Engine Oil

[edh]

I think we have 2 different (maybe 3) audiences here - ones who are most concerned with track performance (Patrick), where oils get very hot (and thin), others who want a good oil for road use (Edd), where the car is likely to do more short journeys, and maybe a third (Rob) where the engine may be using / losing a significant amount of oil. This means that there is more than 1 "right" answer. My biggest concern with 0w or 5w oils on a road car would be their propensity to leak/seep when the engine is cold. In normal road use these engines are very strong and reliable. Regular changes of any decent mineral or synth oil should work fine IMHO. There are many more pressing issues to worry about on a 20 year old car than oil grade.

 

[Copperman05]

ORIGINAL: edh There are many more pressing issues to worry about on a 20 year old car than oil grade.

Maybe, but talking oil grade is fun. Isnt it?[&:] Ed you are right of course, different uses calls for different oils. I'm sure we will be discussing the finer points of oil for many years to come and the different opinions will undoubtedly remain. Edd

 

[edh]

All part of "the game" I think Edd [] BTW - I tried out some valvoline racing 10w60 semi synth recently - not as good on track as my favourite synth oils as pressure dropped off significantly once the temps went over 110 degrees.

 

[oilman]

ORIGINAL: robwright Guy, Could you email me a price list for your oils to see how they stack up to my local factor please mate. I think I might go for the Silkolene. It seems to come highly reccomended. When I make the change I take it that is adviseable to do the filter also? I noramlly would be looking at filter every 12 and oil dropped every 6. Current filter has been in around 3 months. Cheers, Rob

Rob, All prices are on my site here [link=http://www.opieoils.co.uk]http://www.opieoils.co.uk[/link] and you get 10% club discount, plus any offers we have on top, and there are offers on all the time. The Pro S would make a very good top choice. Cheers Guy

 

[oilman]

ORIGINAL: 333pg333 Curious how significant the supposed charged particles in Magnatec cling to our Alusil cylinders? I'm in agreement with Thom. I wouldn't put a 10w/40 anywhere near my engine let alone a 5w/40. Remember that the Porsche manual recommends a mineral based Multigrade oil of 20w/50 down to below freezing temps (-10oC)...and this was on cars as recent as some 996 models. For those of you that really care about what you put in your engine, here is a most excellent and detailed thread that is relevant to our 'flat tappet' motors. One of the main contributors on this topic, Charles Navarro is a leading expert in this field. I have saved this thread and return to it semi regularly. [link=http://forums.pelicanparts.com/porsche-911-technical-forum/367300-ultimate-motor-oil-thread-why-we-hate-cj4-sm-oils.html]http://forums.pelicanparts.com/porsche-911-technical-forum/367300-ultimate-motor-oil-thread-why-we-hate-cj4-sm-oils.html[/link] http://tinyurl.com/yzrxn2t

The only reason I would put a 20w-50 in one is if the engine is very worn or in a very hot climate... Like where you are. In the uk SAE40 or SAE50 with 5w 10w is ideal or for the hardened track goers 15w. Cheers Guy

 

[TTM]

Since wear is the only relevant data we should agree on, we would need to know, for a given type of oil, how much wear occurs during a "cold" start up and how much wear occurs when the engine is already "warmed-up" and is actually being run in given running conditions. However I'm not sure 944s are at their best when used as shopping trolleys []

 

[oilman]

There are lots of factors and variables to this, state of the engine? State of tune of the engine? Type of oil used? How long the oil has been in there? The temp the oil has been running at? You will just go round and round in circles trying to pin down one answer. Cheers Guy

 

[edh]

ORIGINAL: TTM However I'm not sure 944s are at their best when used as shopping trolleys []

I see you have the "shopping" model as well as the "performance" variant []

 

[Diver944]

ORIGINAL: oilman You will just go round and round in circles trying to pin down one answer.

Yup it's what we do Often

 

[robwright]

Well guys I hope this thread hasn't lost the plot. It was certainly not my intention for it to do so [] I will apologise for posting about oil her in the first instance as I did not know oilman's technical article existed. If I can say it has been entertaining to say the least. Believe it or not it is also comforting to know that so many of you care so passionately about your cars and indeed what you put in it!! Would we be having the same conversation about a Ford Mundano? I think not. In response to my original post I think I will just have to live with the oil usage for now and accept it as a consequence of increased boost and a child like need for speed [] I will however be swapping to a fully synth oil probably Silkolene Pro S - a 10W40 me thinks. God I hope this doesn't set everyone off again lol [] Thanks again for your responses. Rest assured I have read everyone of them. It's good to know you guys care. Oilman thanks for the price list - shall have a good look later.

 

[sawood12]

ORIGINAL: 333pg333 Curious how significant the supposed charged particles in Magnatec cling to our Alusil cylinders?

