[Peter B]

I've not been adding ZDDP.  From the forum, it looks like adding ZDDP is a good idea, but how much.  The manufacturer recommends 4-5 Oz in each oil change.  What are the dangers of adding too much?   I don't want my camshaft and other moving parts to get too worn!

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[94SilverCab]

Since our 968s take 6 Quarts of oil, as opposed to typical 5 Quarts for US cars, I would think you would be safe with 4-5 Oz. recommendation. Hopefully, other mechanically inclined members will opine.

 

Jay

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[ds968]

I understand that in addition to all the other compelling reasons to use Amsoil, it also ( reportedly ) contains the greatest amount of ZDDP of any other synthetic oil brands , so the 6 quarts our cars take should add up to an optimum / sufficient level of ZDDP.

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[MLB]

Mobil 1, 15W50 also has the highest level of any mobil 1 product, and I think it's the right amount for our flat tappet engine. It has come up before on the forum.

My recollection is the risk of adding too much is about fouling the (NLA) catalytic converter sooner.

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[Kim]

Yes, that's what Pete told me when I had my car down to his shop for work on the head.

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[Chris Vais]

My PM has me using Total conventional racing oil which has a higher level of zinc additives that feels are correct for engines. The shop I go to has a lot of experience with these cars, including competition experience.

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[Waylander]

You need around 1200 PPM

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[MLB]

https://mobiloil.com/~/media/amer/us/pvl...-guide.pdf


Yep, mobil1 15W50 has:

1200 ppm phosphorus

1300 ppm zinc

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[Peter B]

I read in an oil related discussion that the 5-15W50 oils tend to have more zinc.  The lighter weights have less.  With a 12 ppm target , there is a guide.  I can't find a good spec sheet from Pentosin - theirs only talks about certifications.  The zinc could be part of the certification specs.  

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[flash]

additives are never as good as getting the oil with things already in it.  i would change to an oil with the correct amount to begin with.  amsoil is by far one of the best oils out there.  pricey, but then so are rings.

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[Rap]

I use a 15/50

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[ds968]

According to a well known and highly reputable Ferrari / Maserati repair and engine rebuilding shop , ZDDP for all of its benefits, is also known to have one major adverse effect ; it's the biggest cause of destroying catalytic converters. But this is in reference to 8 cyl and 12 cyl engines, so no clue if aluminum 4 cyl engines burn oil very differently so the exhaust gases going through the cat are materially different as well ?

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