Ball park figure to rebuild/overhaul engine/gearbox ??

[Sybarite]

Say a Perkins 4108 50hp with around 3000 hours ? Maybe 30+ years old.

I haven't a specific case in mind but just to know what to take into a budget if I change the boat.

Are there other choices - eg standard replacement.

How reliable when rebuilt compared with a new one?

Any information will be gladly received with thanks.

 

[oldsaltoz]

a Perkins 4108 50hp with around 3000 hours ? Maybe 30+ years old.

Would be just run in.

Refurbishing old marine engines often features on these forums, a search will turn up lots of responses.

The truth is, it's almost always not worth the effort and cost with older engines, parts not readily available if at all, huge variables in condition due to how well it was maintained, how often it was run and for how long.

3000 hours is not a lot after 30 years and on a road engine would still be running strong. But then vehicle engines don't have to live in salt air with condensation running down the wall of the engine compartment, not to mention extended periods without running during winter.

Any second hand let alone old and second hand engine is a gamble, not worth the risk.

Find a fully reconditioned unit that comes with a warranty from an authorised dealer, on average this will cost you less though your original outlay is more than that "she's only been used to motor in and out of the harbour" job.

 

[saltwater_gypsy]

I agree with oldsaltoz 3000hours is hardly run in.
A lorry will probably average 40mph so that 3,000 hours is 120,000miles. A lifetime mileage of twice that is not unreasonable

 

[cliff]

Why do you want to "rebuild" the engine? - what is the problem?
Low compression? - replace the valve guides if worn, regrind the valves and and maybe a set of rings (unlikely it would need a rebore / sleeves) - not a fortune.
Low oil pressure? check the pressure relief valve - if ok then new oil pump, shaft grind and bearings - again not a lot of money
If pistons are gone then consider scrapping it - diesel pistons are a horrendous price.
Also cost out gasket sets and seals - might get a shock.
Bottom line is until you strip it down you do not know what is needed.
If you pay someone to do the rebuild it will be expensive due to inflated labour costs but the machining work is not that expensive.
One final consideration, injector pump and injector overhauls are pricey.
On the up side the old perkins are easy to work on yourself.
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Artificial Intelligence is no match for Natural Stupidity.

 

[Tranona]

Hours run is not a good indicator of condition. Marine engines die mainly of neglect. While you can rebuild a 4 108 and I guess ball park about £4k - half the price of a new installation, you will still have a way obsolete engine. However if you are DIY and only replace things that are worn you may reduce this price substantially - trouble is you may not know what needs doing until you strip it.

Better to consider each individual boat/engine combination on its merits. The smaller and older the boat, usually the greater the cost of replacing engine in relation to boat value. So £5k on a Westerly Centaur is nearly 50% of value, but similar engine in a Moody 31 would be nearer 20% value.

 

[charles_reed]

A 30 year old Perkins with 3000 hours certainly won't need a rebuild - it would need to be nearer 10,000 hours.

Having done the exercise myself, it's certainly cheaper to re-engine than to pay someone else to do the work.

A total rebuild would cost at least £4500 in parts and machining, if you did the work yourself and about double that for someone to do it for you.

My exercise was on a 2GM Yanmar and parts and machining worked out £250 less than purchasing a new 3YM engine (doing all the stripping and assembly myself) and did not include new insides for the gearbox - which put the whole thing into a nonsense situation.

 

[Gwil]

Marine engines die of things like acidic oil sitting around destroying hardened surfaces in cams/followers/rockers etc. The 4108 is an easy rebuild proposition and parts are available (not so easy for the 4107). But ancillaries will all be tired, heat exchangers will be old etc. That's before you start on the g'box....
If on a reasonable budget you can go for something like a marinised non turbo Peugeot or a Ford- between 1600/2500cc-much cheaper often than the more well known Yanmars/Betas etc.
I have a truly ancient BMC 80hp 6cyl. monster in my boat. Love it dearly though I do, its low revving nature means a biggish prop affecting sailing performance, and its size makes maintenance (16 pint sump!) more difficult. No room either for a thrust bearing/cv joint setup which I would like to fit. I wouldn't rebuild it even if parts were not a problem. Might polish it and keep it as an objet d'art though....

 

[Sybarite]

Thanks everybody.....

My plans to change the boat have taken a back seat to changing the house. Once this is out of the way (on the market since yesterday) I still harbour the notion of a Fjord 33. The worst surprise (I hope) might be the engine and so I would like to know what the worst financial surprise might be. I saw one boat where the owner had fitted a new Mitsubishi (Vetus)42hp and along with an Autohelm 7000 (and other goodies) I was sorely tempted. However given the present times, I could not afford to have two boats on hand and so I had to pass on it.