What Constitutes a Rebuild ?

[sweetsailing]

Hi all,

Looking seriously at a particular boat that has a Yanmar 4JH3BE (year 2000 boat) This engine currently has 2780 hours and was reportedly rebuilt at 1700 hours. What we know of the previous owners, they were very meticulous about boat keeping and maintainance.

Based on this information what questions should I be tracking down? So far, here are our thoughts:

1) Why was the engine re-built?

2) Who did the re-build?

3) Obtain records/invoices of what exactly was done in the re-built (what typically constitues a re-build? Is the term used broadly to describe any number of things that could have been done/replaced?)

4) Would a re-build make you want to conduct a separate engine survey?

Any other things I should be thinking about that I haven't stated?

Thanks

[Fishspearit]

The term 'rebuild' doesn't mean a thing unless it's accompanied with receipts.

It could be anything from 10 minutes with a can of spraypaint, to a full engine rebuild. Everyone has a different definition. The only thing that matters is provable receipts.

[S/V Antares]

An "aerosol overhall" ?. My question (and yours to the owner) is why such a reliable engine would need such work at 1700 hrs.

[avb3]

Originally Posted by S/V Antares

An "aerosol overhall" ?. My question (and yours to the owner) is why such a reliable engine would need such work at 1700 hrs.

My guess is that it spent a considerable amount of time idling. Other than a compression test (both wet and dry), I would have the engine oil analysised. That will give you a good indication of the health of the rest of the engine. It's done all the time with big equipment.

[captain58sailin]

AT 1700 hrs, the engine is barely broken in, maybe the PO got some bad advice.

[Unicorn Dreams]

Shouldn't even think about an overhaul until 10,000 hrs or so

[Tellie]

If the boat is a serious prospect, pay a good diesel mechanic for a few hours of his time. Then do the same for a good rigger, marine electrician, electronics man, etc. If the surveyor happens to be there at the same time ask him kindly to stay the hell out of their way. As Fishspearit stated, if there are not provable reciepts a claim of a re-build don't mean doodly squat.

[JiffyLube]

A "complete" rebuild will involve tearing down the entire engine, not just rebuilding the top end. I've had truck engines completely rebuilt in the past, and the work will only be as good as the mechanic doing the work. If I was in the situation again of deciding whether to rebuild or re-power new, I'd go with new. As mentioned, receipts will be the only evidence of what kind of rebuild it was.

[sweetsailing]

Thanks for all the replies so far. Most definately will be asking about why the re-build was done and will be asking for receipts, etc from the work that was done and details of what work was done. Aside from the receipts, much of this information will be anecdotal at best. Will the engine survey tell me what I really need to know? What advice do you have about locating an appropriate marine mechanic?

I do know this boat was extensively cruised in the caribbean, east coast and pacific to Hawaii from 2003 to approx. 2009. I do know that the re-build occurred during this time period.

This boat is a serious contender and all other items at this point (pre-survey) are not yet raising our eyebrows

[forsailbyowner]

There are several questions to ask about a rebuild. A true rebuild will bring all clearances to factory specs. Some shops check clearances and if they are anywhere near the center of the service limits let it go as there is service life left in the parts. When I open an engine I plan on restoring all parts to factory. The labor for engine removal and disassembly make the cost of bearings and machine work pale in comparison. Even with reciepts you dont know the whole story about projected engine life without the clearance numbers that tell the real story.

[avb3]

Originally Posted by forsailbyowner

There are several questions to ask about a rebuild. A true rebuild will bring all clearances to factory specs. ...

Pretty hard to bring worn cylinders to factory specs with out replacing the block. Usually they are sleeved or if bored, over-sized pistons are put in, in my experience.Crankshafts may be turned if a bearing was spun, but that is pretty unusual in most diesels.

[Unicorn Dreams]

Mu last engine I resleeved it with the new pistons. All depends on the engine make.

[Catamount]

If the condition of the engine is an important consideration in the purchase of this boat, wouldn't you want to commission a specialized engine survey regardless of whether there was a "rebuild" in this engine's history?

[Tom1340]

Sweetsailing,
I see 'your' boat is showing as 'sale pending'. Are you the buyer? If so, have you learned the reason the owner totally rebuilt a 'new' engine... and is there a story the rest of us can learn from?
Good luck, she looks a fine boat.

[forsailbyowner]

Originally Posted by avb3

Pretty hard to bring worn cylinders to factory specs with out replacing the block. Usually they are sleeved or if bored, over-sized pistons are put in, in my experience.Crankshafts may be turned if a bearing was spun, but that is pretty unusual in most diesels.

A proper rebuild can include oversize pistons and still be in factory specs. The specs would be referring to cylinder taper, skirt clearance, out of round, ring gap, ring groove clearance etc....