakiel]

Originally Posted by ceder

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.

(...)

Why replace something that works OK?

I would do nothing until the engine is kaput. If you are in a sailing boat.

I could consider an 'early' replacement, if it were a power boat.

b.

[Hudson Force]

I didn't see a reference to the number of hours on your 30 year old engine, but at least ten thousand seems to be common on a well maintained diesel engine.

I did replace my Westerbeke back in 2000 when it was leaking a lot of oil from the rear seal. That alone, of course, was not a reason to repower, but I was also quite under powered for my vessel's size and I wanted to be able to motor at hull speed.

[darylat8750]

It shouldn't fail all at once with no warning. Are you thinking about leaving on a big trip? If so I would replace the mixing elbow and the raw water pump. Keep the old ones for spares. Add a set of the high pressure fuel lines (the ones between the injector pump and the injectors) and a set of fuel injectors to your spare parts inventory. Keep it clean and painted to keep rust under control and keep the fuel clean. No smoke or strange noises =works good/lasts a long time.

[Stu Jackson]

Originally Posted by ceder

No that's my point. The engine is behaving just fine, the mixing elbow is intact and will for sure work this season as well. But it's as if the general opinion is that the 30-year old engine has to go. But honestly, why?

sailorboy1 had the right answer. This is utter nonsense.

All you're talking about is what is called PREVENTATIVE MAINTENANCE.

Fix the few parts, change the oil and GO.

Have fun. Stop worrying unnecessarily.

My 30 year old engine has 2,980 hours. A friend swapped his out at 5,000 hours and didn't really need to do so, but he wanted a new engine and transmission because he sailed the ICW regularly. He HAD a reason, you don't. I don't either.

I don't have a Yanmar, but I know from my extensive reading that their mixing elbows should be examined closely and swapped out, simply because of the way they are built.

Good luck.

[Cheechako]

If it's been trouble free and not smoking.. keep it. If it has a lot of hours and you are going for long term cruising, just rebuild it.
Yes they do fail, I have had to replace two fresh water cooled 3GM30's with low hours. Cracked pistons. It's virtually the same engine with an additional cylinder.


I don't hear a general opinion to replace a good engine due to age, but maybe due to constant trouble or high hours. Very low hours can be bad also.

[barnakiel]

Originally Posted by Hudson Force

I didn't see a reference to the number of hours on your 30 year old engine, but at least ten thousand seems to be common on a well maintained diesel engine.

I did replace my Westerbeke back in 2000 when it was leaking a lot of oil from the rear seal. That alone, of course, was not a reason to repower, but I was also quite under powered for my vessel's size and I wanted to be able to motor at hull speed.

PLS correct me where I am wrong. I am no diesel mechanic, just a fan.

I believed that the 10 thousand hours life applied to engines like Gardner, old VP (Albin blocks) and today only Bukh (of the common names). And then only in semi-continuous heavy load work (e.g. fishing boats, trucks, etc.).

Is OP's engine the same style or can, in some situations, the same hourage be had from modern, light diesels?

b.

[olaf hart]

A friend recently replaced his Volvo 2003 with more than 8000 hrs on it, it was OK for a rebuild but he does a lot of Bluewater time so he replaced it.

He donated me two spare elbows, one is on my engine already

[Lepke]

My mains are Gray Marines that later became Detroit Diesel. The engines are 65 years old. By recreational diesel standards probably considered heavy duty. I know mechanics and have been doing overhauls since I was a teen. I think a proper overhaul on a known reliable brand is as good or better than a new engine. Much more time is taken on a proper overhaul than in the original assembly. What most people don't see are the factory engines that fail testing and are reworked or sold as scrap.
I come from a commercial marine background where an engine replacement had to be financially justifiable. It always costs more to install a new engine than rebuild an old one. A proper rebuild will last just as long as the original assembly. Maybe longer.

[Cheechako]

Originally Posted by barnakiel

PLS correct me where I am wrong. I am no diesel mechanic, just a fan.

I believed that the 10 thousand hours life applied to engines like Gardner, old VP (Albin blocks) and today only Bukh (of the common names). And then only in semi-continuous heavy load work (e.g. fishing boats, trucks, etc.).

Is OP's engine the same style or can, in some situations, the same hourage be had from modern, light diesels?

b.

I think the jury is out on that... partly due to the lightweight ones not being in commercial applications... so often... they don't get those hours on them. Often a boat may only get 500 hours in 5-6-7 years. A Perkins surely can and more.