Oil Temperature?

[ACHiPo]

I have a 470ci BBM FE in a Cobra replica.  I have Smith's gauges, and the oil temp doesn't come up to temp the way I think it should.  The car has an oil cooler, but even with it taped off, the oil temp reads around 40C after 20 min or so.  I've seen it as high as 60C, but I'd expect the oil temp to be at least as high as the water at steady state (the water gets to 80 and stays between 80 and 90C during operation).  The oil temp gauge is mechanical.  I'm wondering if it is a calibration issue, or if the oil is really only getting up to 40C?

What suggestions do you all have?

[67428GT500]

Are you Canadian? U.S. gauges don't read in centigrade. My Shelby holds seven quarts of oil. Even when it's 100 degrees here it stays at about 175 ( 80C)  degrees. When it's about 50 degrees out I run more about 120 degrees. ( 50C)

                                                                   -Keith

[blykins]

I'd bypass the oil cooler altogether.  I haven't seen a Cobra yet that really needs one.   I've got engines in Cobras in California and Texas and they're not needed, even there. 

Keith, Cobras were based on cars made in the UK.....Smiths gauges are in Celsius.

[67428GT500]

I know about Smith Gauges. Most U.S. versions are in PSI and Fahrenheit. I'm well aware of where Cobras were made.  ( Real ones)

[Gaugster]

Any oil temperature below the boiling point of water is a concern. However the temperature at the sensing  unit can be 30 or 40F less than deeper in the block. A  second measurement device even temporary can help with calibration .

[ACHiPo]

Any oil temperature below the boiling point of water is a concern. However the temperature at the sensing  unit can be 30 or 40F less than deeper in the block. A  second measurement device even temporary can help with calibration .

Gaugster,
Thanks.  That's kinda what I suspect--the measurement bulb is not in the right place or the bourdon tube is out of cal.

'67,
My Smiths temp gauges came marked in centigrade and pressure is in psi and speedo is mph. I admit while I did unnatural things to get the correct fuel gauge in my replica, I did not pay any attention to the units on the gauges.

[ACHiPo]

I'd bypass the oil cooler altogether.  I haven't seen a Cobra yet that really needs one.   I've got engines in Cobras in California and Texas and they're not needed, even there. 

Keith, Cobras were based on cars made in the UK.....Smiths gauges are in Celsius.

Brent,
Disconnecting the oil cooler is a possibility.  I suspect, however, that most of my issue is calibration/correlation between the oil temp and water temp since I don't see any difference in oil temp with the oil cooler masked off.

Thanks,
Evan

[C6AE]

Any oil temperature below the boiling point of water is a concern. However the temperature at the sensing  unit can be 30 or 40F less than deeper in the block. A  second measurement device even temporary can help with calibration .

Why so hot?

[Joe-JDC]

There is horsepower in hot oil.  Joe-JDC

[cjshaker]

Not to mention evaporating off condensation in the engine and any water that makes it's way in to the pan (under the right circumstances, condensation can get thick enough to run droplets of water down into the pan).

[ACHiPo]

Not to mention evaporating off condensation in the engine and any water that makes it's way in to the pan (under the right circumstances, condensation can get thick enough to run droplets of water down into the pan).

That's my primary concern--I want to drive off the water.  I suspect I am as my oil looks and feels good, but the fact that the temp is reading relatively cold makes me wonder.

Evan

[Gaugster]

The pressure gauge can give you some indication of when the oil is nice and hot. Not a number though. With the exception of the high volume or high pressure pumps it is usually easy to note the idle oil pressure will reduce as the engine comes up to temperature.

+1 to Joe-JDC and Cjshaker. They were on point as usual.

[Drew Pojedinec]

Non contact thermometer IR gun’s are great for this. Quick verification of gauge function.

[ACHiPo]

The pressure gauge can give you some indication of when the oil is nice and hot. Not a number though. With the exception of the high volume or high pressure pumps it is usually easy to note the idle oil pressure will reduce as the engine comes up to temperature.

+1 to Joe-JDC and Cjshaker. They were on point as usual.

