Good post........So if doing what my great grandfather said got my old Perkins to 20,000 trouble free hrs. I think I'll stick with that practice no matter what is said on this forum.
boatpoker;190462. When winding down for the night we did it slowly and never shut her down til' the temp had dropped about 30 degrees. [/QUOTE said:How can your operating temperature drop 30 degrees unless the motor is overheating or it has no thermostat?
How can your operating temperature drop 30 degrees unless the motor is overheating or it has no thermostat?
I do the same thing with the throttle solenoid activated so it won't start.
IMy boat (nor any other I have ever seen) will get up to recommended temperature at much less than 80% of recommended RPM.
My twin Perkins Sabre 225TIs (Cat 3056 if painted yellow) run at 173 degrees F rock steady between 900 to 1800 RPM. The full rated book RPM is 2500 which it can attain if called to do so.
Peter
I don't think there is a "one way is right" answer here. Look at commercial vehicle operations such as UPS delivery vans. These are light diesel engines which are started and stopped many times per day at every delivery point. They're constantly going from a 0 oil pressure state to operating pressure. Isn't this a wear factor? Plus they're started cold at least once per day? They seem to go hundreds of thousands of miles. As little as we use our boats in comparison, are the concerns about a cold start once or twice a month really warranted? I have my doubts.
Quite possibly, but as several have pointed out, this bears little relevance to the temp of the oil, .
In my case it does. Once warmed up the oil temps never drop below the coolant temp as there is a coolant to oil HX. This type of HX is common on many newer marine diesels. When shooting my pan with an IR gun the oil temps are pretty steady in the 185 to 195 degrees F range.
My ER is readily accessible via a separate door so when underway good ER inspections including about 12 IR points around each engine and through hulls occur on a routine basis.
But the issue is the increased wear encountered until all parts are up to full operating temp.
Although I understand what you are doing, that procedure doesn't tell you if you have sufficient compression for an actual start.Turning her over for a couple of reasonable bursts, but without actually firing provides a check on starter motor and battery function, and a quick circulation of oil around all moving parts, and hopefully lubricating/coating the cylinder walls with something to repel moist air, and leave different valves open or closed. That's it - aim achieved,
There are but maybe a handful of things that you DO have to do or NOT DO to get that far...and like RickB usually says...the rest is just urban myth,,,
Although I have no data to back up your statement, I tend to agree. We get all tangled up in our own underwear when posting about our hobby. Too much effort is spent on showing others just how much of an "old salt" we are.I'm thinking running a diesel under loaded or periods idling or starting and idling just to circulate fluids then shutting down is going to be near the bottom of a list of causes of diesel engine failure.
That "issue" is really just one more of the myths that are given wings in forums like this.
Unless an engine has been sitting unused for extended periods - and with modern lubricants, extended periods are getting longer and longer - there is usually a molecule or three of lube oil between the journals and the bearings while the engine is at rest.
As a journal begins to rotate several things happen, the oil pump delivers oil to the bearings and some of that oil is dragged by the journal to create a wedge of higher hydrodynamic pressure that lifts the journal further off the bearing surface. Once rotation occurs there is no contact and no wear as long as lube oil is present. The engine coolant and oil do not have to reach "normal operating temperature" before "increased wear" is pushed back under the bed.
The crankshaft is the highest loaded component but it also has the largest bearing area and receives oil flow first. The rest of the parts are exposed to relatively light loads and can (and do) survive thousands and thousands of starts with little wear.
The description above should explain why the manufacturer suggests not imposing high loads for a (usually short) period of time. Cold lube oil is more viscous than warm or hot lube oil, viscous oil resists flow and takes longer to reach the components at the end of the oil path. That is really all there is to it. If the engine is warm enough to start without a lot of aids and theatrics, oil flow will occur in very short order and you can drive away without concern that you are damaging your engine.
Oil doesn't have to be as hot as coolant, it just shouldn't be too cold to readily flow to all the parts that need it in sufficient volume to perform its tasks of lubing and cooling. Cool oil is good, cold oil doesn't pump well and its higher internal friction increases the time it takes to reach parts in the outback.
Once the oil wedge is established, wear stops. Temperature is a strawman thrown out by a few who do not fundamentally understand engine operation or construction. The sky does not fall on a cool engine, coolant does not have to reach or remain at some arbitrary level to hold off engine destruction, and oil does not have to reach or remain at its maximum operating temperature limit.
I’m glad I didn’t ask how to measure the mass of neutrinos. KJ
Well, I’d say the responses to the OP are quite informative, and quite varied.
So, if I read the info correctly it would appear that the choices are:
A. Don’t run the engines at all (doesn’t do them any good to run them,
doesn't hurt them not to be run either)
B. Run the engines for a short time with no load or optimum temp
C. Run the engines for a short time with load (80%)
D. Run the engines at operating temp for (?).
E. C & D
F. Buy an RV
G. None of the above
I’m glad I didn’t ask how to measure the mass of neutrinos. KJ