hacker-pschorr

+1

Our local tuning shop and his engine builder have been testing Brad Penn on a couple of "high stress" engines. Long story short they now stock it.

I'll be switching my 928's to BP for 2010, actually since four of my cars use 15w-50 in the summer I'll probably change the whole fleet over.
Except the SAAB, sticking with Redline because of the turbo and the known sludge issue.......

Herman A

Why is it so very important to use oils with high contents of ZDDP (Zink Dialkyl Ditio Phosphate) in Porsche V8s? Are there some recommendations from Porsche or any reports about worn cam lobes for engines which have not been using oils with high ZDDP content, or is the need just a myth?

ZDDP is an additive which shall protect oil lubricated surfaces from wear. It exists as 2-15% of the quantity of the sum of all additives. SM classified oils hold ~0.08% ZDDP and already such low contents will prevent seizure. There are no evidences that the earlier appearing SJ and SL classified oils automatically have higher content of the additive than SM oils and therefore automatically will provide better protection. It varies among brands and even among products of the same brand.

ZDDP contains chemical compositions of phosphor and zink. Too high contents of these will over time hurt catalytic converters.

The problem which I am aware of is when SM classified oils are used in old American pushrod engines. Does anyone have some camshaft and tappet wear reports for Porsche V8s which have been run with low ZDDP-conten oils?

dprantl

Correct me if I'm wrong, but the only multi-grade 50W oil Brad Penn makes is 20W-50. IMO the 20 is too high for climates that get to freezing temperatures, so it is not an option for me. Also, it is listed as a "partial" synthetic, whatever that means.

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

Lizard928

The GT cams are known to pit. Most that I have seen have normal wear with nothing excessive.

However there is also some 16V 928s that have seen cam failures which some have pointed out could be caused by too much friction.

I think most look at it in a "better safe than sorry" mode.

hacker-pschorr

See Greg's post above - it's because of the flat tappet lifters, no other reason. If the 928 had roller lifters this would not be an issue. ZDDP is an excellent cushion in high pressure areas, like where the camshaft pushes on the lifter in our cars.

Very few (if any) performance cars are produced today with flat tappet lifters / cams.


If you are running your car in cold enough weather, a 40 blend should work fine, no?
Your only other option is 15w-50 which isn’t much difference or 5w-50 which I would never run in my 928, not from any manufacturer.

Doesn’t the manual list Xw-40 in cold weather?

I thought it was 100% non-synthetic. I’ll have to check into that.

With frequent oil changes I’m not worried about running a full synthetic or any synthetic.

Herman A

Yes, I know the effect of ZDDP and have described it in my post. Roller lifters belong mostly to V8s of US origin.

Many, if not the majority of engines made in Europe and Japan use flat buckets with cam lobes just above. At least the more powerful BMW engines must be classified as beeing very high performance and I've never heard about any high ZDDP recommendations for these. Higher content of ZDDP doesn’t hurt other than what I’ve described in my post. If there are no recommendations from Porsche or evidences for Porsche V8 engine failures caused by normal ZDDP content, I am very sceptical about the need for high-content ZDDP oils in Porsche V8s or in any other engine with similar camshaft/bucket design, unless it is explicitly mentioned by the manufacturers.

hacker-pschorr

Gotcha....I guess you are under the assumption Porsche is actively testing and making oil recommendations for an engine they stopped producing in 1995.

I highly doubt it since they could care less if critical parts like rubber fuel lines are no longer available, much less what kind of oil we dump in.

Fact is, ZDDP is being phased out of oil for emission reasons since it kills catalytic converters. Neither of my 928's have one so it's of no concern to me.

This discussion is really a moot point since every Xw-50 oil that I know of has the "old" levels of ZDDP and is the viscosity of choice for the 928.

As for Euro motors with flat tappet lifters, funny how brands like LiquiMoly are very popular due to their higher (than GF-4 standards) ZDDP.
Same goes for Japan, where the very popular oil with the performance / track crowd is Nippon brand Eneos, which is touted as having high ZDDP levels.

All that aside, I'm going to listen to the experience of someone like Greg Brown about my 928 engine more so than Porsche who has very little to no interest in my car.

Why does it have to be a Porsche V8 to be a valid reason to use ZDDP? Any engine with flat tappet cams would suffice for me (Yes I have seen evidence with non-928 engines with flat tappet lifters)

Anyway, to answer your question, yes, there have been reports of excessive cam / lifter wear with 928 engines with GF-4 and or SM rated oils.

danglerb

Why Zinc is important.

http://www.youtube.com/watch?v=oAJ4XVmI4dc

Herman A

This is your assumption, not mine. Porsche have for their V8’s recommended oils by defining viscosity ranges and API/ACEA classifications. Besides the latest API class SM oils, SJ and SL types are still available. ZDDP content generally, but not always decrease by later alphabetical order of the letter x in Sx. API SM and ILSAC GF-4 oils are according to both, fully backwards compatible and designed to provide BETTER wear protection than previous classified oils. These oils must pass the Sequence III test which includes a sliding tappet test. Modified engines or fully race built engines might have protection requirements which are larger than the SM/GF-4 requirements. Special oils are therefore available. However, I don’t believe that the majority of the 928 V8’s belong to these categories.

