Oil temp 100oC road use

[Chimp871]

As title says I've installed an oil temp gauge. The sensor is installled next to oil filter and I'm seeing oil temp around 100oC for town use and 110oC when driving with spirit. You can see location in Pic maybe its not the best place for the sensor?

Oil pressure guage (fwiw) is around 30psi and water temp is solid at 88oC.

Normal?

[QBee]

I believe so. We need Phazed along to pronounce, he has a Spa oil temp gauge in his car.

[bobfather]

My temperature sender is fitted in the same location and I see the same temperatures as you. Some folk have experienced lower temperatures but I suspect that they have located their senders where they experience cold air flow. These brass senders easily cool so it's important to either locate out of drafts or wrap them in insulation

Fully synthetic oil is okay up to 150degC so 110degC appears fine for me

[phazed 11.83]

With my Spa gauge the readings are as follows.

Casual motoring, low 80s
Spirited road driving, low 90s
Trackwork, I usually pull off track at 115

These seem pretty accurate. My temperature pick up is where the original oil sender screws in .

[phazed 11.83]

I should have said, that is using an oil cooler which is approximately 2/5 the size of my radiator .

[N7GTX]

bobfather said:

My temperature sender is fitted in the same location and I see the same temperatures as you. Some folk have experienced lower temperatures but I suspect that they have located their senders where they experience cold air flow. These brass senders easily cool so it's important to either locate out of drafts or wrap them in insulation

Fully synthetic oil is okay up to 150degC so 110degC appears fine for me

From previous posts I believe you have some chemical engineering background? I found this evaluation of semi-synthetic v synthetic oil, in this case Shell, done in in 2015. It is a comprehensive evaluation of the two oils and how they perform after 24 hours all the way through to 240 hours at three temperatures namely, 120c, 149c and 200c.
A lot of the content is way over my head but, correct me if I am wrong, it does seem that the viscosity of semi is as virtually as good as synthetic especially at the lower temperature of 120c. In fact, if I understand the analysis correctly, semi synthetic at 120c is in some parts slightly better due to the rapid decline in viscosity over the first 24 hours of synthetic oil at 120c. At temperature ranges over this then synthetic is more stable and in layman's terms lasts longer.
So, my question is this. If our engines are kept below 120c then there is no advantage in using synthetic oil. Or is there? The reason I ask is that after my engine was fully rebuilt I was told to only use 10/40 or 15/40 semi synthetic oil, never synthetic. In fact, I have read the terms of the warranty and it states categorically that the use of synthetic oil will invalidate the 3 year warranty.

Any thoughts on this?

The article is here: http://www.mdpi.com/2075-4442/3/1/54/pdf

Edited to correct!

Edited by N7GTX on Monday 17th July 11:26

[QBee]

N7GTX said:

The article is here: file:///C:/Users/Iain/Downloads/lubricants-03-00054%20(2).pdf

I'd like to read this,as i use Shell 10w60 synthetic at present.
But that link is to your C drive on your computer, Iain

[bobfather]

phazed 11.83 said:

With my Spa gauge the readings are as follows.

Casual motoring, low 80s
Spirited road driving, low 90s
Trackwork, I usually pull off track at 115

These seem pretty accurate. My temperature pick up is where the original oil sender screws in .

Just a thought, Accepting that some folk have seen low temperatures when locating the sender in an air flow even without an oil cooler. I'm wondering if wrapping some exhaust wrap around the exposed brass part of the sender would result in marginally higher gauge readings. I'd do this experiment myself but for the fact that my sender is located in a sheltered location

[bobfather]

QBee said:

I'd like to read this,as i use Shell 10w60 synthetic at present.
But that link is to your C drive on your computer, Iain

Thank you I just tried the same thing so that I could answer the question

[Chimp871]

bobfather said:

My temperature sender is fitted in the same location and I see the same temperatures as you. Some folk have experienced lower temperatures but I suspect that they have located their senders where they experience cold air flow. These brass senders easily cool so it's important to either locate out of drafts or wrap them in insulation

Fully synthetic oil is okay up to 150degC so 110degC appears fine for me

I read elsewhere on here that the oil typically runs 10-15 degrees higher than coolant temp.

