What are your thoughts on oil temps in a turbo motor under towing conditions....... the temp probe will be in the pan....
Conventional oil -----
Synthetic oil ------
Conventional oil -----
Synthetic oil ------
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How Hot is TOO hot for oil temps
- Thread starter Twisted Steel Performance
- Start date
Cumminsfever
Been there, broke that.
General rule of thumb- oil should be within 20* of coolant temp.
schiker
Well-Known Member
For Conventional oil std lube intervals: Kubota, Yanmar, and Deutz say max sustained oil temperature is 248F measured as avg oil temp in pan intermediate to 256F if I remember it correctly. I tried to search some older threads and did n't see them right off.
I don't think there is a catasprophic oil temp except when it looses pressure. It reacts pretty slow to top out. The hotter it gets the shorter its lifespan.
Synthetic I don't know.
I don't think there is a catasprophic oil temp except when it looses pressure. It reacts pretty slow to top out. The hotter it gets the shorter its lifespan.
Synthetic I don't know.
schiker
Well-Known Member
Meant intermittent 256F. Intermittent was not defined/specified.
Not with a 6.5TD loaded. I've seen 275° easy on mine loaded. The 6.5 is a good candidate for synthetic oil.
Greg
schiker
Well-Known Member
schiker
Well-Known Member
I like the idea of synthetic oil for the 6.5.
But I wonder if the max oil temp shouldn't stay about the same even though the oil can take the extra temp.
Thinking along the lines of the common belief that ~ 215-220F is max sustained ECT acceptable coupled with my thought that at avg 220F there exsists a possibility that one or more cylinders are really hot and timing may vary and cause harmonics on the lower end and crank.
I think you can infer from all the parameters the temp of the piston and combustion chamber and a super heated uneven combustion chamber temps is one of the problems on the 6.5 IDI when working hard and it may cause the funky harmonics that tend to kill the 6.5 early. I have said it before I don't think the block metal is passing some metallurgical softening temp at 220F ECT but something else and I propose its the combusition timing and peak cylinder pressures at near TDC. Why it doesn't code for cylinder imbalance is its usually while towing and the engine can't rotate and accelerate uneven enough to trigger imbalance??? And it then becomes a fatique related failure with varing load and frequency/harmonic variables.
Still thinking on why it doesn't code more imbalance injector though but think its a harmonic and hammering at near TDC more than actual piston acceleration differences. Its not a difference in fuel rate just how it combusts I think saying it slightly differently.
But I wonder if the max oil temp shouldn't stay about the same even though the oil can take the extra temp.
Thinking along the lines of the common belief that ~ 215-220F is max sustained ECT acceptable coupled with my thought that at avg 220F there exsists a possibility that one or more cylinders are really hot and timing may vary and cause harmonics on the lower end and crank.
I think you can infer from all the parameters the temp of the piston and combustion chamber and a super heated uneven combustion chamber temps is one of the problems on the 6.5 IDI when working hard and it may cause the funky harmonics that tend to kill the 6.5 early. I have said it before I don't think the block metal is passing some metallurgical softening temp at 220F ECT but something else and I propose its the combusition timing and peak cylinder pressures at near TDC. Why it doesn't code for cylinder imbalance is its usually while towing and the engine can't rotate and accelerate uneven enough to trigger imbalance??? And it then becomes a fatique related failure with varing load and frequency/harmonic variables.
Still thinking on why it doesn't code more imbalance injector though but think its a harmonic and hammering at near TDC more than actual piston acceleration differences. Its not a difference in fuel rate just how it combusts I think saying it slightly differently.
Everyone forgets the oil cooler hoses are the weak link. The GM hoses are not rated real high and tend to get hard and leak and/or fail. So high oil temps can fail hoses over time.
Boiling off 1 quart of oil every 500 miles is in the ballpark. No, not leaking it, not burning it with bad rings: evaporating it off.
