Andre The Giant

Hi Everyone,

After reading many posts on motor oil and what type to use with viscocity ratings, I am quite confused, since I get mixed information, see this:

In this post : https://rennlist.com/forums/928-foru...t-and-gts.html
They say this:
In a general sense;
Mineral Oils (Porsche suggest a minimum of a Group 3 synthetic from MY84)
1 - For 16v engines a 15W-50 viscosity lubricant is a good all year round choice
A 15W-40 HDEO can be used too – see “NOTE 2” below.
A 20W-50 mineral oil should be a last choice and only in a suitable ambient temperature range
(Note that 25W-50 or 10W-60 etc oils should NOT be used in your 928's engine)

2 - For 32v engines 10W-40 or 5W-40 viscosity lubricants are good all year round choice
A 15W-40 HDEO can be used too – see “NOTE 2” below
A 15W-50 should be a last choice
(Note that 25w-50 or 10w-60 etc oils should NOT be used in your 928's engine unless racing)

Synthetic Oils (Group 3 (hydro-cracked), Group 4 (PAO) and Group 5 (Ester))
Porsche issued TISBs in 1992 and just prior to the cessation of production - and again in 2004, and specified a Group 3 synthetic 5w-40 grade A3/B3 lubricant as a minimum requirement

3 - For 16v engines a 15W-50 lubricant is a good all round choice
A 5W-40 petrol engine lubricant or an HDEO can be used too
A 20W-50 should be the last choice
4 – For 32v engines a 5W-40 (or 10W-40) lubricant is a good all round choice
A 5W-40 HDEO can be used too
A 15W-50 should be the last choice
(Note that unless racing 10W-60 synthetic oils should NOT be used in your 928's engine)
---------------------------------------------------

Then the owners manual specify this: Screen capture

For my usage 20w50 would be best since I want to use a synthetic motor oil.

In this line they say :

A 15W-50 should be the last choice for a 32V engine like mine
Is it that grade exactly, or will it include all ?W50

Since I live in the great white north, Near the capital, Ottawa, I only drive it during spring/summer to sometimes November, depending on when the snow starts.

Can anybody clear this up for me.

mike77

The first number W should only affect the cold start viscosity. Once #W50 is up to temperature the weight of the oil is the same. A lower W rating should be better in colder climates as the oil will flow better when cold.

Also I'm pretty sure15W50 is synthetic and 20w50 is dino

Edit: just checked, here in the UK 15W50 all appears to be synthetic but it also only appears to be marketed at motorcycles. So what I've stated above may be not true there.

davek9

I really tried to resist posting to yet another "what" oil type thread, there are WAY too many, please do a search.
However I'll just quickly add this:
When your manual was written the types of oil suggested didn't consider that newer/future oils would or would not contain the additives needed for FLAT tappet engines like the 928.

So in short, which ever oil viscosity you select for your climate and driving style you must look for one that is formulated for Flat Tappet engines.
You can also add an additive to the oil of your choice to achieve this.

potdog

Hi if 10/60 is ok for B.M.W M cars its ok by me drive them hard all ways .

davek9

that is too general of a question to answer, there are way many M cars over the years.

Andre The Giant

Thank you Dave. I will keep this in mind " you must look for one that is formulated for Flat Tappet engines."

I have read so many articles lately about type, grade and viscosity ratings of oil, that I am thoroughly confused.

I will continue my research before I do my oil change this spring. So far I hear so many different comments, that I am tempted to talk to Porsche directly to get it from the "horse's mouth" ! LOL

Since I will only be lucky enough to have owned one Porsche, a MY 85, I am trying to make it last as long as possible without any engine issues caused by excessive wear on engine parts.

Thank you again.

davek9

Your most welcome, please try this link for the correct ZDDP levels

https://rennlist.com/forums/928-foru...highlight=zddp

Dave

Andre The Giant

Thank you everyone, it seems I have found my oil, Royal Purple HPS 20w50. I have sent them an email yesterday and asked them for the levels of ZDDP in this oil and they responded with 1200ppm, Bingo. Then they went on to say that it's not the only thing that constitutes a good oil, correct but for our engine with flat tappets it is crucial.

bureau13

I was going to go with Amsoil Z-Rod or the Brad Penn 20w50, but maybe I'll add this to my list of potential oils. I used to use it in my RX-8 (despite some weird synthetic oil controversy) and liked it.

Andre The Giant

Here is the reply from Royal Purple:

On 2/19/2015 5:45 PM, James Morrissey wrote:
Good afternoon Andre,

For your 1985 Porsche 928 5.0L V8, Royal Purple HPS 20W-50 (part #31250, quart bottle) or Royal Purple HPS 10W-40 (part #31140, quart bottle) are excellent choices for your engine oil.
HPS: http://www.royalpurpleconsumer.com/p...hps-motor-oil/

Parts per million(PPM) of ZDDP has to be calculated because the ZDDP anti wear additive is a chemical compound, not an element. The ZDDP compound is primarily made up of the elements zinc and phosphorous. So, in an elemental analysis of an oil sample, ZDDP shows up mostly as separate zinc and phosphorous numbers. Typical/nominal batches of Royal Purple HPS oils will be in excess of 1200ppm zinc and phosphorous each. So by adding the zinc and phosphorous together the ZDDP can be roughly inferred.

While zinc and phosphorous anti wear additives do matter, they are not the be all-end all of oil protection. I would like to encourage you not to get too caught up in zinc and phosphorous numbers alone because it simply does not determine a superior oil. Our proprietary Synerlec additive is something the other companies have not been able to copy and accounts for much of our legendary film strength advantages and high temperature oxidation resistance.
Synerlec: http://royalpurpleconsumer.com/about...rple/synerlec/

Thanks for choosing Royal Purple and have a great day!

Best Regards,

James Morrissey
Sr. Automotive Technical Support
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p 281 354 8600 f 281 354 7600
e jmorissey@royalpurple.com
One Royal Purple Lane Porter, TX 77365
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From: Andre
Sent: Thursday, February 19, 2015 3:35 PM
To: rpautotech
Subject: Message sent to Consumer Product & Technical Information-Automotive, Motorcycle, Marine or Racing from RoyalPurpleConsumer.com

Name: Andre Viau

Hello, I am preparing to do my spring oil change in my 1985 Porsche 928 with the 32V 5.0L engine which has flat tappets and was wondering what are the levels of ZDDP (Zync and Phosphorus ) in your HPS motor oil. I am looking at the synthetic 20w50 grade since this car is only used from spring to late fall, depending on snow fall here in Ottawa, Ontario Canada ?

How many PPM of ZDDP is in your product ?

hwyengr

People think oil threads are controversial here....man. Spend any time at all on a rotary board, not just viscosity and type, but whether or not to pre-mix 2-stroke oil into the gas.

Miss my 8, don't miss those boards.

bureau13

Ha ha ha, yes, the oil conversations here are a bit more laid back!

Andre The Giant

It's hard to find a good oil with high levels of ZDDP here in Ottawa/Gatineau region of Canada. I am possibly considering buying Castrol Edge synthetic in the 20w50 if they have it or 15w40 and adding this product to my oil change, what do you think ?

http://www.hyperlube.com/c3/Zinc-Rep...ditive-c7.html

Kevin in Atlanta

I found this on eBay: 5 Gallon Royal Purple 20w50 Synthetic Motor Oil 05250 for $136 with free shipping.

Andre The Giant

Thank you Kevin. The only problem is many places do not ship to Canada and on top of this my wife tells me our passports have expired in November, so until we get new passports I can't even get them shipped to Ogdensburg and go pick it up either !