gbgastowers

This is the best if you can find it.

andy-gts

after yrs of lurking I gather Torco or Brad Penn is the standard, nothing wrong with Amsoil either..(full synthetic)

hacker-pschorr

I was an RP user about 10 years ago. It's just too damn expensive for a street car.

Alan

I now run Amsoil 20W50 and the car likes it a lot better in the heat than the Mobil 1 15W50.

2 Bar now at all times - even hot summer idle.

Alan

hacker-pschorr

Some would argue that means the Amsoil doesn't flow as well as the Mobil 1

Threads like this one is exactly why auto makers stopped putting oil pressure gauges in cars.

The steps Todd is taking on my new motor will reduce oil pressure.....but it will greatly increase flow to the bearings. This has been discussed in great detail in many threads, but usually get's lost in all the Kibort's.

An easy way to insure you always have good oil pressure is to reduce the size of the oil passageways to the crank the next time you have the pan down. I'm not saying this is a good idea, but it will guarantee you maintain pressure.

JoeTaylor

Casterol GTX 20W50..

Alan

Maybe you are right... but my rod bearings didn't like the Mobil1 - wear was evident, so I changed all those - that alone may also have helped with the pressure. Anyway I'm happy with the new combo. I did already swap the sensor, oil thermostat, oil bypass valve, clean the cooler, add a series oil/water cooler... all chasing this down.

Running at <1 bar hot idle and getting pressure warnings every day is not viable in my book (Phoenix summer heat running). Something had to be done - its running well now and oil ingestion seems lower too.

Alan

dogleg

[QUOTE=Hilton;8917649]Simple..

1. Look in your owners manual
2. Select the recommended weight for your climate range (likely 20W50)
3. Identify locally available oils in that weight
4. Figure out which of the locally available oils has >1100ppm of ZDDP in it

fell on the first hurdle here!no owners manaul with my 30 yo car unfortunately must look out for one of those, it would be good to have one.not planning on using this car through winter so i now feel confident using the 20w50.thanks to all who replied.

andy-gts

Is it true that "STP" oil treatment is zddp.....if so choose oil and add stp oil treatment

NoVector

No kidding - amsoil $10.20 a quart(?) WTF-Over? $20 wipper blades, $35 air filters, $40 distributor cap, $90 an hour service fee... somebody wake me up.

http://www.amsoil.com/catalog.aspx?GroupID=173

Speedtoys

Ive been eyeing Cam Guard..not a bad idea at all for long parked cars either.

FredR

You will probably get as many answers on this one as you get posts. The only common answer that most would agree on is the need for adequate zinc content. I am a bit wary of oil that has been standing for a long time. Lube oil is a blend of a number of components-principally base stock and additives and what happens when these blends sit for a long time and whether they settle and/or re-blend correctly when worked I have no idea and I am a chemical engineer in the oil industry. If the oil has been standing for more than two years I would be inclined to dump it but there is no engineering science to that opinion and I am pretty sure the components will not degrade in that time frame.

With respect to grade of oil I think the first question you should ask is what oil was available at the time the car was produced? Not too many synth's were available for automobiles in 1981- [initially they were the realm of jet engines] and you would probably struggle to get anything that was not 20w50 mineral based in a multigrade formulation.

Another false perception is with respect to oil pressure. Contrary to what most seem to think, oil pressure is not really needed to secure lubrication- but it is needed to transport the lube into a position where it can lubricate. Once the lube is in position it is film strength that counts. Lubrication is a "you either have it or you do not" type of concept. Once you have sufficient lubricity, having twice as much serves no purpose. Viscosity is [or was] a critical performance indicator but not so much the case these days as lubes with relatively low viscosity can lubricate satisfactorily [more so with synths]. For optimal efficiency low viscosity [thus reduced drag losses] is desired. Low viscosity is also desirable in that it will enhance the rate at which the lube oil flows around the system at any given pressure thus help enhance cooling.

The consensus these days is that it is cold start conditions that do most harm to engines and a 20w50 is pretty thick at 0 C. Not a problem where I am but in the UK??? Synthetics invariably leave the engine cleaner and have improved lubrication grade for grade but they also seem to find leak paths easier and the engine will burn more than a similar grade mineral oil.

For my purposes in a hot climate my favorite oil is Redline 20w50. I cannot source this recently so currently use Castrol GTX 20w50 [lowest oil consumption I have seen]. If I was on the track I think I would want the Redline on board. In the Uk for road I would use the GTX during summer but not so sure about winter- perhaps something lighter [10w40?] to ensure the oil circulates better on cold starts. Either way whatever oil you use the zinc component seems to be critical for our flat tappet engines.

Finally, technology has not stood still and all lubricants benefit from superior additive packages than they did 20 or even 10 years ago. You may well find that even a "Halfords special" is better than anything that was available in 1981.

Regards

Fred R

vanster

I use Castrol GTX 10w40 as I am from the school that in the late 70's ( when the 16 valve was designed) synthetics were not used nor spec'd.
I have used Amsoil in my Alfa race motor which seemed to be the ticket. Race motors are built to beat and run hot.
I don't hammer my 928 every time I drive it . Also as we all know the first 90 seconds of operation on any motor is the hardest
so why in normal climates use a 20w50 as you need as much viscosity as quickly as possible. A good high quality dino oil per the manual should be Ok. Also per the manual the oil change cycle is 15,000 miles.
Frequent changes may not be all that beneficial.
Van

dogleg

A good high quality dino oil per the manual should be Ok. Also per the manual the oil change cycle is 15,000 miles.
Frequent changes may not be all that beneficial.
Van[/QUOTE]

wow 15,000 miles could that be right?? i wouldnt leave any vehicle that long between changes.think 6k mls is normal for most cars.

Cosmo Kramer

If you want a couple of days reading do a search of engine oil in the 928 forum.