The oil doesn't cling to the alusil cylinders but it does cling to the wearing surfaces of the cams, bearings in the engine and all the ferrous metal surfaces the oil comes into contact with. Ester oils are no gimmick. They are the only thing that can be used with modern gas turbine engines as when those things start up they spin up very quickly for a good 30 seconds or so before they start up and oil starts to circulate properly through the engine so they need adequate protection during that phase hence the use of Ester oils. Unlubricated bearings will last a few seconds in a gas turbine enigne unless properly lubricated so that is how effective Ester oils are. The oils Porsche recommended for our cars 20yrs ago took into account the state of the art in oil technology of the day. That was 20yrs ago and things have moved on significantly. If Silkolene Pro was around 20yrs ago i'm sure Porsche would have spec'd it. Also i've said it before and i'll say it again - thicker oils (i.e. oils that are too thick) offer less protection - not more. A thick oil doesn't flow as well as a thin oil. Oil pressure is not a measure of adequate oil flow over the moving surfaces. You restrict flow you reduce the lubrication effect of oil and reduce the cooling effect the oil has. Use the oil viscosities Porsche recommended irrespective of milage or age. 5w40 - 15w50 has been proven to be a perfectly safe and fine viscosity range for oils in the UK climate for normal street use. Also don't scrimp on oil. £40 for a decent can of top quality oil is cheap on a cost per mile basis. We put a higher value of petrol in our cars every 300 - 350 miles.

 

[333pg333]

ORIGINAL: Copperman05 Yes thats the table I was talking about, thanks. At the bottom Porsche recommends, yes thats right 'Recommends', using 5W-40 oil for all season use, it lists it as a fuel economy oil as it is a synthetic oil which provides less drag and therefore improves fuel economy slightly. This oil is superior to mineral oil, and is a 'high performance oil' porsches words not mine. 5W-40 is the same viscosity as 10w-40 15W-40 20W-40 at working temperature, so it is not like water as you suggest but exactly the same viscosity at working temp as the other oils, the only difference is the cold weather temperature viscosity. Your assumption that thick oil is better becasue it doesnt drain down into the sump is incorrect and this it not how oils are designed to be used. Thin oils are BETTER at start up because they are thin, thick oils are less effective at low temps, this is common fact. A thin oil is able to be pumped around the engine much quicker at low temps lubricating the engine, a thick oil takes much longer to circulate and therefore more wear occurs. Notice on the graph you have posted that as temperatures get lower the recommended oil viscosities also get lower, I'm not just making this up... Edd

As far as we can determine, Porsche only ever used the term 'High Performance' oil in one year's manual. The mechanic that I use who is a front engined specialist went through a number of manuals and we couldn't ever find those oils that you favour termed any else but 'Fuel Economy' oils. I think it was a typo personally. [] No, the thick oil doesn't attach itself to the top end just because it's thick, but it does tend to leave much more of a film on the aforementioned parts. While I agree that in general the temps we see down here are going to be higher than yours, the fact that the Owner's manual suggests usiing 20w/50 down to below freezing is good enough for me. Plus I get the advantages off the extra protection that a 5/w40 is not going to give. It doesn't have to be on the track either. Stop start traffic in Summer will do it. I use a 25w/60 for the track. As far as the graph recommending lower visc oils the lower the ambient temps, well sure, but do you drive your car in temps lower than -10oC? The overriding factor in our choices are based on how many 944/951 motors we know that have 'blown' and almost all of them have been using lighter visc oils...and that's not just in Australia.

 

[sawood12]

Hang on a second - the chart posted on the first page says that a 20w40 is good between ambient temps between -10 to over 40 degs - I think that just about covers the UK climate and a lower W viscosity is only going to extend that temp range futher into the lower minus temps. On this basis a 5w40 - 15w50 is going to be more than adequate. Also bear in mind that modern fully synthetic oils are more viscously stable relateive to temperature than a 20yr old oil and will last longer - you could probably get away with a 0w30 for a street car. An ester oil is only going to add to the cold start protection capability of the oil - which at the end of the day is the most important feature of an oil as all the wear of an engine occurs in the first 10mins or so over every journey - once the oil is upto temp there is zero wear occuring - so it is all about your ratio of starts to mileage. A 60 grade is way way too thick for anything other than a race car or a car that is tracked by a very accomplished driver (much like yourself Pat!!) who will be able to get the oil temps high enough for the 60 grade to reduce to an effective 40ish.

