what is optimum oil temperature?

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in the current of machinerylubrication,
http://media.noria.com/ml/
there's an article about natural gas engine lubrication. It states that at oil temps of 175F and below nitration occurs. And at oil temps of 190F and above oxidation starts to happen. This is for a piston engine fueled by natural gas. My question though is, are those nitration/oxidation temps relatively the same for gasoline burning engines? And if so, then would the optimum operating oil temp be around 180-190F? I ask because, on my LS1 with a 160F thermostat and a digital oil temp gauge, I've been seeing temps in the 190-210F range the past two months on 10w-40 dino oil. That made me somewhat happy. It's gotten cooler recently and I noticed the oil temp took a lot longer to reach 190F. I put castrol 0w-30 in last week, and oil temps run the same- 190F range with it taking a while to reach that temp since it's been 50-70F ambient outside temp.
thoughts, comments?

fyi, during July and Aug with 80F+ weather running the 10w-40 (oil analysis coming soon too) and 160F thermo, it would hold at 190-200F range when on the highway, unlike the supertech 10w30 full syn which had run 220F on my 300 mile trip to upstate NY. But with the 10w40, it had no problem running 220F steady at 30mph or below or if I romped on it, and would climb to 250F easily if in stop&go traffic. It did however cool down easily, back to 200F, when cruising on the highway, which the 10w30 never did.
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[ September 29, 2004, 10:58 PM: Message edited by: 1 FMF ]
 
Permacool sells a thermostatic bypass valve for their oil coolers that has a 180°F set point. I think 180-220 is a good range for engine oil. It has not precise temperature control, so don't worry. Unless you spend the money for an air-cooled cooler plus a Permacool or Amot thermostatic valve, you have no control.


Ken
 
So you haven't seen that a thinner (0w-30) runs hotter or cooler than the heavier (10w-40) have you? Interesting that the SuperTech synthetic (group 3) runs so hot.
 
Why are you running with a 160 stat??? I personally think its a bad idea. Although on this engine there may be a logical reason for it.
 
quote:
Originally posted by Al:
Why are you running with a 160 stat??? I personally think its a bad idea. Although on this engine there may be a logical reason for it.
Click to expand...
While it's not entirely necessary, a 160 thermostat is ok to use on the LS1 in the hot summer. For a lot of people they find they get mild detonation, especially if they live in a hot area and can only get 91 or 92 octane. So the 160 thermostat helps keep coolant temps low enough to eliminate most of the detonation.

In my climate I don't feel the need for a colder thermostat in my LS1 Corvette though. The stock one in my car is a 178F unit anyways, and I typically see 189-192F coolant temps. I've got my fans reprogrammed to come on sooner so I never see my coolant go over 198 even when driving hard. This also helps keep my oil temps lower too, I now never go above 210F, most of the time it's closer to 200F. My tranny temps are nice too, not going above 185F most of the time either. If we have a hot summer next year and I see all of these temps go up, I will go with a 160 thermo in mine too.
 
a 160F doesn't mean the coolant is 160F on this motor. It still runs 180-220F depending on driving conditions and how hot outside it is. With winter coming I will either put the stock 195 stat back in or buy a 180.

with the supertech running 220's, that was the first oil I ran using the gauge. I did rewire the gauge under the console after that so there's a slim possibility that the readings were high, but I doubt it. I wouldn't be able to verify it unless I run that oil again, and next summer to be scientific about it. But when I switched from that to the 10w-40 in July-Aug I changed nothing and immediately noticed 190-210F oil temps vs. 210-250F. Don't take this to be the holy grail though, I'm just posting initial observations.

[ September 30, 2004, 01:25 PM: Message edited by: 1 FMF ]
 
quote:
Originally posted by TheTanSedan:
220F.

See "Interesting Articles" Forum, thread on oil versus coolant temperature for a good read.

"Some feel that 88C/190F is the ideal oil sump temp? But others post temps in the 225 - 250F range"
Click to expand...
that was the only mention of actual temperature I saw there. That thread basically concludes oil temp runs a little hotter than coolant temp. What I want to know, uhumm Terry
smile.gif
, is in an ideal world what oil temp should you shoot for and why?
So far my understanding is that temps too cool increases nitration (not exactly sure what that is other than it's not good) of the oil with NOx emissions from combustion, which kills the oil. And too hot oxidizes the oil and kills it. And according to the article from my link above, those numbers are 175F and 190F.