I'll take it as gospel then but am thinking about a mocal/modine oil cooler (using coolant) like this

http://www.ebay.co.uk/itm/152525848970 or http://www.ebay.co.uk/itm/222567458224

[N7GTX]

bobfather said:

QBee said:

I'd like to read this,as i use Shell 10w60 synthetic at present.
But that link is to your C drive on your computer, Iain

Thank you I just tried the same thing so that I could answer the question

Doh, too early for me. Sorry.

Try this for the pdf download: http://www.mdpi.com/2075-4442/3/1/54/pdf

[bobfather]

Chimp871 said:

I read elsewhere on here that the oil typically runs 10-15 degrees higher than coolant temp.

I'll take it as gospel then but am thinking about a mocal/modine oil cooler (using coolant) like this

http://www.ebay.co.uk/itm/152525848970 or http://www.ebay.co.uk/itm/222567458224

My logic says provided the sender/gauge are matched and reasonably accurate then it is not possible to get a false high reading because there is nothing there that could transfer more heat onto the sender. It is possible however that the brass sender could lose heat by radiating it to the surrounding air. Therefore if two cars with the same engine configuration but with senders in different locations that recorded different readings then then a low reading is more likely to be false than a high reading. This system can read low by losing heat but it can't easily read high by gaining heat. There's nothing that could add that extra heat

[bobfather]

N7GTX said:

From previous posts I believe you have some chemical engineering background? I found this evaluation of semi-synthetic v synthetic oil, in this case Shell, done in in 2015. It is a comprehensive evaluation of the two oils and how they perform after 24 hours all the way through to 240 hours at three temperatures namely, 120c, 149c and 200c.
A lot of the content is way over my head but, correct me if I am wrong, it does seem that the viscosity of semi is as virtually as good as synthetic especially at the lower temperature of 120c. In fact, if I understand the analysis correctly, semi synthetic at 120c is in some parts slightly better due to the rapid decline in viscosity over the first 24 hours of synthetic oil at 120c. At temperature ranges over this then synthetic is more stable and in layman's terms lasts longer.
So, my question is this. If our engines are kept below 120c then there is no advantage in using synthetic oil. Or is there? The reason I ask is that after my engine was fully rebuilt I was told to only use 10/40 or 15/40 semi synthetic oil, never synthetic. In fact, I have read the terms of the warranty and it states categorically that the use of synthetic oil will invalidate the 3 year warranty.

Any thoughts on this?

The article is here: http://www.mdpi.com/2075-4442/3/1/54/pdf

Edited to correct!

Edited by N7GTX on Monday 17th July 11:26

I have no real knowledge about the true similarity of fully and semi synth oils. I also believe the 'good up to 150degC' thing is questionable because oils have different working heat ranges as per their grade numbers. As a safety margin I was looking for fully synth oil not to exceed 120degC. It is also worth noting that the oil will see temperatures in excess of those reported at the sender. The heat is generated in proximity to the cylinders and by agitation mostly in the bearings and then dissipated into the body of oil. I would therefore say that continuous operation with a gauge reading of 120degC would prematurely age the oil. Normal cruising gives me a gauge reading of 100degC, I believe that this is okay for a 6k miles change period and that my oil looks brand new when I drop it out. You know if your oil has overheated, it will smell sulphurous and be very dark on the dipstick

[ChimpOnGas]

A fully synthetic should be avoided for the first 10,000 miles following a rebuild, after that and assuming you choose a synthetic of the correct grade with at least 1000ppm zinc dithiophosphate (ZDP) there is absolutely no reason why a synthetic should not be used.

