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Typical rule of thump is 10 psi per 1000 rpm min oil pressure.
I'd pull the filter and sump and make sure you didn't do any damage. Might be worth while to do a used oil analysis to make sure you didn't damage the main/rod bearings.
Then I would put a new oil pressure relief spring/piston assembly in the oil pump. They do go bad from time to time.
Thanx for that tip Alvarado, but I did drop the pan and checked out the strainer, and replaced the spring and piston, the piston was the updated one with the beveled edge but the spring was the same, I read in some other forums that the new updated spring was a bit longer and stronger, I can't tell if my original one was changed by either of the previous 2 owners, according to all the work invoices not one indicates a changed spring.
I've notice that now after the car has rested for a few days the oil pressure drops to the .5 bar sooner then before, oil temp gets to bearly 180 degrees and at idle the pressure needle rests at .5 bar, I'm going to hook up a mechanical gauge this morning and compair dash cause and mechanical, hope the luck is with me...
As Charles mentioned earlier that 10 psi per 1k rpm is minium?
I read somewhere that 1 bar is 14.7 psi then .5 bar is 7.35, and my 997.1 idles at 7.? K , I'm a bit lower then what might be safe, calculation wise?
Thanx for that tip Alvarado, but I did drop the pan and checked out the strainer, and replaced the spring and piston, the piston was the updated one with the beveled edge but the spring was the same, I read in some other forums that the new updated spring was a bit longer and stronger, I can't tell if my original one was changed by either of the previous 2 owners, according to all the work invoices not one indicates a changed spring.
I've notice that now after the car has rested for a few days the oil pressure drops to the .5 bar sooner then before, oil temp gets to bearly 180 degrees and at idle the pressure needle rests at .5 bar, I'm going to hook up a mechanical gauge this morning and compair dash cause and mechanical, hope the luck is with me...
When was the oil last changed and what oil is in it? You might consider going to a 15w50 to see if that helps any. Stock filter? Do you know if the car was tracked previously at all?
The oil only has about 500 miles, I have mobile 1 0w40, but I did try other oils to see if any differance, I do use the OEM oil filter and the other oils I've tried are Motul 5w40, Mobile 1 5w50, and so far all three of these oils have the exact same behaviour, to day I'm going to try the Castrol Edge 5w40 apparently it's also on the porsche A40 list.
The engine sounds great , it has nice pickup for having 110k miles on it, after it's hot it does have that little ticking sound that keeps pace with the engine RPM.
I was thinking of sending a sample of the oil to the lab but the oil change prier to this one I put in a oil additive to loosen any sludge and clean lifters, I think I could still smell a little of the cleaner when I open the oil cap.
Is there any truth to the fact that it would take more then a couple of oil changes before seeing a differance?
also I'm wondering if a scavenger pump not getting the oil back to the sump might be an issue...
The oil only has about 500 miles, I have mobile 1 0w40, but I did try other oils to see if any differance, I do use the OEM oil filter and the other oils I've tried are Motul 5w40, Mobile 1 5w50, and so far all three of these oils have the exact same behaviour, to day I'm going to try the Castrol Edge 5w40 apparently it's also on the porsche A40 list.
The engine sounds great , it has nice pickup for having 110k miles on it, after it's hot it does have that little ticking sound that keeps pace with the engine RPM.
I was thinking of sending a sample of the oil to the lab but the oil change prier to this one I put in a oil additive to loosen any sludge and clean lifters, I think I could still smell a little of the cleaner when I open the oil cap.
Is there any truth to the fact that it would take more then a couple of oil changes before seeing a differance?
also I'm wondering if a scavenger pump not getting the oil back to the sump might be an issue...
In my experience, engine flush products tend to cause more problems than they solve. Instead of using them, I would advise several oil changes with a cheap 10w40 non-synthetic oil in close succession.
You'll need at least 1000 miles on the oil for used oil analysis to give you any useful results, but having the oil tested would be a good idea.
With the pressure being so low and if you've already replaced the pressure relief, I would possibly try a 5w50 or 15w50 full synthetic to see if the higher viscosity improve the hot low idle oil pressure and if the noise you are describing lessens.
With the pressure being so low and if you've already replaced the pressure relief, I would possibly try a 5w50 or 15w50 full synthetic to see if the higher viscosity improve the hot low idle oil pressure and if the noise you are describing lessens.
Hello,
This is a good answer and an easy way to fix your potential problem with the oil PSI alone- 225F oil temps I think are part of your problem as your oil will be at a 5W30 essentially. The operating temp oil grade on the bottle is measured at 212F. Viscosity decreases as temperatures increase.
