Diesel Engine Repower & Overhaul - Facts request

[WoodFamSkipper]

Hi All
Looking for any prior experience and factual metrics of engine replacement or rebuild scenarios you have had in the past. Monohulls and Catamarans

In a questionnaire type format could you tell me:

If Replaced
How many hours your engine had?
What HP was it?
What Age and Manufacturer?
How much did the replacement engine cost ?
How much was needed for additional parts to complete the solution?
How much cost / time was the labour?

If overhauled/rebuilt
How many hours your engine had?
What HP was it?
What Age and Manufacturer?
How much was needed for additional parts to complete the solution?
How much cost / time was the labour?
Was it more economical than replacing?
How much more life did you get/expect out of your block?

Was your reason based on a "Need to" or it's "Better to" have done?

I'm shopping for boats now and find that so many come with a lack of service history, or proof of maintenance. Coupled with being told "Oh it'll go for 10,000 hours at least!"
I'm just looking for cost comparisons and scenarios to aid purchase planning

Thanks in advance to all!

[boatsrus]

I replaced a 25hp volvo md2b engine at 43 years old on a sail boat. I was trying to get to 50 years old. The engine was in poor condition when I bought the boat - but I change piston rings in 1 cylinder and cleaned out the water cooling path. I got the block welded in a couple of places - which is not that easy on a cast iron block.

As the engine wears you the oil pressure drops as the engine gets hot up until it gets to zero at which point the engine seizes. A oil cooler will help a lot.

After sailing in heavy weather where I had to motor - I decided to replace the engine.

I had not realised how easy it is to get the old engine out of the boat. Had I done that earlier - I could have got the old engine refurbished much easier by sending it to a specialist - which would have been cheaper.

For the new engine - i moved the throttle location and had to reposition the control panel - so some fibreglass work required. I also had to find a box to mount the control panel in.

I also got new engine bearers and new exhaust. Getting the geometry right was not that easy. The weight of the new engine was different to old engine.

I had to replace the thruhull and seacock with a larger unit. (On my boat the hull was very thick - so that took best part of a day.)

The new engine needed a oil cooler for the prm gearbox which had to be fitted.

I had engine mounts - but they were not strong enough with the engine sloping - so I upgraded 2 of them.

I did not replace the prop shaft - but needed a bobbin to join the gearbox to the coupling which I got made.

I spent about £2500 on the parts and fitting - including the limited professional help I had.

Dadsrus

[Sojourner]

Just had rebuilt our Perkins Prima M80T. Almost 8000 hours on the clock, still pushing good enough but was feeling tired and we were planning on a longer voyage sooner so thought it was best to have her rebored/refurbished. Reasoning was this engine has very little electronics and no common rail, making field repairs simpler. Got a quote from a reputable shop for I think 7000 bucks including new everything that can be new, rebored 1mm larger (engine's first overbore), etc.

Got it done, but had lots of oil eating problems due to probably crappy job. Had everything tested again, pulled again, new turbo for 800 bucks. Still smokes like I do (2 pack a day) and eats a quart of oil every 50 hours now with 200 hours on it. Something is wrong, and this winter going to have to make some choices.

Was offered a Volvo Penta D3 for about 4000 euros, with about 3500 hours on it. Refused because I read way too many problems with the electronic nature of those engines. Not their best at all. YES YES I KNOW many people have them and had no problems. But those that did have problems, you can't fix them yourself in many cases. Not only that, a great diesel mech you find on an island somewhere can't fix it either. Only the volvo rep with a black briefcase and laptop can. So that was out.

A friend got a new yanmar 120-something HP for his yacht, cost about 22k if i recall correctly. I'd do a yanmar over the D3, but don't have the scratch. Besides, I found something better....

Doing a LOT of research (including here on this forum), it seems impossible to find a Beta owner who is even slightly unhappy with their choice, or even one that doesn't say it was the best thing they've ever done for their boat. So this coming winter layup in Palermo I have a Beta 75 sourced for 13,000. Their custom feet mean I don't need to modify the rails to get it in my engine room. Very basic engines, no turbocharger, just a solid marinised tractor engine that will go forever and the parts can be cheaply sourced from Kubota agricultural outlets all over the world and that I can repair with 2 screwdrivers and a hammer, just like my old VW bus. So most likely, what started as a refurbishment will end up as a full repower, rather than throw money at this perkins anymore.

Anyone want a rebuilt perkins this winter, by the way?

[Lepke]

Unless the engine exploded, it's always cheaper to rebuild than replace. If you replace with a different model, then you have a lot more work that may include new engine beds, exhaust, fuel lines, battery cables, raw water plumbing, etc.
I rebuild my own engines and only have labor for head work, machining, and injector rebuild. If you're going to long distance cruise you should learn the mechanics of whatever engines you have.

