924Board.org

RC · Joined: 25 Mar 2007 Posts: 2637 Location: Australia

Or commonly abbreviated to ZDDP, is an oil additive reputed to be the best at reducing metal to metal friction, wear and galling especially on flat tappets (followers) and camshafts, such as those in all 924`s, 2.0L, turbo, and 924S 2.5L.

Critical for the reliability and longevity of our engines valvetrain it has been the optimal preferred additive by oil manufacturers over the years. Still is, however due to the progressively recent EPA regulations affecting OEM producers regarding catalytic converter service life, this vital component has been reduced successively over recent years.

An accepted level of ZDDP was 1400 PPM (0.14%) at the time our cars were built, and appropriate grade oil was indeed specified by Porsche, API SE or better. Depends on the definition of better. Modern oil is now API SM specification. The ZDDP content is regulated at < 800 PPM (0.08%). Better for marginally extended cat life, debatable improvement in fuel economy, and dramatically better at chewing up our cams and followers. Practically all modern engines manufactured to use this grade are twin cam multi valve, with quite low spring pressures and usually running roller lifters or followers.

How many members have experienced cam and lifter problems in recent years? Very interested to hear from those who may have had their car for many years, especially from new. For the more mature members, can you recall many valve train failures in the early days, 70`s and 80`s? on Porsches or Chevvies if it comes to that. Or is it a predominantly modern phenomenon?

Personally believe so as do numerous engine builders, cam manufacturers and poor owners. Keen to hear others experiences, good or bad, not necessarily opinions on oil brand A,B or X rather on zinc dialkyl dithiosphosphate and its relative content.

http://www.lnengineering.com/oil.html#Z13

http://streetrodder.automotive.com/72322/0803sr-modern-engine-oil/questions.html

http://streetrodder.automotive.com/72322/0803sr-modern-engine-oil/questions.html

Min · Posted: Sun Feb 08, 2009 9:28 am Post subject:

This perked my interest, is there a additive we can just add to our oil to give us higher levels of zddp?

Min
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Custom means it didn't come from a box.
1980 n/a with EDIS and Megasquirt II Injection. 7 different colors and counting.

ic932 · Joined: 11 Feb 2005 Posts: 1104 Location: UK

I've encountered a few ORIGINAL 924Turbo owners that have come back to the fold, (now 944 owners...boo hiss)...anyway, all have showed genuine interest in my 931 projects but both have critizied the 924Turbo for "not lasting long before re-build" (These are first time 931 owners from new). If oil technology has moved so far forward over the years than great...Snake oil, much like banana skins helps the imagination lol. Does rasta need banana skins?...well, white guys calling themselves "rasta" hmmm, know a few Jamaican lads that would........

emoore924 · Joined: 13 Apr 2004 Posts: 2822

I use a zddp additive from cam-shield. They have "testimonial" type info on their website.

Here's the link:

http://www.cam-shield.com/

Ths info regarding this product initially came to me via Hagerty Insurance magazine.

No affiliation, etc., but I have had no cam/follower problems since I started using, and for +$7 an oil change, worth it as far as I'm concerned...

ideola · Joined: 01 Oct 2004 Posts: 15550 Location: Spring Lake MI

Here's another ZDDP additive offered by Bill Hirsch Automotive:

Smoothie · Posted: Thu Jun 04, 2009 2:24 am Post subject:

More discussion on the topic here - http://www.924board.org/viewtopic.php?t=24352

Somewhere along the line, after becoming aware of the situation, I read that diesel truck oils still contain higher levels of ZDDP, and switched to this - http://www.mobil.com/USA-English/Lubes/PDS/GLXXENPVLMOMobil1_Turbo_Diesel_Truck_5W-40.asp
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"..it's made in Germany. You know the Germans always make good stuff."

