Why do people replace diesel engines in a sailboat?

[newhaul]

Originally Posted by Chotu

Another thread got me to thinking. Why is it that people decide to re-power?

Assuming you have a working engine, a diesel engine, what is the point?

I see a lot of people pull out older engines and put in a brand new one. I’m thinking of ones like an old Perkins. Sure, they look old. And they probably don’t get as great fuel efficiency as the new ones. But why replace them if they are still running?

cost of overhaul vs new when off for extended remote cruising there is the expected reliability factor for those not as mechanically inclined

[El Pinguino]

Originally Posted by newhaul

cost of overhaul vs new when off for extended remote cruising there is the expected reliability factor for those not as mechanically inclined

and even if you are mechanically inclined there is the issue of availablity of parts for older engines. You can be as mechanically inclined as you like but if you don't have the bits.....

Mind you I know of someone who was stuck up a caleta without a paddle when a Yanmar with less than 500 hours on it had a starter motor that decided it was no longer a team player....

[RaymondR]

If you are going to re-engine you should do it whilst mechanical pump engines are still available. Common rail with it's dependence on electronics is not the way to go on boats where reliability is a number 1 issue.

[NPCampbell]

Interesting discussion.

I'm restoring an old car that had a gen 1 small block 350 in it. I could have rebuilt the engine to meet my horsepower and durability requirements but by the time I was finished, a modern LS3 engine would surpass it in horsepower, weight, efficiency, reliability, emissions and surprisingly cost.

The benefits of a new engine vs my old were:
1) 150 pounds lighter due to aluminum block, head, intake and water pump
2) Much higher horsepower due to better breathing and combustion from CFD designed and CNC milled heads and intakes.
2) Higher compression ratios because aluminum dissipates heat better than iron
3) Stronger, longer lasting bearings due to better metallurgy (bi-metal vs tri-metal)
4) Much stronger but lighter cranks, rods and pistons due to the mastery of the forging process
5) Engine durability and efficiency improvements like piston oil squirters and roller cams
6) No leaking seals 1 year after a rebuild because the tolerances of modern casting and CNC finishing are an order of magnitude better than 20 years ago

I know all of these things don't translate to a diesel but it's interesting how completely opposite it is to the general vibe that sailors have when it comes to rebuilding.

[newhaul]

Originally Posted by El Pinguino

and even if you are mechanically inclined there is the issue of availablity of parts for older engines. You can be as mechanically inclined as you like but if you don't have the bits.....

Mind you I know of someone who was stuck up a caleta without a paddle when a Yanmar with less than 500 hours on it had a starter motor that decided it was no longer a team player....

That's why I like my md2 it can be hand cranked

as of now the only parts I don't have spares of is the md2 specific parts like the block and crankshaft , 90% of the rest will fit the md1 md2 or md3 platforms. As well as I can scavenge off of the md11 and the md17 series.
If not for that it would be stupid expensive .

[newhaul]

Originally Posted by NPCampbell

Interesting discussion.

I'm restoring an old car that had a gen 1 small block 350 in it. I could have rebuilt the engine to meet my horsepower and durability requirements but by the time I was finished, a modern LS3 engine would surpass it in horsepower, weight, efficiency, reliability, emissions and surprisingly cost.

The benefits of a new engine vs my old were:
1) 150 pounds lighter due to aluminum block, head, intake and water pump
2) Much higher horsepower due to better breathing and combustion from CFD designed and CNC milled heads and intakes.
2) Higher compression ratios because aluminum dissipates heat better than iron
3) Stronger, longer lasting bearings due to better metallurgy (bi-metal vs tri-metal)
4) Much stronger but lighter cranks, rods and pistons due to the mastery of the forging process
5) Engine durability and efficiency improvements like piston oil squirters and roller cams
6) No leaking seals 1 year after a rebuild because the tolerances of modern casting and CNC finishing are an order of magnitude better than 20 years ago

I know all of these things don't translate to a diesel but it's interesting how completely opposite it is to the general vibe that sailors have when it comes to rebuilding.

there is also the whole cluster that you can get yourself up the creek with in electronics would much rather mechanical injection . Works without electricity just like a good old carb.

