Ceejay
Well-Known Member
and the correct running temperature, so worth fitting a temperature gauge and changing the thermostat if the engine starts to run cool.
CJ
disposable engines???
- Thread starter fatsailorgit
- Start date
and the correct running temperature, so worth fitting a temperature gauge and changing the thermostat if the engine starts to run cool.
CJ
Dockhead
Well-Known Member
I also run mine at 2400 - 2500 most times, although it is rated max revs at 3800 and max continuous at 3700. It runs sweetly, although it does smoke a lot when cold (I'm going to change the injectors to try to cure that).
I change the oil and filter usually at 50 -- 75 hours, so two or three times a season. So often because (1) it's easy and relatively cheap; and (2) sucking the old oil out the dipstick tube, I only get 5 litres or a bit more than half the oil capacity out, so I figure you really need to change it more often since so much old oil remains after the change.
I have about 1100 hours on at the moment (so about 300 in a year and half) and certainly hope to get many more out of her.
nimbusgb
Well-Known Member
On the subject of longevity ...
My boat engine is 26 seasons old and still works fine.
No way will my car engine last 25 years without major surgery.
My boat engine is 26 seasons old and still works fine.
No way will my car engine last 25 years without major surgery.
Dockhead
Well-Known Member
I know that what you say is the conventional wisdom, but I for one don't believe for a minute that there is any harm at all in running a diesel engine at 40% of its rated power, or even 20% of the rated power, provided the operating temperture is correct and the engine was properly run in.
This guy, a denizen of this forum, seems to agree:
http://coxengineering.co.uk/bore.aspx
Tranona
Well-Known Member
Therein lies the rub! The original example had only run 250 hours and was never "run in". Modern engines are built to very close tolerances. The manufacturers' advice is to run small diesels hard - Yanmar recommend 75% power. I don't think glazed bores is particularly an issue in a correctly used engine but can be in an abused engine - ie one used for short periods at low revs.
Ubergeekian
Well-Known Member
My Yanmar 1GM10 was made in 1986 and will be getting a new head fitted this weekend. My Citroen DS engine was made in 1975, has never had major work done, runs perfectly and uses no observable amounts of oil whatsoever.
EuanMcKenzie
Well-Known Member
my boat engine is from 1972 and has circa 400 hours on it
It rarely works hard as its oversized for the boat but its still fine
It is based on a slow revving peugeot indenor diesel and suspect it wasn't built to very tight tolerances.
My mate is a tractor engineer and quotes 10000 hours plus as normal on engines that chug a way pulling ploughs in low gears all day.
The mineral oil probably ensured it wore a bit to let it run in properly.
Suspect this 250 hours is a one off specific to that engine
Servicing, running in and using the right lubricants are the issue. thats it!
My engine will corrode to bits and become uneconomical to repair. it won't wear out in my lifetime.
It rarely works hard as its oversized for the boat but its still fine
It is based on a slow revving peugeot indenor diesel and suspect it wasn't built to very tight tolerances.
My mate is a tractor engineer and quotes 10000 hours plus as normal on engines that chug a way pulling ploughs in low gears all day.
The mineral oil probably ensured it wore a bit to let it run in properly.
Suspect this 250 hours is a one off specific to that engine
Servicing, running in and using the right lubricants are the issue. thats it!
My engine will corrode to bits and become uneconomical to repair. it won't wear out in my lifetime.
Avocet
Well-Known Member
I worked for a car manufacturer around the time fully synthetic engine oils started to come out. We went through a spate of huge oil consumption and glazed bores (petrol engines). The oil manufacturer told us to use their cheapest nastiest mineral oil for the first 1000 miles and THEN switch to the fully-synthetic for exactly the reasons stated above. it worked like a charm - the problem stopped overnight.
grumpy_o_g
Well-Known Member
I agree that's a killer for the engines but their problem is that they're air-cooled so, when you're hauling a glider up to 2,000' or so, you've got a higher than normal load on the engine AND a lower airspeed so less airflow over the heads. Then you risk totally k*****ing it as you say by throwing into the fastest descent you can manage with the throttle closed which risks thermal shock on the heads - they don't wear out so much as go bang usually. The old Lycomings and Continentals were very unstressed and uncomplicated - the aviation equivalent of John Deeres and Gardiners I guess.
You shouldn't see cooling issues to the same extent with a water-cooled engine in an enclosed engine bay/room. I suspect that a modern Rotax or similar could well struggle in glider tug, especially if you threw in a salt-water environment - similar to the way that the modern high-ouput/low weight diesels seem to in boats.
Just speculation on my part though.
vyv_cox
Well-Known Member
My website needs some updating, which it is getting thanks to my accident-enforced time at the keyboard. I have been doing quite a lot of research into the glazing problem and my main conclusion is that cylinder temperature is probably the most important factor. There is a close parallel in reciprocating compressors, which I have worked on extensively for the past 40 years.
If the bore is cold, certain components of the combustion gases are likely to condense on it. In time, and as the temperature increases, this condensate will form the lacquer that becomes glazing. Running an engine at low revs, or even at tickover/battery charging speed, is unlikely to do much harm if done hot. Which, of course, is rarely what is done when running the engine solely to charge batteries.
Ubergeekian
Well-Known Member
Worse still, my Pirat had a maximum aerotow speed of only 67kt, so tuggies used to ave to take me up with the CHT needles just brushing the red.
A Swedish group converted a Pawnee to use a Volvo car engine with toothed belt reduction to the prop. By all accounts it was excellent - fast climbs, much lower fuel consumption, no CHT issues - but I think regulatory issues stopped it being repeated. They reckoned the engine would last as long as a Lycoming between overhauls, and that it was cheaper just to replace the Volvo engine with a new one than to rebuild the Lycoming ...
westernman
Well-Known Member
I think there is a small Austrian built plane which uses twin Mercedes TDI diesels of about 75hp each. They are also simply replaced at 2500 hours or so instead of an expensive overhaul required for Rotax'es etc.
Avocet
Well-Known Member
How cold is "cold"? My engine is raw water cooled and the thermostat opens at a ridiculously low temperature (40 or 50 C, I think!) - presumably to try and limit the ravages of hot salt water on the iron head. I've never had a problem with a glazed bore.
billcowan
Well-Known Member
I see that engine threads attract almost as many glazed bores as ones about anchors,
Maybe we should drift this thread and get the best of both combined:
what is the best engine block to use as a mooring?
Maybe we should drift this thread and get the best of both combined:
what is the best engine block to use as a mooring?
Tranona
Well-Known Member
Stuart Turner - not many about these days though!
vyv_cox
Well-Known Member
Cold means cold, i.e. seawater temperature. It would seem that engines run under load from start warm up more quickly, largely avoiding the problem.
Although I now have an indirectly cooled engine, my previous three were raw water cooled. None of them glazed either. New engines are more prone to the problem than well-used ones because the deposits adhere better to honed, non run-in bores.
EuanMcKenzie
Well-Known Member
are the bores glazed on your anchor?