SMOH--accepted definition??

[hattnut]

The term SMOH is used a lot and I am confused what it includes, especially if the main bearing on the crank are not replaced?? Just what is included and excluded in the term SMOH??? comments and advice welcome. It seems to me an engine with 3000 hrs, and due for major rehab should have the main bearing done, even though it is a pain. doing less when you have already torn down most of the engine seems to set you up for failure and a redo in a short time.??

 

[spartonboat1]

I interpret it as "since major over haul". On this site there are gradations of SMOH, since some Detroit Diesels might only be a re-bearing and re-kit in-frame (in the boat), while purists would strongly recommend a full removal of the engine and bench rebuild, crank re-work, etc. A good DD shop such as Williams will charge you $3,000 just for a full blown survey of the engine, let alone a full complete rebuild.

So SMOH can be mis-leading, depending who is making the representation. Should be subject to documentation (bills of work, scope of work, list of materials, shop name, etc.).

One of my mains was an inframe re-kit and re-bearing by a PO (previous owner) and I had issues with leaks at the heat exchanger. This is a J&T (Johson and Towers) DD 6-71N 310hp.

My 2cw...

 

[Brian Degulis]

If the mains aren't done it's dishonest to call it an overhaul. The most accepted definitions are. Rebuilt= Heads, cylinder kits, Main bearings, Rod bearings, Injectors. Blower (s), Fuel pump, water pump. Remanufactured = every wear part on the engine is brought up to new tolerances. Typically no more than 10 under on the crankshaft some allow 20. Doing just the heads and cylinder kits is risky because you've got an new full compression engine on the top and an old engine on the bottom. If your talking about an engine with good oil pressure that's run easy and is only being rebuilt because it's worn out and smokey you can get away with it. But a TI that's working hard you really are risking a bottom end failure.

Brian

 

[yachtsmanbill]

I concur, especially re-sizing the rod ends and checking for straightness etc... ws

 

[Pete]

Another aspect of SMOH is when looking for a boat. The bottom line is sellers will use this term for various levels of engine work and thus the only way to know what they really did is to ask to see the work order and detailed receipts from the job. My attitude is if you do not have receipts with the details, it didn't happen!

Pete

 

[REBrueckner]

SMOH means nothing, so it's always a good idea to verify. I prefer to get a lot of information verbally and then subsequently ask for receipts, records, verification, etc...if something turns out to be a false claim I then assume everything is.

Likely mechanics will mean one thing (and that's likely not going to be uniform either) , owners another, brokers yet another. Most owners have absolutely no idea what an overhaul means (forum members here are the exception). As Pete noted, without a detailed receipt showing parts, labor, and details, assume nothing was done. The idea that an owner doesn't know his own cruise RPM, speed and fuel consumption, for example, or has never had an oil analysis done, but readily verifies his engines have been "rebuilt" or "overhauled" is like trusting the government to take care of you.

When I had a cylinder kit overhaul done on one engine and the heads tested and both engines disassembled for removal,cleaning and pressure testing of the cooling system components the receipt details were three or four pages long...

I see nothing wrong with a top end rebuild/cylinder kit overhaul in a typical cruising boat with moderate HP/cube run at moderate RPM and used a few hundred hours annually. For a high power sport fish that will be run hard, maybe five hundred or a thousand hours annually, it's a very different equation. My old 1970's 8V71TI's at only 435 HP for example are a far cry from newer 671TI's cranking out 575HP. And I'd be more leery of a light "overhaul" done just prior to placing a boat on the market versus one that was done a season or two prior and has some run time.

 

[sandspur1966]

I agree that SMOH is a subjective term with no real definition. I also agree that if you do not have verifiable receipts, the overhaul never happened.

I can see the viability of a true, takeout and bench rebuild with a convertible but as a MY owner I can't imagine anyone going through the exercise of removing the mains and then replacing them with the old technology. I love the old 2 cycles as much as the next guy, but if you are going to open your wallet for the work to take out the engines and rebuild them, the incremental expense for a nice clean, efficient set of QSM's is the way to go.

Again, just IMHO.

 

[Glory]

SMOH means exactly what the invoice for the job says. No invoice available, then it's just a waste of the alphabet.

I would say it's like the "never fished" slogan for a fish rigged boat. I hadn't ever considered fishing something to be ashamed of.

JM