Yanmar Engine Hours

[trapezeartist]

What can reasonably be considered the life of a Yanmar 3GM30F engine? Is there a case for saying that a high mileage engine has spent less time sitting around doing nothing but corroding and may therefore carry it's hours better?

 

[peter2407]

Maybe align engine hours to the same for a car (I was looking at this the other day, being sad ie married with kids ..) - Yanmar services go in steps upto 600 hrs. If the standard Yanmar 30 can get up to 6/7 Knots that means c. 36-42k miles. Back to the car analogy, that means regular servicing and replacement of major components means you can keep a car going for say 120k miles (possibly the equivalent distance for a boat engine?). Add to that Marine Diesel engines are essentially floating tractor engines, then who knows? Anybody want to set the record for engine hours?

 

[Fr J Hackett]

It actually depends on how well the engine has been maintained and how its been used so no such thing as average but all things being equal at least 3500 hours or 15 years plus. I recently changed one at exactly that because the crankshaft oil seal had developed a large leak. Other than that the engine was fine started every time and is still running I chose to change it because by the time I had taken it out of the boat done the work put it back in etc I would still have a 15 year old engine and I was unsure of its maintenance regime for its first 8 years and would have spent time and money with no idea of how long it would last.

 

[jason -and the arguenauts]

What can reasonably be considered the life of a Yanmar 3GM30F engine? Is there a case for saying that a high mileage engine has spent less time sitting around doing nothing but corroding and may therefore carry it's hours better?

Yes. The greatest wear in an engine occurrs when it is starting up, is cold and has little oil circulating. Thats why rep's cars at 100k in a year are often better than the little old ladies car doing 2k per year

 

[trapezeartist]

A picture is evolving, but more opinions would be good.

"At least 3500 hours": so 5000+ is getting a bit long in the tooth

Yes, I'm well aware or the ravages of cold starts on an engine, and I cringe when I hear engines revving their nuts off on a cold morning. In the case of a marine diesel, there's also the question of the relative wear-rate when an engine is just being used to charge batteries. It will be slow to warm up of course, which can't be good, but is there any other bad news to balance the low stress regime of running at idle speed for hours at a time

 

[sailorman]

A picture is evolving, but more opinions would be good.

"At least 3500 hours": so 5000+ is getting a bit long in the tooth

Yes, I'm well aware or the ravages of cold starts on an engine, and I cringe when I hear engines revving their nuts off on a cold morning. In the case of a marine diesel, there's also the question of the relative wear-rate when an engine is just being used to charge batteries. It will be slow to warm up of course, which can't be good, but is there any other bad news to balance the low stress regime of running at idle speed for hours at a time

Kabota Minidigger engines do 6k Hrs easily with recommended service intervals

 

[Bajansailor]

I know of a Yanmar 4JH in a Sun Odyssey 40 which is 10 years old now, and has got a bit over 6,000 hours on the clock - it had a hard life as a charter boat in the BVIs, with the engine being used for an hour or 2 every day to charge batteries when out on charter.
This engine has only ever had routine maintenance as far as I know (but it was carried out assiduously, according to the records provided by the charter company when my friend bought it) and still looks in good condition, with hardly any rust, and no oil leaks.
We are hoping that it will keep going for at least another 1,000 hours before needing any major work.

 

[mikehibb]

My ex charter 2001 Yanmar 3GM30F supposedly had over 8,000 hrs on the clock when I bought it two years ago.
This was obviously proved to be wrong as the hours run meter had been swapped for an old one and not recalibrated.

However resonable estimates of a couple of hours run morning and evening every day in commission puts the engine at well over 3,000hrs.

It starts first time, and no funny coloured smoke.
To tell the truth I feel that I do not push it enough, when on motor I usually have it running at 2500 rpm or so.
Each trip I tend to give it a little more throttle. It will be going for full service in a couple of weeks time.
The guy that I first went out on my boat with (local skipper and boat maintenance company owner) told me best thing for a Yanmar (or any marine diesel) is to give it plenty of throttle.

No oil leaks. very clean engine bay.

As Bajansailor says, expect 1000 hours (or more) out of it.