[tkeithlu]

You're not going to get a big enough sample with your survey to reach any conclusion other than Lepke's "Unless the engine exploded...." You might be better off doing a careful analysis of the engine on any boat that you are considering. Compression, even compression, smooth running, been opened before, oil analysis for metal content, starter/star gear, evidence of care, and a bunch more that Lepke could suggest.

[hpeer]

I think Lepke is looking at it the right way. New engine cost is only a part of overall cost, all the other bits can add up to quite a bit.

Along those lines, considering you are not going to be able to rebuild the engine yourself, I would research which engines can be had rebuilt off the shelf.

For example our small boat has a Volvo an ancient Volvo MD7A. Left hand drive. To change out to a Beta/Nani I need to redo the exhaust, replace shaft, replace prop, change mounts, new control panel. I picked up a spare MD7A I could have rebuilt for less than the cost of the extra work above. AND the swap would be a drop-in, might be able to do it in the water. Take a couple of days if all goes well.

Or on our big boat it has a Yanmar 4JH4. That’s a pretty common engine, I think they are readily available both rebuilt or new that would be near drop in.

But what about a Ford Lehman? I understand someone is rebuilding them, single source of supply. Or a Perkins 4-108? Is there a good source of supply for them? Not a clue.

[a64pilot]

Originally Posted by Lepke

Unless the engine exploded, it's always cheaper to rebuild than replace. If you replace with a different model, then you have a lot more work that may include new engine beds, exhaust, fuel lines, battery cables, raw water plumbing, etc.
I rebuild my own engines and only have labor for head work, machining, and injector rebuild. If you're going to long distance cruise you should learn the mechanics of whatever engines you have.

I agree 100%, but I’ve overhauled a many an engine and wouldn’t pay someone else to do it anymore than I’d pay someone to mow my lawn, if I still had one.

However there is an exception to that, if the engine manufacturer has “orphaned” that model of engine and parts are no longer available, then your pretty much forced into replacing it.

I don’t think my Yanmar 4JHE is there yet, but it’s coming.

[a64pilot]

I thought the Perkins 4-108 was used in the US in the Massey Ferguson tractor?

[FPNC]

The answers to all the questions you have asked will have a variable based on past maintenance, past deferred maintenance, past use, past abuse, engine model, transmission model, and the model and locality of the vessel.

What are your personal expectations? Are you using the vessel locally on a bay or do you expect to sail across oceans?

Rebuilds can be very economical or very expensive, very reliable or a botched up mess. Some diesel engine models are absolutely not worth rebuilding.

The best thing you can do is price a vessel purchase based on either your total confidence in the engine, or a total engine engine replacement. Things get sticky in the middle.

[a64pilot]

A large problem with an overhaul is several fold, some consider scuffing up the cylinders with a dingle berry hone and new rings an “overhaul”. Oh, throw in some new spray paint. Some believe its replacing all parts that can wear.
Plus an overhaul is as good as the overhauler and no better, so they are all over the place.
Usually any warranty is also suspect too.

However done correctly an overhauled motor is better than new in my opinion, tolerances can be held tighter and it’s a “seasoned” block too.
Many people that build racing motors are of the opinion that due to aging and heat cycles and old seasoned block is stronger than a new one.

Overhauling your own motor is an excellent way to save money, end up with a high quality product and gain knowledge about your motor that you just can’t get any other way.

[KadeyKrogen38]

Perkins 4-108’s are very popular fork lift engines as well.

[moseriw]

Fact: do never ever renew an old <<1990 Volvo, Catapillar, Ford Lehman or any engine that has much litres and low service rpm's. I am talking about <2000 rpm.


Renewing it means changing gold against mud.

[michaeld]

I can't speak for a rebuild, except to say that rebuilding a 20+ year old block is possible, but finding parts down the road may be your nemeses. I chose to replace our 25 year old Universal with a BetaMarine. As said above, you can source all non-marinized at any Kubota tractor dealership. I was extremely happy with performance and after the sale support from BetaMarine, NC, USA. Our current boat has a Westerbeke 71C, and I have yet to determine exactly what engine block make/model it was based on.

[BrianGJS]

We had 1100 hrs on Yanmar 6LYA-STP 370 hp that broke a crankshaft. Out of pocket cost for reman was about $55K.

[jcdexter]

I re-powered my Brewer 12.8 with a new 75hp Yanmar. The engine I replaced was a Peugeot blocked Lehman and parts including a dip stick and head gaskets were simply not available. The old engine still ran well but was beginning to burn oil. We were cruising back and forth from the Chesapeake to the Exumas and the thought of having a breakdown far from home and a yard that could replace an obsolete engine seemed way too risky.

Before you consider rebuilding make sure that parts including water and fuel pumps and other peripherals are and will be available for the life of the rebuilt engine.