Too hot is the moment you scuff a piston. Synthetic or the marketing excuse to label what we do as Synthetic still holds up better at high temps than conventional. Sadly synthetic likes to leak more and will usually leak the oil cooler hoses. I have has bad luck with synthetic and the 1993 oil cooler hoses on my 4.3 gasser even with new GM hoses. Same with the 6.5 and synthetic.
I have run conventional hard and only have had two oil failures. One piston scuffed and the other the high heat and some fuel dilution thinned the conventional out too much and tripped a low oil pressure alarm. Not sure synthetic would have helped the piston scuff issue. Because as temperatures get out of control your oil can still be good, but, the moment you run out of clearance oil can't help you and damage happens.
Load varies the oil temps. The rule of thumb of 20 degrees hotter does not always apply. The cooling system is separate from the oil.
The oil will oxidize at a higher rate and have it's useful life cut in half or more at higher temps. I don't remember the details but Mobile 1 synthetic reps told me this reduced life when I was getting near 300 degrees in a hot rod that specified Mobile 1. It needed an oil cooler and the engines were known to spit rods from rod bearing lube failures. So a higher weight of oil and 1 quart overfilled was a common thing to do. I actually helped with the design/testing of a thicker aftermarket radiator to help the issue.
As I recall 300 degrees is the failure temp of conventional oil. The result is oil sludge and blocking the oil pump pickup screen and general engine failure in short order. Modern gas engines suffer from this. Toyota, Dodge...
Boiling off 1 quart of oil every 500 miles is in the ballpark. No, not leaking it, not burning it with bad rings: evaporating it off.
Too hot is the moment you scuff a piston. Synthetic or the marketing excuse to label what we do as Synthetic still holds up better at high temps than conventional. Sadly synthetic likes to leak more and will usually leak the oil cooler hoses. I have has bad luck with synthetic and the 1993 oil cooler hoses on my 4.3 gasser even with new GM hoses. Same with the 6.5 and synthetic.
I have run conventional hard and only have had two oil failures. One piston scuffed and the other the high heat and some fuel dilution thinned the conventional out too much and tripped a low oil pressure alarm. Not sure synthetic would have helped the piston scuff issue. Because as temperatures get out of control your oil can still be good, but, the moment you run out of clearance oil can't help you and damage happens.
Load varies the oil temps. The rule of thumb of 20 degrees hotter does not always apply. The cooling system is separate from the oil.
The oil will oxidize at a higher rate and have it's useful life cut in half or more at higher temps. I don't remember the details but Mobile 1 synthetic reps told me this reduced life when I was getting near 300 degrees in a hot rod that specified Mobile 1. It needed an oil cooler and the engines were known to spit rods from rod bearing lube failures. So a higher weight of oil and 1 quart overfilled was a common thing to do. I actually helped with the design/testing of a thicker aftermarket radiator to help the issue.
As I recall 300 degrees is the failure temp of conventional oil. The result is oil sludge and blocking the oil pump pickup screen and general engine failure in short order. Modern gas engines suffer from this. Toyota, Dodge...
schiker
Well-Known Member
I agree good points.
Just to say some a little differently. At 266F plus avg oil pan temp convetional oil is breaking down IMO. Can you push fresh oil above 266F yes. If you have already driven many miles and are near a change interval pushing 266F plus oil temp is much harder on the engine as the oil might not be lubing effectively as the viscosity modifiers and additive pkg are worn out hence watch oil pressure doesn't start to dip too low.
And as a side note knowing the temp indicators exit is only part of the story. To really push the envelope you have to know total heat rejection by knowing the cold side too.
Look at marine engines with regular water non pressurized system its a whole nuther ball game for max ECT.
It really can tangent in many directions when trying to give a hard limit for any temperature parameter.
Just to say some a little differently. At 266F plus avg oil pan temp convetional oil is breaking down IMO. Can you push fresh oil above 266F yes. If you have already driven many miles and are near a change interval pushing 266F plus oil temp is much harder on the engine as the oil might not be lubing effectively as the viscosity modifiers and additive pkg are worn out hence watch oil pressure doesn't start to dip too low.
