Cranking Over After Oil Change

[Tellie]

Oil is the life blood of any engine. If ever there was a point to be anal, following proper factory recommended oil changes is it. Yanmar states 100 hours. Why fight the guys who create these engines? Comparing road diesels and marine diesels is apples and oranges. Different operations, run time, down time, loads and gear. Perspective, well taken care of OTR trucks can easily get 500K+ miles. If you just average 50 miles for each hour run time that's 10K hours run time. 10K hours on a well maintained marine diesel is not uncommon either. If you put 500 hours run time a year on your engine which is far more than the average boater that's 20 years. Even in 20 years 100 oil changes is a pitance. But being smarter than the guys who develop these engines is why being a marine diesel mechanic ain't a bad job.

[barnakiel]

And how do you add the new oil?

We add it thru the top oil cap - the oil goes on the engine first then to the sump - no dry starting! (I think).

I also turn the engine with the stop cable pulled and our engine seems to accept it no hiccups. Something wrong with your fuses or with the starter motor perhaps?

BTW Our engine can be turned by hand too - we decompress and simply pull on the flywheel.

b.

[um saudade]

To the original poster: If you can hear your engine rattle before it builds oil pressure you have some loose bearing shells. Every time you hear the pounding they are self-destructing. Normal bearing clearances will not make much noise at all when spinning with no oil pressure.

A quick trick to check out a used engine low end: Empty the filter housing or spin on a new filter, top off the oil level and crank it up listening carefully. If it demonstrably quiets down when the oil pressure hits the bearings, it has a worn low end.

Oil poured on top of a crankshaft does nothing for the bearings. Any bearing surface that does not have oil delivered under pressure inside the bearing shell is wearing at an extreme rate.

Cold start of any diesel causes most of the engine’s wear. (Cat taught me this in the 80’s when we put pre-lube pumps and pre-heaters on D399’s(V-16) and got them to run for up to 20,000 hours. Before the change we were lucky to get 8,000 hours out of an engine. I would add that the oil back then was not nearly as good as what is available now.

For the record these were generator sets that normally ran 24/7, two or three on line and one or two on standby so the hours added up fast, some ran close to 8000 hours in a year (at 58 gallons of #2 an hour for each genset !)

So fill the oil filter housing if possible. Crank the engine over on decompression to build pressure if possible. Change oil on a hot engine and start it back up as soon as you can.

If engine has not run for a few weeks, spin until the bearings have pressure before adding fuel. This is imperative for turbos. Over time the external oil line to the turbo drains back into the engine and it takes a few seconds to get oil back up to the turbo. If a turbo spools up fast and the bearings are dry, it’s toast!

I won’t get into the oil argument but I have had what most would call amazing results with regular motor oil. Make sure it is a diesel oil if going into a diesel and don’t run diesel oil in a gas engine (it is not better oil, it’s different oil, for a different job).

Um Saudade

[Mark Zarley]

After an oil change I restart my main eng at IDLE. Not looking for any high revs. Ditto for the genset, although it has a governor, I disable it by hitting the kill switch as soon as it first fires. This keeps the eng from running at the preset 3/4 throttle on start up, which is bad for any eng. If I could change one thing on generators, I would change the fuel system to one like on an air compressor. You could start the eng at lower RPM and let it run till it warmed up. Then pull out the throttle so it would run off the governor, then switch to power on. Of course this additional step might inconvience some, but for the good of my eng it would not be a problem for me. Those of you who are wondering about the logic for shutting down the genset when it first fires, I believe that more torque is transfered to the mains, rod and wrist bearings when an eng is actually firing. Taking away the fire while the oil pressure builds, I believe will extend my gensets life.

[sctpc]

Originally Posted by Tellie

Oil is the life blood of any engine. If ever there was a point to be anal, following proper factory recommended oil changes is it. Yanmar states 100 hours. Why fight the guys who create these engines?

Agree also you must ask yourself why EG. Bmw are 25000k service oil and say mazda are 5000k besides BMW being a better motor why would there be a 20000k difference?

[psneeld]

Originally Posted by sctpc

Agree also you must ask yourself why EG. Bmw are 25000k service oil and say mazda are 5000k besides BMW being a better motor why would there be a 20000k difference?

because there is no RIGHT answer....there is normal and there is HARD service. The old girlfriends Honda Pilot let the computer figure that out and would tell you based on driving conditions when to change the oil...not on just mileage.

[hellosailor]

tellie, don't dis the Chevy Vega. Chevy had a great idea, they copied the cylinder design from Porsche and used a 210F thermostat in the Vega in order to raise the cylinder wall quench temperature by 40F and get an increased gain in performance--just like Porsche.

Except Chevy forgot, Porsche owners will spend something on maintenance and buyers from GM's cheapest division and cheapest model aren't going to treat their cars the same. The Vega had no engine problems, it had owner abuse problems. With the Porsche cylinder design (IIRC it had something to do with a high-silicon alloy in the block, it wasn't just a temperature change) there was less tolerance for overheating, so if the owner slacked on the coolant or oil, poof! No engine.

On Yanmar's oil recommendations...Generally I'd take the advice of the manufacturer (excluding Westerbeke, who are contractor/assemblers) in the belief that they also engineered the product. But aren't Yanmar the same folks who zealously protect their franchisees--yes, franchisees--by prohibiting mail order parts sales? One might suggest that Yanmar really are trying to sell dealer service and gen-you-whine Yanmar oil and filters.
In the US there's a long history of what engine makers say, versus what oil makers say. The oil companies took Detroit into court (in the 60s?) over the question of whether you would void your factory vehicle warranty by not using the car dealer's oil. That got changed by the courts, you can use any oil you please now and unless the car maker can prove the oil caused an engine failure, they have to honor the warranty. Scare tactics, plain and simple.
Which is why oil makers also often will give you a written warranty against engine failure when you follow their protocols--not what the engine maker says.

Many things are best taken with a grain of salt.

"Hours" is just one possible rule of thumb. Feel the oil, smell the oil, if you think "hours" has arrived (of course your engine has a Hobbs meter, don't they all?) then send out an oil sample and get an objective report from a lab for $25. Mickey Mouse works better on the wrist than the dipstick.<G>

[Pete7]

Originally Posted by Dockhead

I change my oil fairly frequently -- three or four times a year, so usually less than 100 hours.

DH, do you really do 400 hrs a year on the engine? I suspect it's a lot less. If it's more like 200 hrs a year you could half the oil changes and still stay within the manufacturers recommendations. You need to record engine running hours in the log.

We manage about 100 hrs a year on the engine, but always change the oil and filter before winter sets in even if we haven't reached Volvos recommendation.

We did try semi synthetic one year because I had some left over from a car. Yacht engine became really difficult to start so went back to the cheapest supermarket dino oil (Wilkinsons) and much better starting.

Pete

[psneeld]

Originally Posted by Pete7

DH, do you really do 400 hrs a year on the engine? I suspect it's a lot less. If it's more like 200 hrs a year you could half the oil changes and still stay within the manufacturers recommendations. You need to record engine running hours in the log.

We manage about 100 hrs a year on the engine, but always change the oil and filter before winter sets in even if we haven't reached Volvos recommendation.

We did try semi synthetic one year because I had some left over from a car. Yacht engine became really difficult to start so went back to the cheapest supermarket dino oil (Wilkinsons) and much better starting.

Pete

That I don't believe unless you bought cheaper dino with even a LOWER viscosity rating....(10W versus 15W or something like that)...especially if it's a diesel

[SuenosAzules]

I agree with Astrid on this. There will be enough residual oil in the engine to protect the internal parts at cold start up.