Graham376
Well-Known Member
Plenty of '70s boats still around with original engines.
Stupid question
- Thread starter jimi
- Start date
CAPTAIN FANTASTIC
Well-Known Member
The volvo engine on my previous boat was 47 years and going strong and my present BMC 1.5 is the original 39 years old and is doing fine. In my opinion, the key for every engine is to change oil regularly and in my case I use synthetic oil. Also, there is no need to run the engine hard nor to idle them for long periods.
Topcat47
Well-Known Member
Boat engines lives are usually limited by availability of spares. My old MD1b was pensioned off due to unavailability of an exhaust manifold and (at the time) a cylinder head gasket. Price of spares is another consideration. A replacement 1GM10 (exclusive of gearbox) is not a huge amount dearer than a new cylinder head, and gasket set. Don't even think about a replacement Hitachi Alternator....
LittleSister
Well-Known Member
Not to me. I doubt many car engines are worn out at 150k miles, that they average 40mph over their life, or that they are even beginning to be worn out at 3,750 hours.
I get the impression that very few marine engines are actually worn out. They seem more often to die of neglect, or be replaced because of a combination of cost/availability of spares, and that the engines fitted a few decades old are typically thought underpowered and/or insufficiently 'maintenance free' by modern standards.
If it weren't tempting fate
I'd tell you my 41 year old sea-water cooled Bukh seems fine and runs well (though it did spring a shockingly expensive injector pump leak recently).
Laminar Flow
Well-Known Member
Agreed, boat engines sit to death, not run to death.
lw395
Well-Known Member
The computer on my car tells me I've averaged about 40mph.
When is a car engine 'worn out'?
When it can no longer be started? When it loses more than x% of power? when it leaks oil? Maybe when something like a head gasket goes and it's not worth repairing?
Few actually go BANG! with a definitive end of life.
These days many will still be 'functioning' when they fail the MOT BER on emissions.
Boat engines tend to be simpler, but I suspect less precisely made. More like 60s and 70s cars where the engines were sometimes pretty tired at 50k miles, work was usually needed by 100k miles.
People in industry who run generators with similar engines to a sailing yacht seem to regard 10k hours as an acceptable life and 20k as wishful thinking.
jimi
Well-Known Member
Personally I don't rate hours as a measure of knackeredness of an engine as I reckon regular oil changes help preserve working life. I'm more worried about corrosion as the marine environment is not helpful to metal things and its all the ancillary bits that wear out .. not the main donk. However I'm tending to wards retaining the MD2040 as there is now no like for like replacement from Volvo and the engine bay in the S38 is, I reckon, too short to accomodate the longer D2 50 (although I have'nt measured it properly).the Vetus M$.45 might just fit but I'm not convinced of the value of moving to a Vetus. So probably a new saildrive, I think.
Beneteau381
Well-Known Member
Based on a Perkins industrial engine, keep changing the oil and filters and it will go for ever
Beneteau381
Well-Known Member
I took a spare Perkins Prima 50 head (aka VP MD22) to my local machine shop for skimming. An old fashioned one with a man who had been there since Hitler was a lance corporal. He asked how were the bores and pistons. I said still well within spec, he said, I bought some oversize pistons nearly 50 years ago for one of those, the trouble with them is they dont wear out!
Beneteau381
Well-Known Member
Sybarite
Well-Known Member
Ye
Yep.
Kukri
Well-Known Member
The Merlin has a cast aluminium ‘gear case’ at the aft (non-propeller) end of the engine. Quite a lot goes on in here, much of it to do with the supercharger, but the gear case also contains the drives for the camshafts, which are indeed overhead, and are driven by bevel gears which drive angled shafts which drive bevel gears which drive the camshafts. Pretty standard stuff for 1933.
They are not driven by chains, still less by belts!
Stemar
Well-Known Member
A charter boat's engine that's thrashed to death on a regular basis may not last as many years as the auxilliary engine on the boat of someone who loves sailing and only uses the engine to get in and out of their marina berth, barely warmed up before it's shut down again, but it'll last many times as many hours.
I can't help thinking there's some benefit in having an engine that takes a little bit of churning to start. My VP2003 always goes but, when cold, takes enough churning on the starter to get the oil pressure up before firing.
I can't help thinking there's some benefit in having an engine that takes a little bit of churning to start. My VP2003 always goes but, when cold, takes enough churning on the starter to get the oil pressure up before firing.
Beneteau381
Well-Known Member
My link was to show Merlins are OHC. Your post agreed with someone that said Yanmar are pushrod, they are. Your post intimated that RR merlins were the same, pushrod, they aint!
Kukri
Well-Known Member
I was making the point that both have gear driven camshafts. I did not say or mean to imply anything about where the camshafts are in the engine!
Laminar Flow
Well-Known Member
We had to get rid of our old BMC. It became too difficult to source parts for - it would have been a six week turnaround just to get the water pump rebuilt and we would still be in Boulogne, if it had been up to the Uk service providers. The thing also had a bad smoking habit, like a destroyer laying a smoke screen on startup, and a thoroughly abusive relationship with the world's dwindling oil reserves. The new engine uses half the fuel of the BMC. We did keep our old and reliable PRM 160 gearbox. Marine engines live hard lives; it is the sitting, running without load (to charge the batteries) and poor maintenance that kills them, not the running.
pvb
Well-Known Member
And I believe that "gentle" use doesn't help either. We read lots on these forums about exhaust elbows getting caked with carbon. The Volvo Penta 2003T in my old boat was 24 years old when I sold the boat, and the exhaust elbow had never been off. But when I motored, it always tended to be fairly flat out (no point in dawdling).
Zing
Well-Known Member
I asked a Perkins engineer that question and the rough guide was 10,000 hrs to a rebuild then another 8 to 10,000. We run HGVs and they work on similar hours.