The temperature range of a synthetic and it's tolerance of higher temperatures are clear benefits but as the oil in a street driven RV8 is unlikely to exceed 110c (even one without an oil cooler) this is of little consequence. However, the one area we can all benefit from when switching to a synthetic is it's working life and so the extended change frequency, this is mostly a cost advantage but there are carbon saturation benefits too.

All oils break down and it doesn't matter if its synthetic or mineral, over time the chain of molecules that ultimately delivers the lubricity becomes fractured, the two key influencing factors to this process are heat and the shear stresses placed on the oil. Synthetics are more tolerant of both heat & shear so it takes longer for the chain of molecules to breakdown, as we are not really pushing the heat limit of a good mineral oil in the RV8 in our case the only real benefit of switching to synthetic is the extended change intervals.

You now need to look at that cost benefit and do your sums, a quality synthetic will typically be 45% more expensive and often much greater than that when compared with a similar quality mineral that carries the same additive package and that essential minimum 1000ppm zinc dithiophosphate. So if switching to a synthetic only extends your oil change interval by 45% more miles or less the truth is you may as well just use that quality mineral because it'll be cheaper and deliver the same performance as the 45% more expensive synthetic.

The regularity of oil changes is a very critical point to consider, in an RV8 running petrol I'd favor a more frequent change schedule using a good quality mineral over extended change periods using synthetic... and the lower price of that quality mineral will allow this. For example if you went with a conservative 3,000 mile oil change using Classic Oils excellent own brand Heritage 20w/50 which is £17.00 for 5 litres you'd need to keep the £52.00 per 5lt Millers CFS 15W60 in the engine for at least 9,000 miles just to achieve the same cost per mile.

Now consider the carbon saturation of the oil at 9,000 miles and you start to see why you're better off just using a good quality mineral oil and changing it out more frequently, carbon itself isn't damaging until it starts to lay down on engine internals causing restrictions in oil galleries and can also limit the correct function of our hydraulic tappets. This is why it's so important to keep the carbon suspended in the oil and synthetics really aren't any better at doing this than a good mineral with a proper detergent package, for this reason and the temperature point I made earlier the RV8 running a good mineral changed between 4-5,000 miles will be a healthier engine than one running a synthetic for double the miles. And don't think you'll be giving you engine better protection if you spend more on the synthetic and adopt the same 4-5,000 mile change interval as the mineral, because it won't, you'll just be wasting money

While we'd all like to think paying more for a synthetic oil will make our engines last longer it really isn't the case, while cost isn't a sexy angle when discussing engine oils on a car enthusiast's forum, when you really understand the true elements that effect oil choice getting the best quality (highest API rating) and the correct additive package for the best value is what we should be looking at, for all the above reasons the synthetic vs mineral debate becomes very much secondary.

Finally you may assume after all that I use a mineral but that's actually not the case, I have done the cost per mile vs quality calculations and settled on a 5,000 mile 7 litre change using 5l of Penrite fully synthetic HPR15w/60 at £33 and topping off the last two litres with Classic Oils mineral own brand Heritage 20w/50. The remaining 3 litres of Heritage 20w/50 gets consumed by the engine over the 5,000 miles so each 5k mile change period costs £33 + £17 = £50. I run a synthetic media Royal Purple 20-253 oil filter which are excellent but admittedly are expensive, synthetic media filters are superior by design having been developed to offer extended 20,000 mile change intervals on hard working diesel commercial vehicles that dirty their oil much faster than any petrol engine car would. Running clean burning LPG I never come close to pushing the capabilities of the 20-253 RP filter so it gets renewed every second oil change IE every 10,000 miles, this makes it little or no more expensive than using a significantly inferior traditional cellulose filter.

In summary, when choosing an engine oil there really is no benefit in running something that's over specified for the application, assuming you choose the right grade of quality oil that has the correct additive package for our RV8 flat tappet engine the frequency you change that oil and the use of a quality of filter becomes the far more important deciding factor.