My thinking was getting oil temp close to 212F/100C to burn off moisture. I would think that would help burn off combustion by-products and fuel dilution as well, and I suppose for that the hotter the better as long as it didn't hurt the oil. And when you look at viscosity specs for oil, it is rated at 100C or 210F. So that reasoning, to me, made sense.

However, just because people report oil temps typically running 220-250F I don't think that is because that is best for the oil. I believe the auto makers run engines hotter these days for emissions and fuel economy reasons, not the oil. Or I should say at the expense of the oil. My point of view is from a lubrication standpoint, and for engine longevity, cleanliness, and so on. The automakers are only interested in lower emissions, fuel economy, and meeting 3 years/36000 miles.
 
Well since my thermostat settings are as foolow:
Initial-opening 80-84 C, full-open 95 C

I would suspect that my oil temp will be arround 100C in normal driving and 110-120C during the high speed driving...

oil runs about 10-15 C hotter then coolant right?
 
Assuming the engine timing is correct, if you get a lot of detonation (pinging) try a colder heat range plug or higer octane fuel.
 
quote:
Originally posted by zoomzoom:

oil runs about 10-15 C hotter then coolant right?
Click to expand...
I would have to say that depends. I'm sure things like the type & design of an engine would have the greatest influence, along with run time and operating rpm. So I wouldn't assume that. The only way to know of course would be to hook up a gauge.
I know with my car, within the 1st 15 minutes of cold startup with outside temp having been 55-70F and average rpms between 1k -2k, the coolant temp gauge will read in the 180-200F range but my oil temp can still be as low as 100F. The oil certainly does not warm up as fast as coolant, and it cools off faster than coolant. Unfortunately, I can't tell accurate coolant temp on the dash by the gauge, it differs very little between I'd say 170F and 220F, so I can only estimate my coolant temps. But if I only had a 20 minute drive in the morning, and sometimes I have, my coolant temps would hit around 190F but according to the oil temp gauge it only gets to 160-170F.

[ September 30, 2004, 04:50 PM: Message edited by: 1 FMF ]
 
quote:
Originally posted by Geoff:
Assuming the engine timing is correct, if you get a lot of detonation (pinging) try a colder heat range plug or higer octane fuel.
Click to expand...
The detonation isn't caused by a hot plug, it's caused by a hot cylinder head with coolant temps typically running 220F. So I don't think a colder plug would help, probably hurt if anything by not running hot enough to stay clean when running normal coolant temps. And I'm running 93 octane. The computer on the LS1 will retard timing automatically, which apparently isn't enough to counter the effect of 220+ coolant temps. As for using octane boosters or blending race gas in a daily driver, for their cost I'd rather back off on the throttle. I'm not in that much of a hurry.
 
If the thermostat is already wide open with a stock or a cooler one, what is the advantage of having a cooler one? Open is open.
 
Interesting that the SuperTech synthetic (group 3) runs so hot.

I agree. Why would this be so? Some other factor involved?
 
In time of the dino - more bhp was achieved at 80c but engine run at 90c for heater and oil at 100c. If oil constantly was at 110c an oil cooler would be fitted. With synths the oil should be able to withstand temps of 125c+.

The AW additives also need temp to work so I let the oil get up to temperature before going for high revs, and prefer an oil with esters in package.
 
I see oil pan temps of 170f-180f, I don't know what my coolent temp is, but I do know it will boil if I remove the Rad cap.
Are desirable 'High' oil temps somthing that has developed with modern motor oils? My car like many 'Sports' cars built in the 60's and 70's had the option of being fitted with an oil cooler from the factory, clearly, in my case it would not be needed and in fact would be detemental to the engine if it were.
 
Spitty

Sports cars were ideally used at high revs and generate oil higher temps. In these days I had a choice of Castrol GTX 20/50 or Duckhams, so any temps over 100c the thoughts of an oil cooler with thermostat at 80c was considered more essential. With the advent of synths running higher temps is less of a problem and the weight of oil cooler can be removed.

The K engine used in current MGF sports car has reduced water within engine to speed warm up to operating temp. Oil coolers are still considered especially water /oil to reduce thermal shock.
 
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