When to Re-Power?

[Exocet]

At what point would you repower your boat?
I have been told that the life span of most small Deisel marine engines is about 25 years (true or false). If true, and at that age, which choice would be made, a re-build, or re-power?
Please include all pro's and con's you can think of... Cost, reliability, parts availabity, and thoughts on a re-powering with a used but newer motor.

[Boracay]

1) Your engine won't start without obscene amounts of ether.
2) Your boat interior is coated with gunky, black old engine oil.
3) Quotes for maintenance are more than the cost of repowering.
4) Engine sales persons suddenly seem to be your best friends.
5) You can't tell if your gearbox is in reverse or forward.
6) Your spare parts bin is larger than your engine.
7) There is no mention of your engine model anywhere, and the manufacturer doesn't want to know you.
8) The last time you spent a couple of boat bucks on the engine you don't know what it was for.
9) You've rebuilt the fuel system from tank to injector pump and it didn't help.
10) You can bleed injectors in your sleep.

[Blue Stocking]

Yep Boracay!!, I think you just about nailed it.

[nautical62]

I think engine life can vary as can when it makes sense to repower instead fo maintain.

My first boat was pocket cruiser. The original inboard diesel was 28 years old when I bought it. The cones were already slipping. It was clear it was in bad enough shape that rebuilding probably wasn't worth while. Replacing it would have cost almost as much as the boat and was out of my budget. I ran it until it absolutely died 3 years later, just outside Green Turtle Cay, Abacos, after which time I simply switched to sails only. I didn't even have a dingy outboard motor at the time. Eventually, I "repowered" that boat with an outboard, which sufficed for many more Bahamian adventures.

Looking back, it was the right choice, but not the choice I'd make now with my current boats.

[Pblais]

I'm more inclined to agree with Boracay. An engine however is more than just the engine. All the stuff attached to it relates to the engine and may have to be replace just because you wanted to replace the engine. There are replacement options that minimize this.

An overhaul on an engine is not uncommon and it's worth investigating unless you just need to lighten your bank account a lot of money. Diesels are designed with a rebuild in mind unlike automobiles. Rebuilds are done by hand and can be as good as new unless the engine just was too small to begin with.

[Cheechako]

If it's a Perkins, definitely worth rebuilding and the parts are available. Some of the other "slow turning" diesels may be worth rebuilding also, although Perkin's parts may be the ones readily available. Ford Lehman are likely worth it too. If done properly and IF your mechanic says the block is good enough to do so. As Pblais points out, the peripherals should be renewed also. (alternator, lift pump, transmission etc...)

[zeehag]

westerfreeeeked!!!! lol


this is whenya repower---up to this, rebuilding is goood---at about 600 hours, freshen the engine with an overhaul....is always a goood idea--maybe at 25 yrs is also a good idea if the funding is available..lol...btw--ii didnt do this--previous owner blew the bejeeeziz outta dis ting trying to muscle off a shoal...didnt maintain it regularly , either......new perkins is awaiting install---just 18 inches from this one!!.

[redcobra]

1. When you have to hold the preheat button for over 5 minutes and it still barely sputters to life.
2. When it overheats and has to be shutdown just as there is no wind and you are drifting towards a lee shore.
3. When Torrenson Marine Diesels says " you can put a note on our forum to see if anybody may have the part."
4. When the diesel mechanic says "Oh, that engine."

[Sail Warehouse]

I might add; If you have a Volvo... ; )

[zeehag]

btw--the engine with the guinness stout sized hole, above, that i showed in need of repower---had less than 100 hours on it---and a total idjit for an owner----blew it up in front of my virginia eyes lol......had also 2 holes in pan!!!! the repower 4-108 is perfect and purrrs like a snow leopard!!!!......many times a rebuild or refreshening of the engine is enough---sometimes is not!!

[bobfnbw]

Originally Posted by Boracay

1) Your engine won't start without obscene amounts of ether.
2) Your boat interior is coated with gunky, black old engine oil.
3) Quotes for maintenance are more than the cost of repowering.
4) Engine sales persons suddenly seem to be your best friends.
5) You can't tell if your gearbox is in reverse or forward.
6) Your spare parts bin is larger than your engine.
7) There is no mention of your engine model anywhere, and the manufacturer doesn't want to know you.
8) The last time you spent a couple of boat bucks on the engine you don't know what it was for.
9) You've rebuilt the fuel system from tank to injector pump and it didn't help.
10) You can bleed injectors in your sleep.

Well to play the devils advocate....

I don't want my boat covered in gunky black oil, so I would not wait that long...
I guess it depends on how reliable you want your boat and engine to be. If you are off cruising in far away places or in dangerous places, like shipping lanes.... or rely on your engine for charging batteries.... or have your family aboard....
Seems to me that the cost of buying a old boat (like mine) should factor in the cost of a engine replacement or rebuild.

pros for a replacement are: less vibration less fuel more power at the shaft, less noise, more years of reliablity.
cons are cost and will it fit

pros for rebuild are: you know it fits. and it costs less.
cons are its not a new engine.

I guess it depends on how you use your boat. I almost never heard of someone saying they hated their new engine, but have heard some say they are sorry they rebuilt vrs a a new install.

I will go for the new install if at all possible, and If I rebuild, it will be until I can afford a new install.

Bob

[David M]

Get an oil analysis done. This will remove much of guess work.

[Ex-Calif]

Just to clarify the terms

- Overhaul = tearing down, restoring all machined surfaces and replacing consumable parts.

- Repower to = Change to a different engine type

When to repower?

- The engine is gasoline fueled
- The engine was not common enough to find parts for it in Tonga
- The boat was underpowered

Overhaul?

- All the above reasons are valid
- Compression checks are low
- Oil analysis indicates metal generation

[Ziggy]

The age of the engine is not a criterion for replacement. I repowered a year ago because 1) I gradually lost compression to the point where it was impossible to start without heroic measures; 2) the crankcase cover was rusting out; 3) the engine was raw water cooled and I was concerned about invisible corrosion inside; 4) replacement parts were expensive and I needed more and more of them each year (sounds a bit like Boracay's list, actually). No single one of these would be a reason enough to replace. For example, if the engine has wet cylinder liners and replaceable valve seats, it would be a good candidate for a rebuild. Repowering can be a lot more expensive than just the cost of the engine (unless it's a drop in replacement, you do most of the work yourself, and you resist the temptation to upgrade everything surrounding it.)

[Pblais]

Just consider that everything bolted to the engine is not included with a new engine. A new engine may not fit or align with the current mountings either. All those engine parts need to be compatible or replaced. The cost of a transmission and all the assorted door prizes adds up to real money too. Most diesel engines can be rebuilt. It can be a time to assess all the other parts too.

Re powering is often thought to be better only because there is a general sense with many people that if it were all new everything would be perfect. It's a nice idea but there is a huge cost. If the money does not bother you then it really does not matter. Rebuilding engines is a job for pros with the shop to really do things right.