My oil pressure gauge acts normal once the temp gets up to 40C, which is one reason I suspect my oil temperature gauge is inaccurate.  The oil pressure when cold is ~70 psi and doesn't change much with RPM (I am running 15W40 and keep the revs below 3k until the water temp gets up to 80C).  Once the oil temp gauge moves off the peg, the oil pressure rises and falls with RPM as expected, dropping down to ~28 psi at idle when the oil temp gets to 40C.

[ACHiPo]

Non contact thermometer IR gun’s are great for this. Quick verification of gauge function.

That's a good idea.  I was also thinking of sticking a thermocouple down the dipstick tube once the engine was hot and after I turn it off.

[67428GT500]

Non contact thermometer IR gun’s are great for this. Quick verification of gauge function.

That's a good idea.  I was also thinking of sticking a thermocouple down the dipstick tube once the engine was hot and after I turn it off.

I was about to mention just that. It would allow you to measure the temperature in the sump.
                                                                    -Keith

[Gaugster]

The IR guns are very handy for something like this. Just be sure to use the proper (emissivity) material setting. Pointing it at surfaces with different materials like case iron vs aluminium will give a different reading even if the actual temperature is the same.

[Drew Pojedinec]

Indeed gaugster.
Shooting a raw black iron pipe will not be as accurate as a painted pipe.
Anyway, there are 65 gauges in my engine room, ir and a master gauge are only way to keep after them all.

[C6AE]

I do agree with Joe there is horsepower in hot (thin) oil, but have a problem with having to "boil" the water.
You don't have to boil water to evaporate it, a pan sitting out in the sun will do that.

[Gaugster]

I do agree with Joe there is horsepower in hot (thin) oil, but have a problem with having to "boil" the water.
You don't have to boil water to evaporate it, a pan sitting out in the sun will do that.

A fair comment and nothing that I wish to debate. I like it hot! The 'health' of an engine's oil depends on many factors. The type, usage, air/water cooled, change frequency to name a few. To your example,  that same pan will have dew (frost in my case) the next morning. More heat will increase the rate of evaporation.

[cjshaker]

I do agree with Joe there is horsepower in hot (thin) oil, but have a problem with having to "boil" the water.
You don't have to boil water to evaporate it, a pan sitting out in the sun will do that.

Not sure how you can compare a pan of water sitting in the sun to the internals of an engine. An engine is pretty much sealed, except for maybe a breather or two. Moisture can easily accumulate from temperature and dew point changes, and it does not readily evaporate inside that environment. I've seen oil pans rust...from the inside out, cylinders rust from condensation etc etc. And oil will float on water, so any moisture that gets in the pan will be trapped until it's circulated and heated enough to evaporate. Engines that run too cold will also produce sludge, so heat is essential to a degree (no pun intended) to keep the inside clean.

[John67427]

 A friend of mine had an ERA Cobra that had an FE in it. I remember him calling me that he thought the oil temp gauge was bad as it to so much longer to get heat into the oil than the water temp. The oil definitely takes longer get to a temperature than the cooling system. Just an observation not scientific.

[Drew Pojedinec]

Chlorinated paraffins contact moisture and makes hydrochloric acid. That is more responsible for rusting inside an oil pan.

Is something we monitor on the large marine diesels as it is common to go 20,000 hours on lube oil before changing.

[machoneman]

Bro' James had a near new 1970 Boss 302 with the Drag Pack (think that was the name) options inculding the rare oil cooler. After driving the car for awhile, we figured that even in mainly warm-hot weather city driving, the oil never really got very warm let alone hot.

Although the oil was clear and not frothy from moisture, we made up a simple cover to totally block the cooler. Problem solved and proved to us the cooler should have been a track-only thing.

[cjshaker]

Chlorinated paraffins contact moisture and makes hydrochloric acid. That is more responsible for rusting inside an oil pan.

Is something we monitor on the large marine diesels as it is common to go 20,000 hours on lube oil before changing.

Drew, I'm not sure what your point is here? I don't know anything about chlorinated paraffins, but since moisture is still required to produce the acid, isn't that basically making the same point that I made? That moisture is bad? The engines that I saw with those oil pan problems were all engines that were short tripped, where the oil was not allowed to heat up enough to burn off the moisture in the engine. They get 'sludgy' and the moisture gets trapped in the bottom of the pan and causes them to rust out. Acid or not, they would not rust if it were not for the trapped moisture.

