Engine Oil
- Thread starter Billygoat
- Start date
Copperman05
New member
Thats good if your saving money spent on oil but does having a thicker oil that gives less oil consumption actually a good thing, or does it just appear to be a good thing as less oil is being used? I mean is the thinker oil actually doing a better job than the thinner oil, or is just less of it being used? Why is less of it being used? Because its too thick to get burnt off as much as a thinner oil? Does that make it better at doing the job asked of it?
Edd
Edd
Having had the head of my engine at various mileages and circa 100k hard miles (some on track with slicks / sticky treaded rubber) by me on top of the 90k it had when I bought it, I would say the thicker oil works fine right up until the point you wash it out of the bores with too much fuel - not sure the thinner oil would be any better in this respect however.
Tony
Tony
sawood12
New member
I think the key phrase in Marks post is 'Driven Hard'. When driven hard oil temps increase, viscosities decrease therefore the oil will thin. On 5w40 my old 944 hardly used a drop of oil for normal street driving - it would go between oil changes without needing a top up and use about half the distance between max and min on the dipstick. But on trackdays i'd be topping the oil up after every session on track (about 15 mins). Clearly if I was heavily tracking the car a higher grade of oil would be prudent. In anycase 15w50 is still within the Porsche recommended range.
ChasR
New member
Ah, the old 'thinner oil is better' comment.
Stick 0W40 in a Mazda Rotary and see how long the engine lasts
. I know in a 944 engine it doesn't help in the slightest. Although to be fair when my old engine had 0W40 in it (previous owner thought the engine had a stuck tappet) it did hold the oil pressure at 2.5bar when warm (driven for quite a while) and 5ish when on the run but as said gauges are not the most accurate of things in the world. It did however start to pee oil out of the crank seal not many months after it was put in, in addition to the lingering smell of oil.
It's not about what's the thinnest but moreso about what is suited to the job in hand. In the case of some forum members here, they are from France and Australia, two relatively different climates when compared to the UK.
Tolerances have more to do with things than people appreciate. In some of the rebuilt BL engines I've seen they seem to appreciate running more on a 20W50 than they do on a 15W40 (where the oil pressure gets lower than spec in even an Ivor Searle rebuilt engine with next to no miles). The Porsche is no different IMO (although I understand the pistons to bore tolerances are closer than people than people think).
FWIW, I ran my last engine on 15W40 semi (it was on its last legs though) and my current one is on 10W40. I'm toying with going to 15W50 if I take up track days though.
Stick 0W40 in a Mazda Rotary and see how long the engine lasts
. I know in a 944 engine it doesn't help in the slightest. Although to be fair when my old engine had 0W40 in it (previous owner thought the engine had a stuck tappet) it did hold the oil pressure at 2.5bar when warm (driven for quite a while) and 5ish when on the run but as said gauges are not the most accurate of things in the world. It did however start to pee oil out of the crank seal not many months after it was put in, in addition to the lingering smell of oil.It's not about what's the thinnest but moreso about what is suited to the job in hand. In the case of some forum members here, they are from France and Australia, two relatively different climates when compared to the UK.
Tolerances have more to do with things than people appreciate. In some of the rebuilt BL engines I've seen they seem to appreciate running more on a 20W50 than they do on a 15W40 (where the oil pressure gets lower than spec in even an Ivor Searle rebuilt engine with next to no miles). The Porsche is no different IMO (although I understand the pistons to bore tolerances are closer than people than people think).
FWIW, I ran my last engine on 15W40 semi (it was on its last legs though) and my current one is on 10W40. I'm toying with going to 15W50 if I take up track days though.
Tony, why are you getting cylinder wash on the track?
What a lot of people are missing (and this is from heavy traffic driving to track work) is that the oil is there not only to provide a lubricant and act as a coolant, but also to actually help prevent those expensive metal engine internals from colliding and destroying each other. As most of you would know the tolerances we are dealing with are sometimes % of fractions. Quite simply, having a higher weight oil that doesn't break down and get too thin under heat is offering greater protection than some of these very light weight oils that are being bandied about. Remember that the Porsche owner's manual right up to some 996's were recommending a 20w/50 mineral based oil amongst others. Sure some of the others would have been lighter weight 'synthetic' marketed oils but they are still given the option. Also we recognise that these oils won't give quite as good fuel economy as others, but again, that's something most Porsche owners wouldn't have at the top of their list of priorities.
Was mostly on the road and down to a faulty temp sensor, I knew it was running rich - well very rich, the black smoke was very visible in the rear view mirror, but at the time needed to do lots of miles quickly with little time to investigate. result was circa 170k miles with immaculate bores and around 15k to destroy one of them. Problem is now fixed but a little late. Will need to sort the engine soon, trying to decide whether to go with a standard unit or an audi TT V6, still havent measured one - though one of the articles here suggested it might bolt up to a 924 torque tube the 5cylinder does and I heard a rumour the V8 does.
Dont know yet if the back end of a 924 torque tube will bolt up to a 944 gearbox, but imagine if not a hybrid tube is relatively easy.
May decide just to get the original engine rebuilt, but either way need more time at home than I am currently managing.
Dont know yet if the back end of a 924 torque tube will bolt up to a 944 gearbox, but imagine if not a hybrid tube is relatively easy.
May decide just to get the original engine rebuilt, but either way need more time at home than I am currently managing.
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