Starting Engines

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The boat in my avatar had 8,000 hours on her when we bought it. We put another 12,000 hours on the Perkins HT 6-354 for a total of 20,000 hours over 16 years when we rebuilt her. Reason for rebuild - a tiny bit of slap in one piston and an impending trip south.
In 12,000hrs we had three failures and all were to do with the raw water pump.
There were only three mechanics who worked on this boat prior to my purchase and all of them are friends. The first was the resident mechanic at the Royal Canadian Yacht Club, the second was his son who took over that RCYC position when his father retired. The third mechanic has been a close friend for decades, All three of them agree with my practice.

She was never run for more than about 3 minutes without a load (while we untied the lines). We ran her slowly up to 1600 RPM for about ten minutes to bring her up to temperature then ran her at whatever was comfortable. When winding down for the night we did it slowly and never shut her down til' the temp had dropped about 30 degrees. I learned this from a ninety three year old great grand father who ran Kelvins, Gardners and Bolinders (look that one up its a fascinating engine).

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.
 
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boatpoker said:
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.
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Good post........:popcorn:
 
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?
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sunchaser said:
How can your operating temperature drop 30 degrees unless the motor is overheating or it has no thermostat?
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I think thats a big part of this discussion. I can run all day at 1300rpm and never get over 150 degrees. I can't hit the desired 180 unless I am running at 1600RPM. Wgen I slow down to 1300RPM the termperature drops quickly, then entering the marina at 1000RPM it drops some more. BY the time I am tied up (or hook down) I'm down to 150 degrees.
My boat (nor any other I have ever seen) will get up to recommended temperature at much less than 80% of recommended RPM.
 
boatpoker said:
My boat (nor any other I have ever seen) will get up to recommended temperature at much less than 80% of recommended RPM.
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Mine does! :popcorn:
 
Mine does it after a few minutes at 1000rpm in neutral at the float.
 
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During periods of non-use I like to crank the engine twice for two 10 second periods every 30 days. Distributes lube oil, exercises rings and oil seals.
__________________
Eric (Manyboats)

boatpoker said:
I do the same thing with the throttle solenoid activated so it won't start.
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RickB said…
….There is more to it than just temperature though which begs the question "what are you hoping to achieve by idling at the dock in neutral?"

To me, having heard all these old chestnut ideas bounced back and forth for years regarding this issue, this one is the only one which makes any logical sense to me. What does running them up to operating temp really achieve, when all the wear is during the cold start, then the warm up from cold? It's not even an adequate test of hose integrity. It seems to me logical then to minimise running the engine cold for any longer than necessary unless you are indeed going to go out, in which case under reasonable load, the cold/warm period is reduced to a practical minimum. Ok, having said that what else are we hoping to achieve by turning the engine over at all..? In my view, just what Eric (Manyboats) & Boatpoker are achieving, and which I suspect is what Rick is implying, albeit indirectly, and this is what I now usually do. 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, minimal cold running, therefore minimal wear, other than on the starter motor, which is a lot cheaper to recondition, and is underused in the main anyway as moving parts go. Other than proper winterising in those parts that justify it, I have never heard a really logical argument against the above, but am always ready to listen.
 
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My JD4045 heats up to "operating" temperature (coolant water-wise) after about 10 to 15 minutes at about 40% between idle and maximum RPM (1400 RPM warm-up vs. 850 idle and 2400 WOT RPM), after about 5 minutes at 850-1000 RPM while untying and moving through the marina.
 
boatpoker said:
IMy boat (nor any other I have ever seen) will get up to recommended temperature at much less than 80% of recommended RPM.
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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.
 
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sunchaser said:
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.
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Quite possibly, but as several have pointed out, this bears little relevance to the temp of the oil, which is what needs to be at at least near normal operating temp to reduce wear. That is why many of us dispute the worth of just running at fast idle at the berth, even with mild load on it. It still must result in a full cycle of cold start/warm up wear occurring. That's the aspect that concerns me.
 