I'm curious what oil temps you typically see, or like to see, in your tug diesel engines?

[C6AE]

Chlorinated paraffins contact moisture and makes hydrochloric acid. That is more responsible for rusting inside an oil pan.

Is something we monitor on the large marine diesels as it is common to go 20,000 hours on lube oil before changing.

This is a good point, which is why lube oils by design have water emulsifiers added to keep moisture in suspension. As oil is moved through the engine, the heat generated by combustion in addition localized heat from working bearings is sufficient to evaporate any accumulated condensation. Typically this water is removed by PCV. Most engine lube oil systems are designed to run at the same temperature as the coolant.

[67428GT500]

With few exceptions, oils are designed to operate at a maximum of 230-260 degrees. Oil boils at about 500 degrees.  Hot Rod did an article a few years ago on just this question.
This may be somewhat helpful.

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

[Drew Pojedinec]

Doug, my point was simply to reconfirm the importance of ridding water from an engine. Run it hot, change oil often. Run a good pcv. Also pays to be choosy regarding the oil you use. Some are more prone to creating acid than others due to the base oils.

In the case of marine engines, 225 for four strokes, 200 for two strokes.
My 10,320ci two strokes cruise at 166 water temp, 190 oil temp, 550egt.
Generally tho two strokes need to be on the cooler side than normal due to seeing combustion every time the piston goes down. So more localized heat, greater oil and water flow to carry it.
The mains here currently have 35,000 hours since last overhaul. Last time I checked bearings and retorqued was when I changed the oil, 10,000 hours ago.
Fun fact about the oil I run here, no zddp. Even 10ppm is enough that we’d have to change it. Any more and the silver coated bearings overheat and make crankcase explosions (trust me, they suck)

[ACHiPo]

Bro' James had a near new 1970 Boss 302 with the Drag Pack (think that was the name) options inculding the rare oil cooler. After driving the car for awhile, we figured that even in mainly warm-hot weather city driving, the oil never really got very warm let alone hot.

Although the oil was clear and not frothy from moisture, we made up a simple cover to totally block the cooler. Problem solved and proved to us the cooler should have been a track-only thing.

I fab'd a cover out of ceramic wool/aluminum heat shield material.  Will test it out this weekend, and confirm oil temp with a TC.

A friend of mine had an ERA Cobra that had an FE in it. I remember him calling me that he thought the oil temp gauge was bad as it to so much longer to get heat into the oil than the water temp. The oil definitely takes longer get to a temperature than the cooling system. Just an observation not scientific.

My oil definitely takes about 10 min longer to move off the peg than the water.  Once it comes up to 40C-60C, however, the pressure gauge makes me think it's at temp.

[cjshaker]

Doug, my point was simply to reconfirm the importance of ridding water from an engine. Run it hot, change oil often. Run a good pcv. Also pays to be choosy regarding the oil you use. Some are more prone to creating acid than others due to the base oils.

In the case of marine engines, 225 for four strokes, 200 for two strokes.
My 10,320ci two strokes cruise at 166 water temp, 190 oil temp, 550egt.
Generally tho two strokes need to be on the cooler side than normal due to seeing combustion every time the piston goes down. So more localized heat, greater oil and water flow to carry it.
The mains here currently have 35,000 hours since last overhaul. Last time I checked bearings and retorqued was when I changed the oil, 10,000 hours ago.
Fun fact about the oil I run here, no zddp. Even 10ppm is enough that we’d have to change it. Any more and the silver coated bearings overheat and make crankcase explosions (trust me, they suck)

I find it amazing that you go that long between oil changes, especially with diesels. All of my campus grounds vehicles have gone to Kubota diesels, and it only takes a few hours run time for the oil to turn black from impurities. I realize it's a big jump from my little diesels to your monster, but diesels are dirty engines all the way around, from what I've experienced. I can't even wrap my head around a 20,000 hour oil change schedule, but your engines seem to go against conventional car engine wisdom, at every level.