If an oil is popular among non-racing car users is not necessary correlated to the performance of the product but to many other factors such as visibility on the market, pricing etc. For people doing racing and which rebuild their engines now and then, I agree that they will be able to analyze if one product works better than another. LiquiMoly declare in their safety data sheets for some of their oils, ZDDP contents in the several percent range. How they manage to sell these oils to the majority of users which have cars with cat’s, without telling them about the consequences is hard to understand.

There is absolutely nothing wrong with using high ZDDP oils in any type of engine. I’m just questioning the evidences which prove the need. I have also seen the described wear in other engines but not at all drawn the conclusion that it is the API SM classification of the oils which cause the problem. There are so many others which can have influence.

I understand that you and Colin have observed cam lobe and bucket wear on 928 V8’s. Are you convinced that the wear is caused by the use of SM or GF-4 oils and nothing else? Have the problems appeared after this type of oils have been introduced in:
- standard engines with normal street use
- engines with highly modified cams
- racing engines
- high mileage standard engines
- engines which before have been run wih less good oil quality, long oil change intervals etc
- engines with new cams and lifters and where the problem disappears with the same new components plus high content ZDDP oils

It is one thing to observe an effect and to make a correlation (find a dependence) and a much more difficult task to describe the causality (cause and effect).

turbochad

+2 for Brad Penn. It is half the price of Mobil 1 and twice the oil for our cars. And as it relates to cold climates, go out to your car and look at the 928 owners manual which recommends 20-50W down to 0 deg F. I am in Denver and I never drive my 928 during the 10 days a year that we hit that temp anyway. I keep BP 20-50 in my shark year round. It is great stuff and yes it is partially synthetic and partially Pennsylvania Crude stock, the best there is. It is readily available in most areas and I buy it retail at Hill Petroleum for $45 a case.

jcorenman

You are correct, I have no direct evidence that lower ZDDP levels will damage our engines. Nor do I have any great desire to find out.

I appreciate the discussion, friendly debate is always educational. But asking a question is not a valid reason to use a lower ZDDP level than was in general use when our engines were designed and tested.

The oil spec in the 1990 owner's manual was for API class SE or SF oils, 20w50 down to -10C, dino or synthetic. ZDDP levels for pre-SJ oils were generally in the 1200 ppm range. Prudent engineering dictates sticking as close as possible to that spec, unless there is some clear advantage to a change.

The only advantage to lower ZDDP levels is potentially less long-term damage to the cats, and that only if the engine is burning oil. AFAIK there has been no evidence and no testing, it is just something that the EPA thought was a "good idea".

bogdan

I've used Castrol RS (TWS in the US) 10W60 in all my previous cars with great succes. Over the years I used many fully synth oil brands, the last experience being with the "mighty" Mobil1 5W50 that destroyed two rod bearings in my vw scirocco(DD car not racing). My personal observation is that the RS significantly reduces friction as the oil temps are lower and the engine revs somewhat quicker, also the mileage is better by a small amount. Last summer I put this stuff in my '91 GT (70K mls) and the lowest oil pressure in hot days and stop/go traffic was 3bar (previously had 2bars idle with 10W40 synth). I know this doesn't equals flow capacity of an oil but is just my observation...

Rick Carter

I didn't see any info on foaming with BP. I need to get a garage sale blender and do some testing.

slate blue

By jcorenman

Couldn't agree more, on the cats issue, it i.e ZDDP may damage the cheaper cats but the cats with the good metals in them seem unaffected according to a local specialist. This may just be a scare campaign also, the damage done to cats will be a cheaper if it happens to fix, than a new engine. I think it probably goes further than just sliding wear too. It is probably all metal to metal surfaces, we just don't see it, or notice it because it is on the minor side. In higher milage engines it will be evident.

Greg

Glen McCartney

Just came home from a auto swap meet here in Allentown. Mostly street rod stuff, but there was a company there selling a zddp additive called cam shield. The web site is www.cam-shield.com. Talked with the rep a little. He said most oils even the ones with the highest levels of zddp don't have levels that compare with what was in oil in the 80's and 90's. He said the levels in the oils with zddp at most have 1200ppm. He said that the Mobil 1 15-50 is at that level. Most racing oils have high levels, but he said most racing oils don't have the level of detergents that are best for street cars.

I bought a bottle, enough for 32 quarts of oil, figured it can't hurt, it was only $24.00., Not worried about cats...they're gone.