What is the life of an engine?

[JamesS]

We're looking at changing boats and are generally attracted to vessels about 10 years old. This of course means you are buying a ten year old engine of doubtful history.

As we intend to extend our cruising range, reliability is important.

Realisically, at what stage do you dump the engine and replace with new in the interests of long term reliability?

Any views appreciated.

 

[hlb]

Depends on the engine. It's not unusual for truck engines to do a milion miles, before a rebuild. Ten years in a boat isn't old.

No one can force me to come here-----------
----- I'm a Volunteer!!!

Haydn

 

[billmacfarlane]

It's very difficult to say. If you know the engine hours , service history and get a mechanic to check it over , then you'll probably be getting a reliable engine that'll still have a long life in front of it , provided you keep up the maintenace. I said probably because you've still got a 10 year engine on your hands .

 

[extravert]

Here's my story. I bought an 11 year old boat, and 3 years later I am having to re-engine. The old one is perfectly repairable, but the cost of labour and spare parts is so prohibitive that it's not worth continuing with. I need a new head (old one has been skimmed to its maximum) and a new sail drive leg (old one is corroded and letting sea water in to the gearbox oil). The cost of these parts is £1800, and the engine needs to come out to replace the leg, so labour will be expensive too.

I've heard somewhere that if the cost of repairing an old engine is more than 40% of the cost of renewing it, then repair is not worthwhile. The cost of spare parts for marine engines is so high that it seems that this limit will be reached if only one or two non trivial items need replacing.

I would say that with a 10 year old engine it may go on for ever as some people are suggesting, but be prepared for it become uneconomic to repair at any time, requiring replacement.

 

[Buck]

There are a number of factors governing the longivity of an inboard enging including regular oil changes and general servicing, as pointed out the external drive arrangement is another point to be aware of, this should be inspected during survey. hlb says that ten years is not an old engine, and he is correct in motor boat terms but in sail boat terms it can be a different matter, it is the under use of these engines that causes premature wear, such as the short usage to get the boat onto moorings etc... this type of use means the engine never reaches proper operating temperature which means internal condensation and inadequate lubrication causes excessive wear, indeed it is the engines that are used a lot that last the longest, i.e. I have seen motor sailers with 5000+ hrs on the original engine and still running fine but racer/cruisers needing an engine rebuild after 1000 hrs, the best solution to your problem is to get a good auxilliary outboard and a way of attaching it to the boat, preferably one that can be used on your dingy or tender as well, a new Tohatsu can be bought at reasonable cost and is usually available at a discount, I find these to be great motors, very reliable and use nothing else given a preference.

Buck

The thing about men and fish is one is always trying to eat the other.

 

[Chris_Stannard]

Depends on the Engine

Reading recent posts if the engine is a Yanmar it is likely to be okay.

If it is a Volvo then I can only quote experience with the 2003. I did my own head overhaul and it cost about £450 including new sleeves for the injectors, gaskets and so on and new fuel pipes from the pump. The engine is now quite sweet.
I was thinking of buying a workshop reconditioned engine, which would have cost about £2750, plus the charge of lifting in and out. However a friend of mine had a piston ring go on the way to Cherbourg. The workshop there lifted the engine out, rebuilt it including new bearings and journals, and put it back for £1100 but that was last year. It took about five days. In my view had he had the starter motor and alternator rebuilt at the same time he would have had a new engine. If you are considering this as a course of action please check with the guys at Cherbourg before you venture there.
If you are going long distance and away from marinas, you might consider fitting a second alternator kit to improve the charging, and so you have a standby in case of problems.
Best of luck


Chris Stannard

 

[Will_M]

How longs a bit of string????

I've got a short bit of string, a medium bit and a long bit... Take ya pick.

 

[Chris_Robb]

Depends on how its used and looked after

NEver buy a little used engine - even in 3 seasons it can carrode.
Always look for proof of regular oil changes - at the end of the season, not the beginning!

Engines like the Perkins 4236 go on for ever - mine is 1977 vintage, and is over 11,000 hours. only fault is it leaks oil from the main bearing!

Preventative maintenance is the key to long life - ie never overheat it because you didn't change fan belt or impellor so change these every year.

Keep the tanks free of water etc etc.

 

[Mirelle]

35 years, in a sailing boat

My Volvo MD2 was installed in 1967 and has been pronounced fit and healthy for another season at least. Bottom end rebuild in 1987. The sea side water pump shaft seal has failed, and it is not worth rebuilding the engine to fix this, so when and if the oil side seal goes that will be it, but that happens on much, much younger engines. I am told that the faster revving, higher BMEP, MD2B is not so long lived, however.

 

[numenius]

I echo what Chris Robb has said - I have a perkins 4108 of similar vintage - I have a suspicion that the modern engines will have VASTLY shorter lives.
I was considering re-engining to a more powerful modern one, but everything I hear and read (especially on these boards) leads me to belive that I'll nver get the reliability or sheer "just keeps going'ness" of my Perkins - and at the end of the day, thats most important to me (it's a motor boat). So I guess it also depends on the make as well as the use the engine has had.

http://members.lycos.co.uk/boaty1965/index.htm

 

[vyv_cox]

My Bukh 20 was about 16 years old when we replaced it, although it was still in pretty good condition. We were in the situation that the boat was underpowered and we are preparing for a (hopefully) long and happy retirement in the not too-distant future. On these grounds a replacement could be justified but the Bukh was sold on and is running fine.

As others say in this thread, age alone is not much of an indicator of condition. Brief operating times, long periods of inactivity in damp, cold conditions, poor fuel and oil, may wreck an engine in a very short time, whereas an engine used daily will last ages.

My GK29 was built in 1979, when a secondhand Yanmar 12 was installed. We had no trouble with it, sold the boat about 7-8 years ago and as far as I am aware, the engine still runs fine. That engine must be at least 25 years old but could well be a lot more.

 

[JamesS]

Re: Depends on the Engine

Thanks for this - I am well aquainted with the guys in Cherbourg - they did an excellent repair for me after a valve blew mid channel a couple of years ago.

At a very reasonable price too!!

Cheers

 

[bedouin]

Re: 35 years, in a sailing boat

My MD2B has just celebrated its 30th birthday - it's still going strong so there is no reason to believe it won't last another 10-20 years.

The thing which concerns me most is the external rust in places that are very difficult to reach

 

[hillyarder]

Petter 12hp twin. still going strong. been in the boat since 1966.
touchwood.

 

[chippie]

A mate of mine had a gaff cutter with a 19 hp Gardner that had allegedly been in the boat since it was built in 1939. A wonderful old motor that probably owed its longevity to low revs and a big flywheel. It also had a miserly fuel consumption. The fellow he sold the boat to sold the engine to a classic boater from England. It's probably still going strongly.

 

[Mirelle]

Re: 35 years, in a sailing boat

You have the positively sybaritic luxury of a starter motor and a Bendix drive! We have a Dynastart - but we did add an alternator, about 17 years ago.

An inch of iron produces 15 inches of rust, they tell me, so I am quite relaxed about that! I did ask at the Boat Show once, and was told that Volvo don't know when it will rust through, because none ever has, so far!