running the engine to charge the batteries

[a64pilot]

If you look at almost all other engines you will find the oil is cooled by coolant, now if the oil is cooler than the coolant how can it be cooled with coolant?

[a64pilot]

Now I know the DMax Diesel and it’s a modern Diesel so I tend to go there first.
But this explains oil cooling and use of oil to cool pistons etc pretty well. It also explains the oil cooler and has pictures Now I believe he’s running a pretty hopped up motor to see those oil temps, but still the explanation is good.
http://www.maxxtorque.com/2008/01/du...ng-part-1.html

[S/V Adeline]

Originally Posted by a64pilot

If you look at almost all other engines you will find the oil is cooled by coolant, now if the oil is cooler than the coolant how can it be cooled with coolant?

Once the engine is at operating temperature the oil, coolant, and block surrounding the pistons are pretty much similar temps (block closest to combustion will be hotter). In my personal car it is 189-193 at the head, when moving interstate speed, 203 at idle setting still.
All heat is transferred out of the engine block via the coolant, which becomes cooler in the heat exchanger or radiator. Heat radiates into the raw water or ambient air, depending on setup.

The oil in the sump will be cooler than the oil running through the cylinder walls, head, and draining back down, but the difference is negligible after operating temp is reached.
In conventional designs, there is no oil cooler, the heat is transferred through the block to the coolant.

[skipperpete]

Originally Posted by a64pilot

Well just as a first glance you have a few things incorrect, first the combustion chamber in a DI Diesel is in the piston, the piston is oil cooled mostly that is why many have oil jets spraying on the bottom of the piston, and if it’s an IDI motor, the pre-combustion chamber is in the head, the heat is generated and absorbed in the head. A large amount of the heat that the head picks up is from the exhaust, that flows out of the head of course.
If you have ever been around aircraft piston engines you’ll know that there are two temperatures that are monitored, cylinder head and oil temp.
Secondly, yes cavitation does exist and is a problem with wet liner Diesels, but the source of the cavitation is from vibration of the liners, it’s not at all due to temperature and anything boiling, in fact if there is any boiling of the coolant at all, anywhere in the engine, ever, you have a serious problem that needs addressing.
This explains cylinder wall cavitation, the Ford small truck Diesel is particularly susceptible to it, and monitoring coolant PH and keeping it within specs seems to greatly reduce it.
https://www.enginebuildermag.com/201...sel-cylinders/

Then onto the reverse flow cooling, it’s true the old Dinosaur Diesels are not reverse flow, but I’ll bet you’ll see it more and more, and aluminum cylinder heads too, my 01 Duramax was reverse flow and had aluminum heads.
This explains reverse flow cooling.
http://www.corvetteactioncenter.com/...ystem-526.html


Then just out of curiosity what is it that you think cools the crankshaft and camshaft, there is significant friction, and friction means heat.

Perfectly explained A64pilot especially the cavitation on liners. Incidentally it was common to have the cylinder block bolted to the crankcase as a seperate unit , Gardner engines had it from day one and the very hi tech Steyr engines use this arrangement on their current marine engines.

[a64pilot]

Originally Posted by S/V Adeline

In conventional designs, there is no oil cooler, the heat is transferred through the block to the coolant.

That is correct and I can almost guarantee you that if you measure oil temp at highway speed, not pulling its guts out but a regular say 2000 RPM cruise, you will find oil temps are quite a bit higher than coolant temps.

https://www.hotrod.com/articles/engine-oil-temperature/

Probably take awhile to find it, but GM targets between 220 and 240f for oil under normal operations and of course for the higher performance engines they cool the oil with 195f or so coolant.
My Wife’s CTS-V reports many temps to include oil temps which often runs right at 220 or so if we are just cruising around, put it on a track and it will run much higher of course.

My boats oil filter seems to be about 160ish or so if I remember right, which to me sounds too low and I don’t understand why Yanmar would want it that low?
Now the filter is sump temp and that is going to be lower than oil coming off the cam and crank and draining off the head but still 160 seems awfully low.

If you get the software there is an enormous amount of data on an OBD II equipped car, my truck knew oil temp, air temp, barometric pressure, of course mass air flow, fuel temp, oil temp, percent throttle, boost pressure intake air temp, coolant temp, transmission temp, and on and on.

I’m sure the new common rail motors you can pull all that data, if the software is available, I know it was for my Mercury Verado. In fact their Merc monitor displayed all that and more like water coolant pressure.

[a64pilot]

Originally Posted by skipperpete

Perfectly explained A64pilot especially the cavitation on liners. Incidentally it was common to have the cylinder block bolted to the crankcase as a seperate unit , Gardner engines had it from day one and the very hi tech Steyr engines use this arrangement on their current marine engines.

I know many big motors are separate pieces as casting one huge piece just doesn’t make sense.
But if memory serves the Porsche 928 aluminum V8 the block was in many pieces and actually stacked together, I assume Porsche couldn’t cast a large piece.
Now I have not pulled a 928 motor so that may be incorrect.
Although I believe it was an aluminum cylinder motor like the Chevrolet Vega was.

