ALKada

dcrasta

I try to keep it close to the top notch. [on the stick] . I check it hot, on level ground. If im checking it cold I want it right at the top line or slightly higher.


I use the Rotella or Castrol GTX 20/50.

I drive every day , rush hour traffic, stop and go, and highway combined.

Temps get over 90 in the summer here (at least).

Winter I switch to 15w40 Rotella.

I think you Op looks normal to me -Pyzik

What really important is frequent oil and filter changes. I change every 5k miles and change filter every other time. If the oil is black or really dark change it more frequently.

dprantl

Anything less than a 50W oil when warm in a 928 is a

Dan
'91 928GT S/C 475hp/460lb.ft

antlee928

Whilst only having owned a 928 for a short period of time (12 months), I have discussed the matter of suitable oil for a 928 with many people including those people who run service shops that specialise in 928s and other front engined Porsches and especially those cars that run flat tappets such as the 928. The consenus is this is a "last Century" engine that was designed to run on those oils avaiulable at the period and specifically as described in the owners manual. Here in Oz and for the temperature ranges we see here the strongest recommendation is for 20W50 and, more specifically, an oil that contains sufficient ZDDP (Zinc - normally more than 1000ppm) to minimise engine, tappett and bearing where in the engine. One shop in paricular here in Australia has been using such oils in the many 928s they service here and has also been keeping records on wear, etc. They have also been keeping records on engines that come in with problems and have been known to be running thinneroils and oils with known lesser quantity of ZDDP. Whilst this was not scientific, his records show that 928s (irrespective of engine size and model) all benefit from 20W50 with ZDDP of more than 1000. Now, of course, the question of oil has always been quite topical and, in some cases, been the cause of raging debates. For my money, this is a last century engine designed to run reliably and with longevity based on the manufacturers recommendations. I'm sticking with a good quality 20W50 with known high levels of ZDDP which I am confident will give me long engine life. Oh, the other thing to do is regular/frequent oil changes. I do it at least every 10,000kms including an oil filter each time. I taken a similar approach on my 300HP (modified) Saab 9000 Aero MY97 which I purchased ion 1998 with just 5000kms. It now has around 300,000km with no problems. I use the recommended oil and do regular oil changes and filter changes. Frequent changes + good quality oil (you get what you pay for) = happy and durable engine!

Many of the oils around today must comply with later standards such as API SM & SN which limit the amount of ZDDP to only around 600-800ppm. There are many in the industry that believe this is to low for our older engine technologies and that a minimum of 1000ppm (per the older API SH & SI standards of the late '80s/early'90s) is required to mitigate against wear. To increase ZDDP levels in oils one can use an additive like molybdenum (not molybdenum disulphide). Look for an oil that has a ZDDP of at least 1000ppm and you should be right. Ideally you still want to use an oil designed for older engines/higher mileage engines and that still complies with API SH & SI to have reasonable certainty of ZDDP levels.

The other thing to remember is that oil companies do modify/change their formulations from time-to-time (often to comply with new standards) so the same oil you were using say 5-10 years ago may not be the same formulation as today.

So to summarise the above:

1. Good quality oil with minimum ZDDP of 1000ppm (check for API SH & SI compliance)
2. Frequent/regular oil changes usually no longer than 10,000km - 6,200 miles - but also based on driving conditions e.g. more frequent if lots of city, start/stop and hi engine temp conditions versus lots of highway/freeway, cooler engine temp driving conditions
3. Always change the oil filter and use a good quality oil filter (I use Mahle)

Racing oild tend to have much higher levels of ZDDP. Typically 1200ppm or more. I wonder why \:-|

Here's a good read on the Zinc myths, http://www.penriteoil.com.au/technical_bulletins.php. This is not to be taken of an endorsement of this company's products (although they are quite good). There are some other related good technical bulletins here also.

BTW, the same can be said for other 928 fluids such as coolant, transmission, brake but obviously on a less frequent cycle.

.........i'm done...........

Happy motoring

Pyzik

Great info , thanks alot ! I just chose my oil according to this .

waynestrutt

Check this part 92810717902 for scoring or other wear plus adjoining parts . Because if it jams, sticks or has a build up of crud the pressure will dump and ???? The filter also has a relief valve that will bypass the element if the factory setting is wrong or if the filter is full of crud. Additives like STP or other thickeners are too thick for the fine holes in the wrist pin and plug it causing wristpin failure. !.5 bar /22psi at idle hot is fine ,sure higher is nice but as long as you can still have 2.5 /36psi to 4 /60 psi hot when at full song your in good shape.