My Perkins 6.354's used to run 140 degrees until they were under load and run up to at least 1500 rpm's. Some years ago I changed the coolant and decided to change the thermostats on both engines at the same time. Since the change both engines warm to 180 degrees at anything over a dead idle. I'm assuming it must have had something to do with the old OEM thermostats.
P.S. After running your engine up to operating temp, put your hands around your lube oil filter or shoot it with your IR gun. That will tell you if your oil is getting hot.

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.
 
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I won't start the engine unless it will be run under load for a significant length of time. Believe this is best for the engine: minimizing engine wear. Don't see the benefit in just stirring up cold lubrication.
 
Edelweiss said:

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.
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I hear what you're saying Ed, but those are what we call 'hot miles', so in many ways the same as taxis. They do start and stop a lot, but they are still hot. Otherwise that would be a bad aspect of these modern cars where the engines are designed to stop at the traffic lights, then restart each time you take off. If that increased wear appreciably that would be a big turn off, but apparently does not, because they are not 'cold starts'.
 
Peter B said:
Quite possibly, but as several have pointed out, this bears little relevance to the temp of the oil, .
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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.
 
sunchaser said:
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.
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I have no trouble believing that Sunchaser, my oil coolers flow through a coolant heat exchanger as well. But the issue is the increased wear encountered until all parts are up to full operating temp. So arguably, coming back to the delivery van or taxi comparison, you put as much wear on just running her up to temp at the slip as you would doing a full day's cruise. That's the thing in this whole discussion, is it not..?
 
Peter B said:
But the issue is the increased wear encountered until all parts are up to full operating temp.
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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.
 
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ya gotta love the "my father and grandfather did it that way...so it's my way too"...hey if it works for you.... great!!!

But what about the guy whose grandfather and father did it the other way or even another way and their engines lasted just as long? There's plenty of those stories too.

The point is whether you DO something or DON"T do something doesn't mean you won't get 20,000 hours out of a Lehman or a Perkins...

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,,,

If this was such a big deal...I'm sure there would be a lot more consistency in manuals and writings about what "load" or "loads" to/not run your engine at...there isn't...just no max power till operation temp is achieved seems to be the only universal one.
 
>The crankshaft is the highest loaded component but it also has the largest bearing area and receives oil flow first.<

Perhaps in a modern engine with a roller cam lifter ,

but most 30-50 year old antiques have flat tappets , which are the highest loads..
 
Peter B said:
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,
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Although I understand what you are doing, that procedure doesn't tell you if you have sufficient compression for an actual start.
 
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.
 
psneeld said:
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,,,
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I'm gonna go down right now and run my cold motors against the dock and change my oil.

I know it'll cut the life in half, but I'm a rebel. :)
 
Steve said:
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.
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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.

Me! I love the photo posts on cruises to places I've never been. Since my long distance cruising days are over, I can cruise vicariously with those that are out there cheating death, daily. :blush:
 
SH II you are totally correct! Thanks for a great post.
 
RickB said:
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.
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Rick, that was beautiful....I think I got a tear!!!!
 
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
 
KJ said:
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
Click to expand...

I think you missed an important one...

Run the engines under ANY load you choose as long as the engine warms up to wherever it will stabilize....

That is what the engine would want if not tied to the dock...if concerned...it's really hard to drive all moisture out of oil unless running really hard but moisture usually isn't a problem unless you are letting a lot of condensation form in the engine anyhow...

.....and wear isn't usually an issue or certainly not that great as RickB pointed out...

As been said...if there's a chance of really "dry starts" when it comes to oil...a pre-luber is your best friend but again the chances of the engine wearing out from 5-6 relatively dry starts a year over it's life isn't going to really make a difference in the life of the ownership of most boaters engines.

They either cook them by missing an important issue...or a catastrophic failure occurs that probably didn't come from dry starts or running under load at lower temps and loads.
 
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