'82 924T, US version, dark green metallic, 5 speed Audi 016G gearbox

ideola · Joined: 01 Oct 2004 Posts: 15550 Location: Spring Lake MI

Some of the Mobil1 links in that other thread are now dead, but here's an interesting table from the Mobil1 site, listing the phosphorus content of their product range:
http://www.mobiloil.com/USA-English/MotorOil/Files/Mobil_1_Product_Guide.pdf

According to the chart, M1 15W50 has 1300 PPM of ZDDP, and is listed as being suitable for performance, racing and classic applications. I'm breathing a bit easier since this is what I've been running in ALL of my cars.
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erstwhile owner of just about every 924 variant ever made

Vince Ponz · Joined: 02 Nov 2002 Posts: 3581 Location: Florida

As an original owner of a 77 1/2 I changed the cam in 82 and never had any problem with the car. For ten years heavy track time still no problem. Changed oil after every track event. Carbs drain gas into oil therefore I change it often. Cheap fix. Large jets
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"Never let them see you sweat"
77.5 924 modified track car
79 931 Euro stock
88 924S SE
87 911 Targa stock

Min · Posted: Thu Jun 04, 2009 3:06 pm Post subject:

turns out you can buy a zddp additive right from GM http://www.slantsix.org/articles/Modern_Engine_Oils.htm under p/n 1052367 in the US, 992869 in Canada. Your local gm dealer will have it in stock.

Min
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Custom means it didn't come from a box.
1980 n/a with EDIS and Megasquirt II Injection. 7 different colors and counting.

Arominus · Posted: Fri Jun 05, 2009 3:36 am Post subject:

I've been running synthetic Rotella T 5w-40w to get my ZDDP fix, the diesel oils have not cut back on the additive.
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1987 924s

loosehead · Joined: 20 Apr 2009 Posts: 10 Location: PA, west of Philly

Eastwood is a pretty good company for the restoration folks

They carry it too:

http://www.eastwood.com/catalogsearch/result/?q=oil+additive&x=8&y=13

LH
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'79 924 -- just purchased

RC · Joined: 25 Mar 2007 Posts: 2637 Location: Australia

The old debate regarding oil additives was running well prior to the days of my grandfather working on Spitfire engines during WW2. Additive manufacturers and sellers telling us their product is needed for all kinds of reasons while the oil companies inform us consumers that their oil is complete and nothing else is required and is in fact detrimental.

Although there is likely some truth in both POVs its difficult to separate the science from the hype. However there`s no escaping the fact that our engines were designed to use ZDDP to extend top end life and that modern oils meeting modern specifications simply do not contain the necessary quantity.

Additives vary from very high quality produced by specialist tribologists at major oil companies to backyard purveyors of diluted snake oil. As well as the percentage of zinc and phosphorus required to bring the total to 1400 PPM or more, what else is in the bottle and how compatible is it with the base oil being used?

A quick look at some of the additives mentioned above show its a case of hit or miss unless you know the percentage breakdown of your base oil and am prepared to do some calculations.

Cam-shield give no concentration and after 4 pages write:

Min · Posted: Sat Jun 06, 2009 11:37 am Post subject:

Power Tryp · Joined: 16 Apr 2009 Posts: 435 Location: Calgary, Alberta

Looks like I'm going to have to get my leak looked after and then change to an oil that has what we need, thanks for this guys I probably would have wrecked my motor if this board wasn't on it's game like this.

Tryp
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Melanie - 1980 931
NoName - 1980 931 (seeking rebuild)

Green tartan interior, you don't see that on a Civic.

Raceboy · Joined: 01 Mar 2004 Posts: 2327 Location: Estonia, Europe

On a race-car I use Motul 300V 20W60, on a street car usually Motul semi-synthetic.

300V is one of the best oils you can find and it has higher ZDDP levels. Here's some info: http://www.p1-performance.com/pdf/oildoc.pdf
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'83 924 2.6 16v Turbo, 470hp
'67 911 2.4S hotrod
'90 944 S2 Cabriolet
'78 924 Carrera GT replica
'84 928 S, sold
'91 944 S2, sold
'82 924S/931 "Gulf", sold

'84 924, turbocharged, sold.
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