Price, Performance & Quality = Best Value Engine Protection

[phazed 11.83]

bobfather said:

My logic says provided the sender/gauge are matched and reasonably accurate then it is not possible to get a false high reading because there is nothing there that could transfer more heat onto the sender. It is possible however that the brass sender could lose heat by radiating it to the surrounding air. Therefore if two cars with the same engine configuration but with senders in different locations that recorded different readings then then a low reading is more likely to be false than a high reading. This system can read low by losing heat but it can't easily read high by gaining heat. There's nothing that could add that extra heat

Just to give an alternative opinion, (through heavy track use!).

I agree, cruising gives a very similar like for like, (although usually about 90 degrees at legal+10) but hard use on my engine, (bigger=more heat) and we are talking hard track use for 20 minuets+ will give a steady water temp of about 85 degrees and the oil temp rising gradually to 115-120 degrees.

I normally come off track at 115 degrees which equates to about 20 minutes. On a hot day that will be sooner and on a cool day I could run for longer.

[GR_TVR]

ChimpOnGas said:

A fully synthetic should be avoided for the first 10,000 miles following a rebuild, after that and assuming you choose a synthetic of the correct grade with at least 1000ppm zinc dithiophosphate (ZDP) there is absolutely no reason why a synthetic should not be used.

The temperature range of a synthetic and it's tolerance of higher temperatures are clear benefits but as the oil in a street driven RV8 is unlikely to exceed 110c (even one without an oil cooler) this is of little consequence. However, the one area we can all benefit from when switching to a synthetic is it's working life and so the extended change frequency, this is mostly a cost advantage but there are carbon saturation benefits too.

All oils break down and it doesn't matter if its synthetic or mineral, over time the chain of molecules that ultimately delivers the lubricity becomes fractured, the two key influencing factors to this process are heat and the shear stresses placed on the oil. Synthetics are more tolerant of both heat & shear so it takes longer for the chain of molecules to breakdown, as we are not really pushing the heat limit of a good mineral oil in the RV8 in our case the only real benefit of switching to synthetic is the extended change intervals.

You now need to look at that cost benefit and do your sums, a quality synthetic will typically be 45% more expensive and often much greater than that when compared with a similar quality mineral that carries the same additive package and that essential minimum 1000ppm zinc dithiophosphate. So if switching to a synthetic only extends your oil change interval by 45% more miles or less the truth is you may as well just use that quality mineral because it'll be cheaper and deliver the same performance as the 45% more expensive synthetic.

The regularity of oil changes is a very critical point to consider, in an RV8 running petrol I'd favor a more frequent change schedule using a good quality mineral over extended change periods using synthetic... and the lower price of that quality mineral will allow this. For example if you went with a conservative 3,000 mile oil change using Classic Oils excellent own brand Heritage 20w/50 which is £17.00 for 5 litres you'd need to keep the £52.00 per 5lt Millers CFS 15W60 in the engine for at least 9,000 miles just to achieve the same cost per mile.

Now consider the carbon saturation of the oil at 9,000 miles and you start to see why you're better off just using a good quality mineral oil and changing it out more frequently, carbon itself isn't damaging until it starts to lay down on engine internals causing restrictions in oil galleries and can also limit the correct function of our hydraulic tappets. This is why it's so important to keep the carbon suspended in the oil and synthetics really aren't any better at doing this than a good mineral with a proper detergent package, for this reason and the temperature point I made earlier the RV8 running a good mineral changed between 4-5,000 miles will be a healthier engine than one running a synthetic for double the miles. And don't think you'll be giving you engine better protection if you spend more on the synthetic and adopt the same 4-5,000 mile change interval as the mineral, because it won't, you'll just be wasting money

While we'd all like to think paying more for a synthetic oil will make our engines last longer it really isn't the case, while cost isn't a sexy angle when discussing engine oils on a car enthusiast's forum, when you really understand the true elements that effect oil choice getting the best quality (highest API rating) and the correct additive package for the best value is what we should be looking at, for all the above reasons the synthetic vs mineral debate becomes very much secondary.