[CassidyNZ]

Originally Posted by S/V Adeline

I can't believe this argument is actually happening.
It's called a cylinder block because it's a block containing the cylinders...
It actually has cylinders in it, the proper term as detailed by the manufacturer is cylinder block.
What is referred to as an engine block contains both cylinders and crankcase areas.
Regardless what you call it, the cylinders are water cooled.
Even in one piece blocks, the coolant is not below the cylinder level. Everything below that level is usually cooler than combustion level and higher.

Hallelujah. Finally a ray of hope. I’m not the only one who understands that coolant is called coolant for a reason.

Honestly, if this discussion is going to include comments like “the coolant flows around cylinder liner but not around the inside of the block” then there’s not much to add. How many engines have these experts seen that has a thermostat controlling oil temperature? C’mon people, this is not rocket science.

The fact that the “boiling” as I’ve called to simplify the discussion, is caused by vibration of the liner does not detract from the fact that it is the coolant that causes cavitation and the temperatures involved are very high. Way higher than oil temp for certain.

The reason why coolant is cooler than the oil is because of the volume in the cooling system and the far superior heat exchanging that is used to cool the coolant. Cold raw water cools the coolant, the coolant cools the oil. As I said in my first post on this subject - oil is not the primary source of cooling.

Let me just say before withdrawing, that the Yanmar engine operation manual list as chapter 5 in the Contents as “Fuel oil, lube oil and cooling water”. Funny that, no mention of ”cooling oil”.

Maybe as a final, final comment, why is it that 99% of IC engined cars and trucks on the planet, gasoline or diesel, have a radiator to cool water, some have another small air-to-oil heat exchanger to cool the transmission oil but very very few, if any, have an engine oil cooler?

I’m done here.

[newhaul]

Oil cooled marine engine .

Wankel model 64

[transmitterdan]

Whether you want to believe it or not lube oil is also a coolant. It is a good coolant in much higher temp spaces where water based coolants would not work.

Likewise, fuel oil also lubricates and cools some parts.

Newhaul was just pointing out that the main block of some engines do not have water courses. Sheesh....

[a64pilot]

Originally Posted by CassidyNZ

How many engines have these experts seen that has a thermostat controlling oil temperature? C’mon people, this is not rocket science.

Every aircraft engine that I have ever worked on.

But back to how do you suppose all the engine internals are cooled if not by the oil?

[newhaul]

Originally Posted by CassidyNZ

Hallelujah. Finally a ray of hope. I’m not the only one who understands that coolant is called coolant for a reason.

Honestly, if this discussion is going to include comments like “the coolant flows around cylinder liner but not around the inside of the block” then there’s not much to add. How many engines have these experts seen that has a thermostat controlling oil temperature? C’mon people, this is not rocket science.

.

almost all of them have an engine oil thermostat .


Explain this Google of oil thermostats

https://www.google.com/search?q=engi...w=1024&bih=768
And this screen grab

The second is out of the yanmar manual of the oil cooler assembly .
Part #64 is the oil cooler thermostat.
https://www.yanmarshop.com/catalogue...-oil-cooler-lu

[S/V Adeline]

Things I have learned on CF.
2 years in college studying automotive technology was wasted. Untold number of FordStar classes were lost time. Countless hours lost in GM technical training. If I could only get my time back from Dodge as it was in error too. Even my time at Mazda was ill spent. 16 years, 14 of which a Master Certified ASE focused heavy engine and transmission repair and all those manufacturers had it wrong. They think coolant cools the engine and oil lubricates it.

I wish I could fall back on the specialized 6, 12, 24v training which led to me being *the* go-to for wiring and electrical diagnostics in three dealerships but I recently learned in another CF thread all my electrical training was wrong too.

Why did I waste my life so...?

While it's true oil can cool metal, it is primarily a lubricant. Engines with oil thermostats require oil that needs to be hotter to work properly in that engine. The purpose of a thermostat is to increase temperature, they do not help in cooling.

I challenge anyone who believes oil keeps their engine cool to drain the coolant, replace it with oil, and let us know how many miles they get.

My apologies to the OP for my part of drifting the thread

[Ballsnall]

Originally Posted by S/V Adeline

Things I have learned on CF.

Why did I waste my life so...?

Hahaha, you must be gutted to find out you can learn anything from an anonymous stranger on a forum.

[newhaul]

Originally Posted by S/V Adeline

While it's true oil can cool metal, it is primarily a lubricant. Engines with oil thermostats require oil that needs to be hotter to work properly in that engine. The purpose of a thermostat is to increase temperature, they do not help in cooling.

Categorically incorrect. Water/ antifreeze, oil, and trans fluids use thermistats to maintain them in the optimum oprrational range either allowing less fluid to flow to warm it up or allowing more to flow to cool it down to maintain an optimum temperature.

As to a big diesel engine i can drain all of the water out of it and it will sit all day idling in my yard. Also if i instead of using water i use the appropriate weight of oil it will run just fine .
All of which has naught to do with what will happen to running a marine diesel to charge batteries . And that is nothing will happen . DONT PANIC.

[transmitterdan]

What has you so upset? Each fluid is optimized for a specific purpose. Oil and water are both lubricants and heat transfer fluids in an engine. Water keeps the pump seals lubricated. Try running the pump without water? It will fail prematurely.

Oil can withstand higher temps so it is a good coolant for things hotter than water can handle. It is also a lubricant as we all know.

There are tons of things cooled with oil instead of water. For example, power distribution transformers are cooled with oil and not water.