Brief Crank during winter

Guys, read the whole text!!!!
I said at idle, didn't I???
I really don't know why I am bothering here,
Please, first learn the basics, how engine works, how cooling works, history of engines etc...
Did you ever hear of engines that were water cooled with free circulation, without water pump, radiator or anything that your engines have...
FYI I am a trained mechanics with skills and license in some diesel engines and gas turbines...
Maybe this sounds funny to you, but learn before you say something you don't have a clue of...


Goran
 
gmurtic said:
Guys, read the whole text!!!!
I said at idle, didn't I???
I really don't know why I am bothering here,
Please, first learn the basics, how engine works, how cooling works, history of engines etc...
Did you ever hear of engines that were water cooled with free circulation, without water pump, radiator or anything that your engines have...
FYI I am a trained mechanics with skills and license in some diesel engines and gas turbines...
Maybe this sounds funny to you, but learn before you say something you don't have a clue of...

Goran
Click to expand...

I received an email from Nigeria this morning that is far more convincing than you.
 
OK... let me go re-read what you said before....


gmurtic said:
And now physics basic: As long as there is coolant in the engine, you cannot overheat your engine at idle!
Why??
You can heat fluid as much as you want, but it cannot get to more than boiling temperature as long as it is fluid and not steam!
Goran
Click to expand...


Yep... that sounds really stupid. Let me rephrase your last statement there:

"You can heat fluid as much as you want, but it will not boil if it is not boiling".

The bitch is... the pressure will increase with the heat being added which keeps it from boiling (turning to steam). Then when the radiator cap blows off at 35 psi and hoses/clamps fail and the pressure goes down.... boom... slow overheating becomes quick overheating.

Your physics (or thermodynamics in this case) explanation is just not true.

An engine's ability to properly dissipate heat at idle as fast as it is being added from combustion/friction without the raw water circuit would be engine specific.

Telling people they can run their engines at idle without the primary heat dissipating system and never worry about over heating is just silly and irresponsible. Granted anyone can run a cold engine for a few minutes without any damage from overheating... but your statement goes beyond that explaining the reason is because the water doesn't turn to steam. That's BS.
 
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Four Suns said:
OK... let me go re-read what you said before....

Yep... that sounds really stupid. Let me rephrase your last statement there:

"You can heat fluid as much as you want, but it will not boil if it is not boiling".

The bitch is... the pressure will increase with the heat being added which keeps it from boiling (turning to steam). Then when the radiator cap blows off at 35 psi and hoses/clamps fail and the pressure goes down.... boom... slow overheating becomes quick overheating.

Your physics (or thermodynamics in this case) explanation is just not true.

An engine's ability to dissipate heat at idle as fast as it is being added without the raw water circuit would be engine specific and has nothing to do with water vapor pressure.

Telling people they can run their engines at idle without the primary heat dissipating system and never worry about over heating is just silly and irresponsible.

Things like this remind me why I do a lot of my own engine work.
Click to expand...

I don't know, Gary. Your explanation sounds hokey to me. I think this guy is onto something.
 
Well... I just found the explanation of why the engine doesn't overheat funny not the issue of if it would or not.... I know when I smoked my starboard impeller last summer, I brought the engine to idle and then temp cooled down at first and then the temp kept rising until I shut the engine down. I would argue that the engine at that point couldn't dissipate the BTU's fast enough generated by 1.5 gph of diesel fuel burning (idle) without the raw water system removing some of the heat. Of course the engines were heated up and the thermostats were open by then. Running an engine from a cold temperature won't open the thermostats for about 10-15 minutes on my engines so having an impeller removed and the raw water cooling shut off won't hurt it. However, it's because the engine is warming up and there is a lot of iron to absorb the heat and it doesn't need the raw water at that point. Letting it sit there at idle for an hour with no raw water is something I would never do.... But that's not what the original question or post was about. I just saw the response of "it can never overheat because the water doesn't turn to steam" silly.

Which brings up another point... NEVER EVER run the engines with the impeller installed and the sea cocks closed... Take the dang impeller out for the winter if you are not going to be using the boat.
 
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Just to re-focus a bit... The question had to do with a brief crank of the engine, not starting the engine. I belive that the original post was asking about just moving parts enough so that they did not sit in the same place all winter. In this case cooling would not be an issue as the engine would turn less than 1 revolution.

As I see it this is more a question of lubrication. I am under the impression that there is a tremendous amount of wear before oil pressure builds up. That first crank causes metal on metal without much lubrication.

I'm with Gary - take the impeller out for the winter and let the metal beasts sleep for til spring.
 
I follow what Goran is saying .........as long as you watch the temperature gauge to see when the engine reaches the thermostat opening point then shut it down, there theoretically shouldn't be a problem with hot spots in the engine. But, that doesn't address hot spots in the sea water cooled exhaust system castings like risers and manifolds. Nor does it address running a sea water pump with no water in it.

The other problem with this whole idea of a brief crank during winter, on diesel engines in particular, is the cranking speed of the starting system. You are not likely to just bump the starter if your batteries are hot. No longer than a winter layup is, if you must turn the engine to change spring pressures, etc, then do it by hand with wrench on the crankshaft pully.

From a practical standpoint, I think the idea of a brief crank during winter is a not worth the effort. Engines are durable enough to sit idle for the winter, and you may do more harm than good if you try to run them or even crank without starting.

I bought a dump truck several years ago that was turned over in a dirt pit. It had a 3208 Caterpillar engine and layed on its side for a year, then sat in a field for 5 years after it was pulled out of the pit. I bought the truck, changed the fuel filters, drained the water out of the tanks, changed the oil, put in fresh batteries and the engine started and ran smoothly after turning about 1 revolution with the starter. The engine sat idle summer and winter for 6 total years with no damage..........I can't get excited about "a brief crank during winter"
 
I think beside the discussion do or don't crank, changing with fresh oil just before the winter stop is the best you can do.

Run engine again for about 5 minutes to distribute a protective film of the clean oil to act as a rust preventive during storage.

Same for transmission.

I think if you do this you don't need to crank.
The modern oil has so many protective dopes, that the rust and corrosion protection is perfect. (with good oil)

My 2 euro cents :smt001

Peter.
 
What Frank said. Running a marine inboard that has a wet type of exhaust system without raw water is a boat about to become a pyre.

gmurtic said:
Guys, read the whole text!!!!

FYI I am a trained mechanics with skills and license in some diesel engines and gas turbines...
Maybe this sounds funny to you, but learn before you say something you don't have a clue of...


Goran
Click to expand...

You may wish to keep in mind that, on the Internet, you don't know with whom you are corresponding. The fellow on the other end could be a 12 year old kid, a bum using the computer in a public library, or the head engineer of Caterpillar. On this forum, you could be arguing with a rocket engineer (former) or with a dopey kid. The key is knowing the difference.

Best regards,
Frank C
 
I didn't say that!
 
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