That being said, there are many factors when considering oil pressure changes and going to a higher viscosity, you sacrifice one thing for another- oil flow being the main thing so it is a fine balance. See picture below taken from online which is a good representation:
I would recommend trying our Sport 5W50 vs a 15W50 as there could be issues with the operation of the variable timing valve-train with such a high cold temp viscosity/grade as well as the flow of the oil at cold temps vs a 5W. The Motul Sport is based on group 5 synthetic esters for increased engine lubrication vs grp 3/4 synthetics and are known to help with engine oil related temperature issues. It will also have a nice dose of friction modifiers (moly) for increased power and engine component efficiency/protection. - Nick
Hello,
This is a good answer and an easy way to fix your potential problem with the oil PSI alone- 225F oil temps I think are part of your problem as your oil will be at a 5W30 essentially. The operating temp oil grade on the bottle is measured at 212F. Viscosity decreases as temperatures increase.
That being said, there are many factors when considering oil pressure changes and going to a higher viscosity, you sacrifice one thing for another- oil flow being the main thing so it is a fine balance. See picture below taken from online which is a good representation:
I would recommend trying our Sport 5W50 vs a 15W50 as there could be issues with the operation of the variable timing valve-train with such a high cold temp viscosity/grade as well as the flow of the oil at cold temps vs a 5W. The Motul Sport is based on group 5 synthetic esters for increased engine lubrication vs grp 3/4 synthetics and are known to help with engine oil related temperature issues. It will also have a nice dose of friction modifiers (moly) for increased power and engine component efficiency/protection. - Nick
Thanks for jumping in here Nick. Is this the mixed use street/track oil? What intervals have you found are safe with this product? At what oil temperature would you say the 5w50 would be more appropriate than the 5w40 viscosity? For example, the 987.2 and 981 engines will see on an 85F day oil temps as high as 280F in a 30 minute DE session.
Thanks for jumping in here Nick. Is this the mixed use street/track oil? What intervals have you found are safe with this product? At what oil temperature would you say the 5w50 would be more appropriate than the 5w40 viscosity? For example, the 987.2 and 981 engines will see on an 85F day oil temps as high as 280F in a 30 minute DE session.
Hi Charles,
Yes, the Sport is the product that's between the Porsche approved 8100 oils and the motorsport 300V line. 7500 miles looks to be a good window for street use depending on the application etc. If you're doing a mix of a track day or 2 while also driving it on the street, start with a 5,000 mile drain interval and go from there. You guys do have a large oil sump after all! The only true way to tell is doing a UOA, that would be my suggestion for maximizing the drain interval and gives you some insight if changes need to be made.
Those are pretty short intervals at those temperatures so I wouldn't overreact and go to a 5W50. Now if it's repeated use and long stints at 285, going to a 5W50 wouldn't be a bad idea. It's not really about X temperature you should move up in viscosity, it would be more about how long that temperature is being seen and the type of product being used. Hence my response to the OP's post about low oil PSI, high'ish oil temps every time he drives etc. That would warrant more of change than 30 min sessions on a track.-Nick
Is it advisable to mix Motul DCTF with the Pentosin fluid that is used by Porsche? I would like to use the DCTF at the next service of my PDK.
Hello there,
No problem- both are virtually the same viscosity (a mongrade 75W gear oil). Our DCTF does have a quite a bit higher viscosity index vs the Pentosin FFL-3 so it will be a nice upgrade over the factory stuff -Nick
@Nick - this is awesome info. Its great to have you in the community!
Motul 8100 5w40 was recommended to me by the shop doing my PPI and I have used it for 15k miles. The prior owner had Pentosin High Performance. The Blackstone numbers showed a solid improvement after switching to Motul, improved viscosity at 210 and increased Zinc and Phosphorous. I also no longer heard the lifters on colder mornings in San Francisco, which I would hear with the prior oil. However it seemed to run hotter and idle at a lower oil pressure. (I stress "seemed" because I wasn't paying attention as much when I first bought the car.) On Motul I run highway at 205-210 oil temp and get up to 225 regularly with any load. Oil pressure at idle is around 1 bar at 200 oil temp. Ive seen it drop below 1 when temps got up to 240 ripping through some mountains.
My indy is a Porsche race shop and recommended I switch to a Swepco, a non-sythentic every mechanic there swears by. I was reluctant but figured they know more than me. They started me at 15w40 as a baseline and then want me to move up to 15w50 if I see no change. Ive seen maybe a 5-7 degree temp decrease with no change in pressure. I do hear slightly more lifter noise, which I assume is because of the 15w.
A couple questions for you...
1. Jake Raby made a comment in a thread that Motul ran hotter than other oils, second only to Redline. Any truth to this?
2. Can oil weight have any effect on oil temp, or just its viscosity.
3. Where do I find your 50 weight oil you mentioned above? I couldn't find any in your 8100 line, which is partly why I decided to try out Swepco.
06-15-2018, 04:27 PM