Finally you may assume after all that I use a mineral but that's actually not the case, I have done the cost per mile vs quality calculations and settled on a 5,000 mile 7 litre change using 5l of Penrite fully synthetic HPR15w/60 at £33 and topping off the last two litres with Classic Oils mineral own brand Heritage 20w/50. The remaining 3 litres of Heritage 20w/50 gets consumed by the engine over the 5,000 miles so each 5k mile change period costs £33 + £17 = £50. I run a synthetic media Royal Purple 20-253 oil filter which are excellent but admittedly are expensive, synthetic media filters are superior by design having been developed to offer extended 20,000 mile change intervals on hard working diesel commercial vehicles that dirty their oil much faster than any petrol engine car would. Running clean burning LPG I never come close to pushing the capabilities of the 20-253 RP filter so it gets renewed every second oil change IE every 10,000 miles, this makes it little or no more expensive than using a significantly inferior traditional cellulose filter.

In summary, when choosing an engine oil there really is no benefit in running something that's over specified for the application, assuming you choose the right grade of quality oil that has the correct additive package for our RV8 flat tappet engine the frequency you change that oil and the use of a quality of filter becomes the far more important deciding factor.

Price, Performance & Quality = Best Value Engine Protection

Interesting read, thanks. I use the HPR15 in my 500.
What would you recommend based on a time perspective rather than mileage? Say you did limited mileage, would you change the oil regardless after 12 months or stretch this out until more miles have been covered/a greater time had elapsed?

[ChimpOnGas]

GR_TVR said:

Interesting read, thanks. I use the HPR15 in my 500.What would you recommend based on a time perspective rather than mileage? Say you did limited mileage, would you change the oil regardless after 12 months or stretch this out until more miles have been covered/a greater time had elapsed?

Up to a limit of 3 years you really shouldn't get too hung up over oil age, condensation within the engine block and so water contamination of the oil is your biggest enemy here.

In my personal opinion dropping the oil at 2,000 miles just because you reach the 12 month point is wasteful, expensive and really unnecessary. Saying that it's important when you do use the car you get the engine properly hot, if you're only doing short journeys and not allowing the engine to get hot enough to start boiling off the water you are asking for trouble. With this type of use you're also spending a very high percentage of the running time on cold start, rich mixtures create higher levels of carbon and any un-burnt fuel will wash the oil off the bores and dilute the oil in the sump.

If your annual 2,000 miles is covered over 8 good hard unbroken drives of 250 miles each then the 4,000 mile oil change every 2 years would be totally fine.

[GR_TVR]

ChimpOnGas said:

Up to a limit of 3 years you really shouldn't get too hung up over oil age, condensation within the engine block and so water contamination of the oil is your biggest enemy here.

In my personal opinion dropping the oil at 2,000 miles just because you reach the 12 month point is wasteful, expensive and really unnecessary. Saying that it's important when you do use the car you get the engine properly hot, if you're only doing short journeys and not allowing the engine to get hot enough to start boiling off the water you are asking for trouble. With this type of use you're also spending a very high percentage of the running time on cold start, rich mixtures create higher levels of carbon and any un-burnt fuel will wash the oil off the bores and dilute the oil in the sump.

If your annual 2,000 miles is covered over 8 good hard unbroken drives of 250 miles each then the 4,000 mile oil change every 2 years would be totally fine.

Thanks for the info. I've only had the car a few months, but I'd imagine my annual mileage will be 2-3,000 and journeys will generally be 30-100 miles long between stops. Possibly further but only on occasions. I also will imagine I will SORN the car over the winter months, so it'll just be sitting in the garage!
Perhaps yearly oil changes are worth it for me?

[Chimp871]

After 4 miles the oil and coolant are just up to temperature. Whatever you do over this is good for the engine.