Pyzik

My oils p sits at 1.5 but when I sat in traffic last night for 15 min the "!". Would flash twice together with the oil pressure light , after 3 min it did it again , and my oil level is good . Pressure switch??

robot808

Thank god, an oil thread!!!
Pyzik, I use 15/50 M1 most of the time, with no problems. I would probably use 20/50 if it were easier to find. (I'm somewhat lazy)

antlee928

Pyzik, oil pressure senders do fail and also become lazy over time. It's a relatively simple and accessible change to replace. Just need a short arm shifter that will fit into the available space. I had a sender unit that was reading low after I change oil. I thought it was the oild viscosity I was using (15W60 - Penrite). I changed oil again after about a week with 20W50 - Valvoline MaxLife) but still same. Took it to my 928 indie who got the pressure meter out and did a proper test. Oil pressure just fine, guage just fine. So by logocal deduction it must be the sender unit. Sure enough I got a pressure sender unit from Roger and installed and now reads fine. NB: the in vehicle oil pressure guages tend not to be accurate and should only be used as a guide to oil pressure. Normally, and with the recommended oil viscosity, the gauge should show a "hard" 5psi when engine is cold at idle and certainly 5psi when warmed up and at highway speeds and RPMs over 1500-2000rpm. When hot (heat soaked) the gauge should be showing around 2psi an certainly nothing less than 1 psi.

Suggest you have your service shop check actual oil pressure and be prepared for sender unit replacement.

Cheers

Daniel Dudley

Rotella T6 is great oil. I run 20/50 in my car, and I think Valvoline VR1 racing is a good oil for dino oil. I think Amsoil is an excellent choice, and I don't think Mark is wrong about that. Can't go wrong with Redline or Royal Purple either.

I am not a big fan of Mobil one in 928s or 911s. The 911 boys all swear by Brad Penn, a great oil. Lots of people use the M1 oil, but I have heard way too many stories about it to be really confident about it in my own cars. It is absolutely true that you need zinc (ZDDP) in a 32 valve car, esp the GT and the 85/early 86 cars to protect the cams.

FWIW, Kibort may be a little OC about Amsoil, but that doesn't make it a bad oil, or make him in any way wrong about it's qualities. He did run the **** out of his engine using it, and I expect that it my have anti foaming qualities that keep it in the sump and doing it's job. A lot of the 951 boys think that anti foaming is a big contributor to rod bearing survival. Keep in mind that I myself am not a doctor, nor do I play one on TV.

Also consider that sometimes some pretty creepy ''engine'' noises can come from a defective filter. Doesn't seem like this would be one of those cases, but it can happen. Merlin is right about pulling the sump, as he usually is, but of course checking the filter is the litmus test.

Keep us posted on what you find in your filter Mark. I would be interested to know.

Pyzik

Today after driving the car for about an hour the oil pressure would sit at 1 bar , not 1.5 anymore. The pressure light blinks almost everything I start driving if I don't use gas pedal to start moving just let slowly the clutch pedal , I can make it blink at a parked position with parking brake applied , on first gear without pressing the gas pedal, check out the video. Is it safe to drive ? Also I noticed some oil on driver side distributor where the plug wires plug in , would that be cousing the low pressure ?

http://www.youtube.com/watch?v=lP54xrn48ao&feature=youtube_gdata_player


http://www.youtube.com/watch?v=fCSp5FDfU_k&feature=youtube_gdata_player

GlenL

More oil story...

I put the used Amsoil racing 20w50 from my 928 and 944 into my 1973 Buick Riviera which has a 455. That would really quiet the lifters compared to 10w40 organic oil especially at start-up. Seems to make the engine run more quietly, too.

Well...

That big block started making disturbing cracking sounds and is sidelined awaiting and engine pull for proper analysis. Rod bearing? Broken rod? Something really bad happened.

Dougs951S

hmm..seems unlikely that oil of that grade would be too thick for that motor, but I am interested to know what happened. My vote is rod bearing.

brutus

The ONLY good thing about oil threads is everyone has an opinion ! Yet very few know what the numbers on the bottle actually mean. Doug Hillary did a wonderful long term oil evaluation with lab testing of the oils, a very good read. One point he learned was that it takes 15 minutes of driving to get the oil up to normal operating temp in his S-4.

Mike Frye

Dude