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640,000 kms in a Carrera guess which OIL


CarreraG50

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99% of the oil changes have been with regular Castrol GTX... a few Mobil-1 changes around track days. Every 3k miles until 300k, then every 5k miles. Oil change number 120 will happen tomorrow. I've had it since '92, put almost all these miles on myself.

I think I'm on my third clutch disc. The original rubber centered one gave up big time in less than 50k miles. Since then I've put two more in, replacing the flywheel the last time. Not bad considering I mostly start off in second gear.


Other significant maintenance and mods over the last 23 years (I've done all the work myself):

G50 clutch shaft update.
Cam oil line restrictors update.
Front wheel bearings and ball joints (rear bearings are still original).
CV joint boots, these only last 100k miles (CV joints are original).
Worn front crossmember (this was worn at 20k miles!) I put shims in and it's been fine since.
Original alternator failed at 50k miles, replacement is still good. Note this was the ONLY time my 911 stranded me. I put in a volt meter after this to monitor it better than an ammeter idiot light.
Starter failed at 80k miles, high torque replacement been in since then.
AC converted to R134 with bigger condensers and evaporator.
DME cracked the coil solder joints at 200k miles, then not since.
A few DME relays over the years, maybe 2 have failed?
Fuel pump didn't fail, but I replaced a noisy one at some point.
One chain tensioner failed at 350k miles, announcing that with the loud can of marbles sound.
New windshield at 300k miles due to pitting. New one not holding up much better.

http://forums.pelicanparts.com/porsche-911-technical-forum/878284-400k-miles-yea.html

 

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Nice reminder John for us to stop frigging around and just drive these things!

Peter, I have enjoyed your oil threads, there is no one more precious about what oil goes into these car's (Brad Penn 20W50 for the record) than me.

However as you have stated, most good oils will do the trick, as demonstrated above, maybe it's time I gave myself an uppercut and got over my oil snobbery.

(But I don't think I can do GTX )

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640,000km is pretty damn good if the motor is untouched. The high km one in (I think) Classic Porsche mag had been top end rebuilt)

I  still can't figure out why so many of these air cooled Porsches have needed engine rebuilds. Overevved when cold? Too many heat cycles/city driving? Not enough oil changes? An inordinate proportion build on Mondays?

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Peter, I have enjoyed your oil threads, there is no one more precious about what oil goes into these car's (Brad Penn 20W50 for the record) than me.

However as you have stated, most good oils will do the trick, as demonstrated above, maybe it's time I gave myself an uppercut and got over my oil snobbery.

(But I don't think I can do GTX )

LOL!

Don't be to hard on yourself John, I think our intentions are worthy!

Let's remember that this is only one data point and statistically would be regarded as an outlier - a lucky one at that! - and probably shows that driving your car on the highway for hundreds of miles each day isn't necessarily a bad thing.

Just out of curiosity I did a search on his Pelican forum posts and he has used Castrol GTX 10w-40 for 90+% of his 100+ changes.

I can't say I rate Castrol GTX either and looking at the US spec sheets suggests that too.  For example while it is reasonably thick kinematically, it shears dramatically to only 2.9 Mpa.s in the HTHS test.  (Lower HTHS than a modern 5w-30!) .  Appears he chose GTX because it is cheap in the US and he does frequent changes (3,000 miles then extended to 5,000miles)

A little less oil snobbery from me too.

640,000km is pretty damn good if the motor is untouched. The high km one in (I think) Classic Porsche mag had been top end rebuilt)

I  still can't figure out why so many of these air cooled Porsches have needed engine rebuilds. Overevved when cold? Too many heat cycles/city driving? Not enough oil changes? An inordinate proportion build on Mondays?

Taz,

I think it just a matter that they are all show ponys nowadays and perfection is expected. While the engine is out for "resealing",  let's do the heads and chuck a set of rings in too.  Broken a cylinder stud?, let's split the cases and throws some new bearing in it.  Appears money is no object while the engine's out...

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 While the engine is out for "resealing", 

Resealing because the new owner switched to synthetic?

And are the thinner oils worse for cars that sit around in warm climates? The tappety bits etc do dry out.

Gotta keep this thread lubricated!

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Gene Berg used to go on and on (during his presentations) about changing from mineral to synthetic in VW engines. How it changes the ability of the oil to transfer heat, as well as requiring a 'reseal' in alot of engines that start leaking after you change from one to the other.

and i'm not keen on GTX myself either - i'll be sticking with that Penrite stuff

did anyone get to the bottom of what Porsche Classic oil is either? Just rebranded Motul or Liquimoly?

and i wonder how he drives the car? is it always in the city?

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Resealing because the new owner switched to synthetic?

And are the thinner oils worse for cars that sit around in warm climates? The tappety bits etc do dry out.

Early synthetics had a well deserved reputation for causing leaks but I think those days are gone now that elastomer compatibility is tested in the ACEA and the later API test sequences and the oil companies have had to even out the shrink/swell caused by their various products. 

(I can recall changing from conventional to an early Penrite PAO in the nineties in a Nissan Skyline that started to leak within days!  Tightening the cam cover bolts fixed it but was surprised at the on/off nature of the change.)

However if we ever think our air cooled engines are going to be permanently oil tight, I think we are fooling ourselves.  Is there a production engine that has more gasket faces and seals than a Mezger?  I just think its inevitable no matter the oil used.

I haven't come across anything that suggests there is a correlation between viscosity and corrosion/wear in a stored engine.  In my own experience from pulling down engines that they are always well lubricated even if they have been sitting a long long time.

As for synthetic, semi or conventional comparisons I don't think you can do that on any sensible basis as there is no consistent definition of the various types.  I think it's better to forget the chemistry and just compare engine oil on the basis of HTHS and then use the various ACEA/API and manufacturer certifications.

 

Or just use GTX and forget all this oil mumbo jumbo......  

 

  

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