[NPCampbell]

Originally Posted by newhaul

there is also the whole cluster that you can get yourself up the creek with in electronics would much rather mechanical injection . Works without electricity just like a good old carb.

LOL. My ONLY requirement when buying an outboard motor for lake boats is that it be fuel injected with electronic ignition. It didn't matter how good a job I did winterizing the engine, it seemed like once a year I'd get out to the lake and have the motor not start while sitting on the ramp. My days of buying a carb kits, cleaning jets, syncing carbs, setting points and changing the impeller YEARLY are gone I hope.

[newhaul]

Originally Posted by NPCampbell

LOL. My ONLY requirement when buying an outboard motor for lake boats is that it be fuel injected with electronic ignition. It didn't matter how good a job I did winterizing the engine, it seemed like once a year I'd get out to the lake and have the motor not start while sitting on the ramp. My days of buying a carb kits, cleaning jets, syncing carbs, setting points and changing the impeller YEARLY are gone I hope.

even with your electronics and injection systems 2 things you should do
1) use non ethanol fuel
2) change your water pump impeller at least every other year ( if not annually)
it is your engines cooling system and has nothing to do with the fuel system .

[Cheechako]

I think it's mostly people who want to go out long distance cruising and don't want engine issues along the way in timbuktu. At least that's their thinking... right or wrong.
The other side of that coin is there are more controls etc on new engines now days, hard to say if they are more reliable or less reliable than an old engine.

[Chotu]

Originally Posted by NPCampbell

LOL. My ONLY requirement when buying an outboard motor for lake boats is that it be fuel injected with electronic ignition. It didn't matter how good a job I did winterizing the engine, it seemed like once a year I'd get out to the lake and have the motor not start while sitting on the ramp. My days of buying a carb kits, cleaning jets, syncing carbs, setting points and changing the impeller YEARLY are gone I hope.

Same here. Outboards are just not reliable without EFI.

[newhaul]

Originally Posted by Chotu

Same here. Outboards are just not reliable without EFI.

non ethanol fuel.
My 1972 monkey wards 2.5 runs s great starts first or second lull every time .

[CharmCityBoater]

I was just faced with this. chose to rebuild my existing engine. I had a leaky, rough running Perkins 4.108. Total rebuild cost was $6800. Cost to repower would have been $20k. No brainer to rebuild vs. repower. The Perkins 4.108 is a rock solid mechanical engine though. I might have made a different choice with a not-so-well designed engine.

[rbk]

Originally Posted by NPCampbell

LOL. My ONLY requirement when buying an outboard motor for lake boats is that it be fuel injected with electronic ignition. It didn't matter how good a job I did winterizing the engine, it seemed like once a year I'd get out to the lake and have the motor not start while sitting on the ramp. My days of buying a carb kits, cleaning jets, syncing carbs, setting points and changing the impeller YEARLY are gone I hope.

Haha, you haven’t had the pleasure of replacing an outboard ECU, stator or rectifier yet. They all seem to go at some point and all seem to cause the destruction of their neighbouring part. Rectifier blows which burns out the ecu, meanwhile you limp home in safe mode while slow cooking the stator. Not knocking them completely, they are quieter and more efficient.

[gallatin1988]

For those of you in the know,

How does lack of use or extremely infrequent use factor in to engine reliability?

The boat I'm looking at has the original (circa 1978) Picses (Izuzu) engine in it. Maintenance records are spotty at best. It has seen almost zero use in the last couple of years.

The boat has has also spent perhaps at least 2 years (my guess after talking to the current owner who doesn't know) or maybe more on the hard in the last decade.

To my eye, it looks pretty rusty but it could just be cosmetic.

About a month ago a mechanic was able to it running (at least for 20 to 30 minutes) with very little trouble (oil change, filters, etc). If this means anything at all I don't have the experience to judge.

In it's current state I'm not sure I can trust the engine.

[Chotu]

gallatin1988-

This is not backed up by any evidence or science. This is a personal belief of mine.

I have inherited plenty of old and barely used diesel engines in my time. In my opinion, as you start to put them into regular use, they kind of come back to life. I feel like the breakdowns are going to happen in the first few hundred hours after sitting a long time. Then after that, they kind of get into a groove.

OK Internet, please yell at me now. LOL