300 + Degree Oil Temp HELP !!!!!!

[mechtech]

The oil gets most of it's heat from the piston bottoms, as it cools those very hot pieces.
Somehting sounds wrong with those 300 deg temps.
Like Mola said, maybe the sensor is picking up ambient block/pan heat.

 

[audi_guy]

quote:

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... Oil temp sensor is under the oil level of the oil pan. ...

the system is plumbed pan -- pump -- external filter -- external cooler -- engine -- parallel "T" to turbos -- pan.

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My vote is the turbos since if i'm reading the oil flow chart/temp sensor location correctly, the oil is going directly from the extremely hot, some times cherry red, turbos to the pan and the temp sensor. If the oil temp was measured before entering the turbos, you might see a good bit lower oil temp.

[ February 07, 2006, 02:21 PM: Message edited by: audi_guy ]

 

[JohnBrowning]

Well my money is on the turbo's heating the oil up right before it dumbs into the pan. Most automotive engines have airflow around the block and out the bottom. In a marine application you do not have the airflow around the block and turbo's so you get heat soak/saturation inside the engine compartment. If the coolers are not vented to fresh air with lots of CFM's then your coolers will still be fighting ambient heat soak even with good water flow. You also have to control how fast the water flows. Rember that the water has to have enough time in the exchanger to pick up some of the heat. You can actual hurt yourself if the water is flowing to fast this is why race cars use a steel plate with a small 3/8 inch hole in it in plase of a thermostat. If they run with no thermostat or plate at all often the vechile will over heat under raceing conditions. In a daily driver setup you normaly run into the oposite and the vechile will never come up to operateing temps.

If the oil pan is aluminum then it could be passing the engines heat directly into sensor as someone above mentioned.

You might consider improveing the oil volume and pressure through the engine and reworking the oil circuit if need be. You can also try shiming the bypass to reach a higher rateing of 95-125psi.SOme people bypass the bypass as well!

P.S. You might also try Redline 20W50!!

 

[MolaKule]

quote:

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The system is plumbed pan -- pump -- external filter -- external cooler -- engine -- parallel "T" to turbos -- pan.

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OK, here is the way I would plumb:

Sump -- pump -- external filter -- external cooler -- make split off or a another T for flow to engine and then to T for parallel Turbos.

Make sure external BP filter has plent of flow through it or bypasses properly.

 

[MolaKule]

"Make sure external BP filter has plent of flow through it or bypasses properly. "

Should have read:

Make sure external Full Flow filter has plenty of flow through it or bypasses properly.

The bottom line is you need to get the oil out of the sump and to the cooler as fast as possible, assuming the temp sensor is working and is positioned properly.

 

[Infomaniac]

WOW - Great suggestions. Very intellectual group as compared to a lot of discussion forums.

Where are the smilies?? LOL

I'm sure the temp is good as it enters the engine. The pressure does not drop off as would be expected due to extreme temps.

The major concern is..... If oil breaks down at 300 degrees, it does not matter what point in the lubrication process it reaches that temp. It is reaching it and will break down.

To answer a few others...
I have a Cougar v-drive tunnel boat. So the jet boat slam did not hurt. LOL

The engine block is a World Products Merlin III, the oil to the turbos has only flowed 12" through the block before exiting to the turbos, and has not performed any lubricating before exiting.

Yes it makes 940 HP at 5,800 RPM on 91 octane unleaded. it makes over 1,000 HP just over 6,000 RPM.

I did have a lubrication specialist feel that the water was not doing it's share of the cooling which is noted by just over 100 degree water temp.

 

[bulwnkl]

quote:

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The major concern is..... If oil breaks down at 300 degrees, it does not matter what point in the lubrication process it reaches that temp. It is reaching it and will break down.

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True (so long as you're reading the temp of the oil rather than outside heat soak as previously mentioned). So, how to address this? I guess you could turn down the boost.

I would be concerned with coking under/on the pistons and in the turbos and supply/drain lines.

I like the idea that the cooling system is not carrying its share of the heat load. So long as the oil coolers are of sufficient capacity to reject the heat, how about a higher-flow oil pump? Less time in contact with the heat source will allow less heat to get into each 'unit' of oil per trip through the engine. You might possibly need lower viscosity to go along with higher flow to make sure you still get designed gpm through the engine.

I sure hope you're using a very high-temp-capable oil!

 

[va3ux]

I'm still not sure or convinced that there really is an oil temp problem here at all. 300F oil in the pan of a big hard working marine engine with a turbo. I don't know - is that really too high ?

Does anybody know what the oil temp is in the pan of their car engine while they're flying down the highway at 70 mph in the summer ? Or idling in stop and go traffic when it's 85 or 90 outside ? Anyone ?

Oil vaporization and volatility temps for good oils are well in excess of 400F. Yet lots of people are topping up oil (when no leak is present) in between oil changes. Reason ? Because some is lost due to evaporation. Well if takes temps of around 400+ to vaporize oil, then you must have those temps (locally) in car engines. Otherwise you wouldn't be topping it up.