 

[nealeb]

there's also the question of the relative wear-rate when an engine is just being used to charge batteries. It will be slow to warm up of course, which can't be good, but is there any other bad news to balance the low stress regime of running at idle speed for hours at a time

Yes - lack of ring pressure (generated by gas pressure in the combustion chamber) means that the rings tend to polish the bore which then leads to blow-by, combustion gases get into the oil and contaminate it with corrosive by-products, and lead to general degradation. A more loaded engine generates more ring pressure which leads to better sealing, hence recommendation for cruising revs at around 20% below max (Yanmar figures, from memory) rather than too low a load. So runs a common explanation, anyway. I have to say that I tend to run my engine at lower speeds than that but I do try to avoid leaving it run at low revs for long periods (and especially running the engine just for battery charging).

 

[TheBoatman]

8000 hrs is not a problem for any diesel engine but it does depend on the type of usage. In my YC I have to "look after" our club boats and two of them have had Yanmar 3GM30's that have now been replaced with 3YM30's. The reason for replacement wasn't that they ran out of steam but because members contrived to drive the boat with no water (sea cock turned off) or even sink them.
The bottom line is - if it starts easliy, has no decernable smoke from the exhuast - its probably a good'n.

Peter.

 

[mortehoe]

I rebuilt my Yanmar 1GM10 three times .... because of ....

Overcranking which caused seawater backflow into the cylinder. This was eventually traced back to an everso slightly incorrectly installed Vetus exhaust system (The problem was nothing to do with Vetus, but the original 'professional' exhaust system installer) Cost of rebuilding 3 times ---- Don't ask because it cost more than both a new engine and exhaust system!

Now a Yanmar 3GM30 is essentially a compounded version of the single cylinder version. My 1GM10, now 20 years old, some 4,600 hours on the clock, totally abused and with 2 bent con_rods - but the oil changed every 100 hours ... has some very interesting wear facts:

Compression: 21 to 1 after new parts fitted (With bent con_rod it dropped to 14 to 1 .... but the engine still worked after much turning of the starter motor and much white smoke out of the exhaust!)
Cylinder wear - less than 0.001mm out of oval
Rings gap wear - No discernable difference
Valve sinkage - 0.012 mm after regrinding (still well within tolerance)
High pressure injector pump - serviced and rebuilt (inspite of E P Barrus saying that an injector pump is unservicable .... took it to a tractor specialist and we got the necessary parts from the USA via Bermuda!!!! ... and the whole cost was 1/2 the price of a Yanmar injector pump from the UK!!!! - YES you can import Yanmar spare parts into the UK and the price drop is well worth considering - It's up to you to work out your own importation route.)
Piston compression - 0.01mm = significant (caused by water backflow - nothing to do with engine wear)
Push Rod/Tappet shim wear - manufacturers specification

ETC.

Given that a 3GM30 approximates in most things to a 3 x 1GM10 from the wear data recorded (or lack of wear data) it would appear to me that any properly maintained Yanmar GM series engine should be capable of lasting at least 12,000 hours. NOTE WELL: You MUST change the OEM exhaust elbow at least every 5 years (500 hours). You might find it better to have a 316 S/S one made up for you with the injector point just before the rubber hose + you ought to clean the elbow out at least every 200 hours!

BTW, the USA standard for small marine diesels is a MINIMUM of 5,000 hours.

 

[Impaler]

Not a marine engine but I have a 1961 Fordson Super Major tractor. I use her weekly over the summer for grass topping and in the winter she sits idle. Oil & filter change annually. Starts first go every time, blows a bit of smoke on start but other than that runs like a dream. They don't make 'em like that any more!

 

[trapezeartist]

Thanks for all the contributions.

Conclusion: if this boat with 5300 engine hours is to be bought, the price must assume that it will need a new engine. Any engine life on the old one will be viewed as a bonus. This means, I guess, that the price must be £10k "below book", and that doesn't really allow for any other wear and tear on what must be a heavily used boat.

 

[Manuel]

My 4000 hour Yanmar runs like a sewing machine, no smoke, fumes, starts on the key in seconds even after weeks, no corrosion. It gets the oil changed on time and never hammered (typically 1800 RPM cruise which everyone says wrecks engines). Oil pressure on the correct line. If my life was at stake I would trust this engine to run continuously for 72 hours without missing a beat than a brand new engine just installed.

My guess is 10,000 to 15,000 hours if cared for. May need a full overhaul at 7,500. Just my guess. Same engine could rust after fifteen years and only 100 hours of course if not looked after.

 

[1bobt]

Hi
I had a Ford lorry which had a govenor on it that restrited its top speed to 56 MPH
This speed was aprox -35% 0f full revs. Running the engine at this speed did no damage
Why do people say that you have to work a diesel engine hard?

Cheers bobt