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

[Infomaniac]

OK have a custom built 522 Big block Chevy. Twin Turbo intercooled. Oil temp measured in the oil pan. Water temp stays just above 100 degrees. Jet boat, but oil temp climbs to over 300 degrees during high power runs and never goes below 250 degrees. It has one of the largest oil coolers available. 12 qt oil pan, well designed with windage tray. Oil pressure stays OK.

I'm curious: What design features of the engine will effect oil temp? Assuming that plumbing, oil cooler size, oil quantity etc are correct.

Royal Purple oil being used.

The major concern is oil breaking down. The oil is cooled before entering the engine. Do not know what the temp of the oil is there. Temp is measured in the pan. Even though the temp of the oil going into the engine is probably acceptable, the really hign temp in the pan is the concern of oil breaking down due to temp.

One final note, the turbochargers drain directly into the pan. The turbo housings are water cooled.

 

[Ryan00TJ]

I would toy with the idea of large dual coolers to try and get the temp down. At 300 degrees the oil is being really beat hard. Even 250 cruising is too high. The turbo's are probably what is causing the heat as under WOT conditions they produce massive amounts of heat. The fact they also drain directly into the pan will cause uch higher temps than what is entering the engine.

Sounds like a killer setup you have there! I can only imagine the sound of the 522!

What Temp Tstat? With those temps I would run at least a 50W as at 300degrees you'll need all the viscosity you can get.

 

[KBFXDLI]

You need WAY bigger oil cooler(s) or you have some type of restriction in your oil cooling system. I would add capacity and larger cooler plus you may wish to change cooler design because it sounds like you may have some thermal gradients in you oil cooler where the colder oil is sticking near the outer edges of the cooler surfaces while hot oil travels past it through the center of the lines. This happens on some air cooled motorcycle applications so you may need a cooler that has internal "fins or baffles " that force the hot & cold oil to mix as it's being pumped through the system. The only way to determine that is to measure oil temp in the entry and exit lines to see how efficient the cooler actually is. Good Luck!

 

[KBFXDLI]

If that doesn't work you make some dynamite french fries in that 12 QT pan. I think I'd be looking at 60w synthetic if you can get it.

 

[KBFXDLI]

You might try Redline 20w60HD

 

[Schmoe]

With that high of oil temperatures, at least the turbo's are getting a good coating of oil and the oil is pulling heat away from the bearings, which is a good thing but at the expense of the motor oil. Since you said that the turbo oil lines drain directly into the crankcase, it would seem that you need to cool that oil down somehow before it gets there. See if there is any way in measuring the temps coming off the turbos with a infrared thermometer. Would seem you oil pump is working fine if it pumps that much oil out of the turbos and into the crankcase with that much heat.
Maybe somehow circulate more lake water around the oil cooler quicker.

 

[SonnyJames]

"Jet boat, but oil temp climbs to over 300 degrees during high power runs and never goes below 250 degrees"

You gotta make sure that the engine is not running lean!!!!!!! Cant stress that enough. Sounds lean to me even tho there is a turbo involed.what do the plugs look like?Whats the timing??Is it carbed?

 

[1 FMF]

assuming that the engine is raw water cooled, it's getting a constant supply of cold water for cooling and you say engine water temp is always less than 140F, I would suspect a bad oil temp gauge first. What kind of oil temp guage? Can you back up that guage with a second measurement of some kind?

If the turbo oil drains directly into the pan, and you measure temp in the pan, is the turbo oil maybe flowing right over your temp sender, giving you somewhat of a false reading? And even though there's an oil cooler, that's after the pan and oil pump correct? So oil is cooled, but then run's thru the motor, gets hot, drains back to the pan and mixes with hot turbo oil

you say custom built, is there maybe a missing oil plug somewhere causing something to run hot from not enough oil pressure? What are your oil pressure #'s ?

 

[stingray69]

Depending on the Gen # of your BBC, is it possible that a relief valve in the pan rail is not allowing much oil to go thru the oil cooler system, and just sending it back to the pan?

If the cooler DOES read the 250* and 300* the you need to add another cooler.