[Drew Pojedinec]

We actually don’t have a change interval, I do it every 20 just cuz I feel like it.
2 engines at 350gal each.
Being two strokes they consume 5 gal a day each while at power and monthly samples sent to the lab. So, different scenario.

[machoneman]

Sounds like my old grocery getter I-6 '63 3-on-the-tree 2-dr. Chevy BelAir!

Got it cheap ($200) in fine shape except it was a big oil burner. Took 1 quart every 200 miles or so with one badly chopped up ring set on #5 (how that happened, who knows!). Back then, circa 1969, I'd go to Sears Roebuck's Oak Brook, IL service center where they sold recycled oil for $1.00 (yes one dollar!) for a gallon of 10W-40.

Point is, like Heo's diesel's, I never had to change the oil as in 1,000 miles, the entire pan capacity, 5, quarts, got 'changed' on the fly, so to speak! 

[runthatjunk]

Doug, my point was simply to reconfirm the importance of ridding water from an engine. Run it hot, change oil often. Run a good pcv. Also pays to be choosy regarding the oil you use. Some are more prone to creating acid than others due to the base oils.

In the case of marine engines, 225 for four strokes, 200 for two strokes.
My 10,320ci two strokes cruise at 166 water temp, 190 oil temp, 550egt.
Generally tho two strokes need to be on the cooler side than normal due to seeing combustion every time the piston goes down. So more localized heat, greater oil and water flow to carry it.
The mains here currently have 35,000 hours since last overhaul. Last time I checked bearings and retorqued was when I changed the oil, 10,000 hours ago.
Fun fact about the oil I run here, no zddp. Even 10ppm is enough that we’d have to change it. Any more and the silver coated bearings overheat and make crankcase explosions (trust me, they suck)

I find it amazing that you go that long between oil changes, especially with diesels. All of my campus grounds vehicles have gone to Kubota diesels, and it only takes a few hours run time for the oil to turn black from impurities. I realize it's a big jump from my little diesels to your monster, but diesels are dirty engines all the way around, from what I've experienced. I can't even wrap my head around a 20,000 hour oil change schedule, but your engines seem to go against conventional car engine wisdom, at every level.

I don't know if you have any experience with newer diesel pickups by my new to me 04 superduty stays suprisingly clean with 170K on the odometer.  Now my 74 Mercedes 240D with a ton of blowby, I can almost see the oil change to black as I'm pouring it in, that oil is nasty.!!

[e philpott]

Blowby oil burner 2002 Chevy Cobalt 2.2 will turn new oil black in 30 seconds or less of run time  , the amount of time it takes to start engine after  a oil change and let the oil circulate through a new filter then shut off to check level and oil will be black as night ….. set of new piston rings from the local GM dealer later and oil will now stay clean on a 3000 mile oil change service interval

[ACHiPo]

Took the car out for about an hour today after wrapping the oil cooler in metallized 3/8" ceramic wool thermal barrier.  The air temp was in the low 60s.  The water gauge read between 80C and 85C.  The oil temp read a tad above 40C.  I put an instant read thermocouple on the remote oil filter mount and it read 180F (82C).  That makes me feel better that everything (except the oil temp gauge) is working the way it should.  I'm guessing either it's just a calibration issue with the bourdon tube, or the tube is cooling the liquid inside and messing up the reading.  I can live with it being low, as long as the oil is not too cold.

[machoneman]

Great! Bet even in 90F weather, the oil temps will equalize to your water temps on longer drives.

[fryedaddy]

what about oil level vs horse power.i saw a video where they gained a few hp by letting a quart of oil out of the pan.it makes me wonder if i should run 5 vs 6 quarts in my stock oil pan.

[My427stang]

what about oil level vs horse power.i saw a video where they gained a few hp by letting a quart of oil out of the pan.it makes me wonder if i should run 5 vs 6 quarts in my stock oil pan.

I wouldn't, two things working against you with a stock oil pan.  1 is total quantity in operation, 2 is that they aren't very well baffled during a hard acceleration.  It doesn't take much either, my car when it was a pretty mild 427, in traffic, could wiggle a gauge with a decent stoplight launch.

[shady]

My stock 289s always ran better a quart low.