 

[944Turbo]

15W50 for me and my car gets driven hard on road and track (though not managed it for a while), we never see temps as low as -10 in the south though. Oil pressure very very rarely drops to 3.0 bar even at idle on trackdays. Silkolene ProR or mobil 1 motorsport are my preferred oil, though currently trying a millers motorsport. Castrol magnatec is not magnetic so why shouldn't it stick to Alusil as well as it sticks to anything else - wouldn't use it myself though. Tony

 

[944Turbo]

ORIGINAL: sawood12

]Hang on a second - the chart posted on the first page says that a 20w40 is good between ambient temps between -10 to over 40 degs - I think that just about covers the UK climate and a lower W viscosity is only going to extend that temp range futher into the lower minus temps

. Yes but on track or a hard run you are going to get the engine very hot - it is accepted the oil cooler is slightly marginal, so you will get more heat than planned, I prefer the extra protection at the top end of the range. Tony

 

[Neil Haughey]

15W-50 Mobil 1 for me in the S2 for the past few years and 10W-40 Mobil S in the 968. TBH the thinner oil in the 968 is noticeable as in cold weather the S2 seems slower to crank over, it was faster when I ran it on thinner oil. Main thing for me is I seem to suffer less oil loss in the S2 with the thicker oil. That engine has done over 170K miles though. The 968 is used all year round so for me the cheaper Mobil S makes sense as I changed it recently and will change again at the end of winter. For the season next year I will probably buy a job lot of the valvoline VR-1 race oil, the stuff with the very high ZDDP content, linky: http://forums.pelicanparts.com/porsche-911-technical-forum/459139-zddp-notice-vavoline.html

 

[Copperman05]

ORIGINAL: 333pg333 I think it was a typo personally. []

Come on its not a typo stop bending the facts to suit your argument, these oils Porsche talk about are fully synthetic oils, they are called high performance oils because synthetic oils ARE high performance oils. Its that easy!! Edd

 

[Copperman05]

For what its worth, I run 5W-40 in my S2 and I get 3.5 bar at warm idle, the engine uses very little oil (I dont need to top up between servicing) the engine does not leak and the seals are just fine. Granted it is fairly low mileage for the age at 97,000 which may a help but I run 5W-40 in my car as it offers the best balance of protection for the type of use it gets. It seems to me that soemone writes an article regarding oil and viscosity and it becomes a bible everyone hangs on every word when in reality its not 100% accurate. There are alot of myths regarding oil, sorting the truth from fiction is not easy. Edd

 

[333pg333]

ORIGINAL: Copperman05

ORIGINAL: 333pg333 I think it was a typo personally. []

Come on its not a typo stop bending the facts to suit your argument, these oils Porsche talk about are fully synthetic oils, they are called high performance oils because synthetic oils ARE high performance oils. Its that easy!! Edd

Not bending any facts. Seems like you're the only one who is getting bent out of shape re this discussion. The FACT that in a multitude of front engine Owner's manuals they clearly state your favoured oils as 'Fuel Economy Oils' seems to elude you. As far as them being High Performance oils, well I'm not sure on your definition of a H.P.O., but you won't find race cars using this weight oil, especially 944/951 race cars. Of course it's up to you what you use and in certain cases I don't see any real harm in an English environment based on certain driving habits, but I can only be guided by people that know a hell of a lot more than you or I. In other words, experts. You clearly have your beliefs and more power to you, but to suggest I'm skewing the facts to suit my point of view is untrue. As for myths surrounding oils, that's correct. The marketing depts of not only the oil companies but also the car companies are largely to blame. The fact that everyone seemed to be sucked into the M1 myth and they reduced their levels of ZDDP without telling anyone is a case in point. They seem to be addressing this problem recently. Probably due to the amount of backlash they were receiving in the marketplace. Many engines were showing high rates of excessive wear or worse. Many mechanics were moving to other brands yet there will always be people that are swayed by the millions of dollars poured into the marketing of said product and refuse to see the truth.

 

[333pg333]

ORIGINAL: sawood12 Hang on a second - the chart posted on the first page says that a 20w40 is good between ambient temps between -10 to over 40 degs - I think that just about covers the UK climate and a lower W viscosity is only going to extend that temp range futher into the lower minus temps. On this basis a 5w40 - 15w50 is going to be more than adequate. Also bear in mind that modern fully synthetic oils are more viscously stable relateive to temperature than a 20yr old oil and will last longer - you could probably get away with a 0w30 for a street car. An ester oil is only going to add to the cold start protection capability of the oil - which at the end of the day is the most important feature of an oil as all the wear of an engine occurs in the first 10mins or so over every journey - once the oil is upto temp there is zero wear occuring - so it is all about your ratio of starts to mileage. A 60 grade is way way too thick for anything other than a race car or a car that is tracked by a very accomplished driver (much like yourself Pat!!) who will be able to get the oil temps high enough for the 60 grade to reduce to an effective 40ish.

Exactly. At least you're starting with a base W of 40.