I don't know the hard answers here. I'm just thinking outloud. But with no data sitting here to say what a typical bulk oil temp should be in the pan of a given engine, 300F doesn't strike me as too high or too low.

And, is the thermo couple accurate ?

Feel free to enlighten me. If someone knows that 300F oil really is on the high end of normal, just say so.

For your consideration.

Phil

 

[MolaKule]

Yes, but aren't the turbos picking up a lot of conducted heat from the exhaust and housings - ball bearings not withstanding?

Another consideration is how long does the oil stay at 300 or 300+?

If these are momentary peaks and not sustained temps, it may not be a problem.

It does take time for any cooler/heat exchanger to reject heat.

Have the oil analyzed by Terry Dyson after a power run and see how much oxidation the oil has been subjected to.

 

[Wes Inskeep]

The temp would be as sustained as I would have fuel. I am running 260 at low cruise, and well over 300 on high performance passes. Keep in mind that a "pass" on this boat would be something in the neighborhood of 5 minutes at over 5500 RPM.

Seems warm to me, but another motor builder I respect greatly has mentioned that they measure temperature after the cooler, so who knows...

All I know is I cannot cool the turbo oil unless I go off the block, which is not that big a deal as Ron has suggested to me.

I think I will switch to off the block and see if that helps...

 

[Wes Inskeep]

For anyone interested, here are some links to pictures of the engine, oil system and rigging...

Trident Engine

 

[MolaKule]

Very nice plumbing and very professional.

However, if it were my engine, I would want to see what this temperature does to the oil (especially oxidation numbers) via expert oil analysis such as done by Terry Dyson. He has expertise in OB and inboard engines on Marine craft.

 

[Wes Inskeep]

How does one get a hold of Terry Dyson?

I am of the mind that all the analysis I need is on the temp gauge. I am trying to figure out how to lower the temp, while also finding out if the oil is getting too hot for longevity.

When I re-locate the oil temp probe, it may totally "solve the problem" in the sense that it will give me an acceptable reading. There are some great engine builders who put the sender post-cooler, so I certainly wouldn't be alone.

I am just curious as to whether or not a 280 pan temp is normal, or if anyone has bothered to look at the max temp oil gets to...

Thanks again folks...

 

[audi_guy]

quote:

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How does one get a hold of Terry Dyson?

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http://www.dysonanalysis.com/pages/1/index.htm

 

[Wes Inskeep]

Folks,

Thanks for all of the insight. You are hitting on major concerns of mine, and validating a lot of suspicions. A couple things to consider…

1) Turbos are water cooled. I will test using a pyrometer the exit temp of the oil drains on the turbos tomorrow when we test the boat again

2) Oil is plumbed off of the external filter, but prior to the cooler for the turbos. Turbo oil lines are -3 teflon hose. Turbos are essentially gravity drained using a -10 hose straight to the pan, right between crank journals.

3) Royal Purple pure synthetic racing oil straight 50W is the oil.

4) All external oil lines are -12 Stainless braid.

5) All cooling sources are external water that is pumped from the jet pumps to the various points. Cooling is as follows…

a. Engine cooling system
i. Pump, intercooler, exhaust manifolds, engine, turbos, out exhaust tailpipes

b. Oil cooling system
i. Pump, oil cooler, drive cooler, overboard discharge

A couple of items. I have had numerous high performance jet boats, and in each case I was shocked and frustrated by the amount of engine oil temperature when measured from the pan. So much so that I have incorrectly assumed many times that the gauge was wrong. Once, without a cooler on a N/A 509 Merlin I was running well into the 340 range and just assumed that wasn’t physically possible so discounted the readings. After checking the sender and gauge and adding a huge external cooler I managed to beat the temp all the way down to 280. A blown 468 in a jet yielded similar results and so did a nitrous injected 540 in a picklefork. My resolution for the other boats was easy… put in synthetic and don’t run it as hard for as long. This is not an option with this boat. It has to be able to run full throttle until the gas runs out. I can decide what full throttle is though…

My laser pyrometer verifies the gauge unfortunately. It is slightly cooler on the outside of the pan than it is reading, but not much. Maybe 5 degrees. I think we need to trust the gauge.

I have a tough time believing that I am the only one having these problems consistently. If I am reading from the wrong spot, so be it. If it doesn’t matter how hot the oil is in the pan, but more importantly what it is coming out of the cooler (going into the engine) than I can put a sender in and check it.

Another item of note is that the oil does not smell like it is cooking or bubbling out of the breathers. Frankly, except for the temp reading everything seems absolutely nominal.

Thanks for all of the advice. Ron has built one **** of a motor, I would like to make sure it stays together on my watch…


Wes

 

[Infomaniac]

Thanks Wes for that amount of detail.

I did not explain to these guys that I built the engine and you own the boat.

I think I see the problem. The turbo oil is never cooled.

What do you thnk?

 

[Wes Inskeep]

I dunno... It is getting cooled, just not directly. Eventually, it gets cooled because it is such a small percentage of the pumped oil.

I could try shifting it to a fitting post-cooler, but I really don't think that these water cooled turbos are getting that hot considering the sheer amount of oil being pumped through them. They are ball bearing turbos, and designed not to create a ton of heat.