And as a side note knowing the temp indicators exit is only part of the story. To really push the envelope you have to know total heat rejection by knowing the cold side too.
Look at marine engines with regular water non pressurized system its a whole nuther ball game for max ECT.
It really can tangent in many directions when trying to give a hard limit for any temperature parameter.
JayTheCPA
Well-Known Member
Back to the original question as it applies to synthetic, am at best the novice / amateur level but do read the Amsoil literature and am running synthetic in the Burb. Not recalling an upper limit for temp on the synthetic lubes and confident there is one; when in doubt, am sure each vendor will supply tested limits. Do know that towing / severe duty will shorten the life with definite recommendations of analysis if there is either concern or desire to extend drain intervals.
In reading through the question, if it is for a current project in the works, how about a suspenders and belt approach by adding a 2nd oil cooler in place of the empty tranny cooler slot? Seems the best solution is for a pusher fan either in front of the oil cooler and / or empty slot to boost air flow when pulling hard and slow (still trying to figure out a drop-in to work in front of my coolers without modding the grill). As an added minor bump to cooling, a remote & bypass filter (depending on placement) which also adds a little more capacity (PM me if you want a parts list for this).
In reading through the question, if it is for a current project in the works, how about a suspenders and belt approach by adding a 2nd oil cooler in place of the empty tranny cooler slot? Seems the best solution is for a pusher fan either in front of the oil cooler and / or empty slot to boost air flow when pulling hard and slow (still trying to figure out a drop-in to work in front of my coolers without modding the grill). As an added minor bump to cooling, a remote & bypass filter (depending on placement) which also adds a little more capacity (PM me if you want a parts list for this).
Well, this thread has turned out to be a purrty good one so far. I am building a motor now as some of you know, I just haven't started a thread yet, but will soon. A little info as to why I asked the question in the first place....
The motor in question --- 2005 GEP, +20 over Kennedy 18:1 pistons, Hard Blok in the bottom of block to bottom of water hole, studs, pistons coated top,sides,under side, piston squirters, HVHP oil pump, ported & ceramic coated heads runners also coated.... this is the short list for now.... There is lots & lots of ceramic coating in this motor, I will get in to that when I start my build thread, this will be a turbo motor and I will be pulling with it so things are going to get hot...
I have 2 stock type oil coolers I plan to use and have braided lines made up. I think the oil will be able to be cooled good, just was wondering what folks were seeing for oil temps....
Thanks for the input....
And Jay, send me the info you have for the bypass filter, I have been thinking about that.......
The motor in question --- 2005 GEP, +20 over Kennedy 18:1 pistons, Hard Blok in the bottom of block to bottom of water hole, studs, pistons coated top,sides,under side, piston squirters, HVHP oil pump, ported & ceramic coated heads runners also coated.... this is the short list for now.... There is lots & lots of ceramic coating in this motor, I will get in to that when I start my build thread, this will be a turbo motor and I will be pulling with it so things are going to get hot...
I have 2 stock type oil coolers I plan to use and have braided lines made up. I think the oil will be able to be cooled good, just was wondering what folks were seeing for oil temps....
Thanks for the input....
And Jay, send me the info you have for the bypass filter, I have been thinking about that.......
Are you ceramic coating the precups? This would be a high heat loss area you would want to slow down IMO.
I suggest one of the oil cooler kits our vendors sell with different oil cooler hoses than the factory stuff.
I suggest one of the oil cooler kits our vendors sell with different oil cooler hoses than the factory stuff.
Yes I am coating the cup area and using a Thermal Barrier ( heat stop ) in all the runners that will also slow down the heat soak to the head. I will have more pics posted in my album " My 6.5 towing build " next week of the heads, there are lots of pics of the build there now, just not done with the heads yet..
I have found a large 30 row cooler on flebay I might use, I have 2 stock coolers now on the shop wall, I would just have hoses made up for what ever ones I use.