Yet Another Zinc Oil Question

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4,030
Location
WA
Originally Posted by paoester
Originally Posted by Mad_Hatter
SN rated lubes for pcmo's are gonna have the zinc capped no matter the brand. Find a diesel 10w30 like Motorcraft Super Duty if you want higher zinc.
Not 40 and 50 weight ones. Example: Mobil1 15w50 is SN and has high zddp, 1200 ppm, up there high. Cheap in 5 quart jugs at walmart. (The M1 0w40 at walmart would also work well in this application, another SN oil at 1000 ppm zddp, somewhat high.)
You are correct, anything above a 10w30 (like race oils) is exempt from the low phosphorus requirements of API SM/SN. If the OP wants to run a 10w30 with high zinc, a diesel oil is gonna be his best bet IMO. Or find some pre API SM oil south of the border....
 
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13,194
Location
Maricopa Arizona
Originally Posted by JeffKeryk
No offense meant, but your question is impossible to answer unless the valve spring pressure rate is taken into consideration. A good 10w30 might do the trick or a boutique oil might be required. If I ever pull apart one of my classics again I will stab a roller and be done with it. Here is a great post from the C3 Corvette Forum. Flat Tappet Cam Oils
It's a stock cam. Off the shelf motor oil is beyond sufficient if the car isn't tracked.
 
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1,771
Location
South Carolina
Originally Posted by dave1251
Originally Posted by JeffKeryk
No offense meant, but your question is impossible to answer unless the valve spring pressure rate is taken into consideration. A good 10w30 might do the trick or a boutique oil might be required. If I ever pull apart one of my classics again I will stab a roller and be done with it. Here is a great post from the C3 Corvette Forum. Flat Tappet Cam Oils
It's a stock cam. Off the shelf motor oil is beyond sufficient if the car isn't tracked.
That's my point. As ZDDP content goes up, so does the friction coefficient. Therefore, I want the least amount of ZDDP that'll get the job done.
 
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35,625
Location
NY
Originally Posted by RDY4WAR
Originally Posted by dave1251
Originally Posted by JeffKeryk
No offense meant, but your question is impossible to answer unless the valve spring pressure rate is taken into consideration. A good 10w30 might do the trick or a boutique oil might be required. If I ever pull apart one of my classics again I will stab a roller and be done with it. Here is a great post from the C3 Corvette Forum. Flat Tappet Cam Oils
It's a stock cam. Off the shelf motor oil is beyond sufficient if the car isn't tracked.
That's my point. As ZDDP content goes up, so does the friction coefficient. Therefore, I want the least amount of ZDDP that'll get the job done.
At what point in ppm is ZDDP harmful to an engine? My bet is well over 1,200-1,400 ppm which is a target some people strive for with older engines.
 
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1,771
Location
South Carolina
Originally Posted by demarpaint
At what point in ppm is ZDDP harmful to an engine? My bet is well over 1,200-1,400 ppm which is a target some people strive for with older engines.
Typically ~3%wt (~1920 ppm Zn). The friction becomes so great that it actually becomes abrasive.
 
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35,625
Location
NY
Originally Posted by RDY4WAR
Originally Posted by demarpaint
At what point in ppm is ZDDP harmful to an engine? My bet is well over 1,200-1,400 ppm which is a target some people strive for with older engines.
Typically ~3%wt (~1920 ppm Zn). The friction becomes so great that it actually becomes abrasive.
Thanks.
 
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35,625
Location
NY
Originally Posted by dave1251
Why would anyone want 1200-1400 PPM of ZDDP? That amount wasn't common until the 70's.
It pops up here from time to time, in fact extra ZDDP is what this thread is about. I felt today was as good a time as any to ask.
 
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1,771
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South Carolina
Don't forget that ZDDP isn't just one additive but a group of additives. Not all ZDDPs are created equal. We know far more about how ZDDPs work now than we did in the 70s.
 
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4,030
Location
WA
Too much can also turn the oil acidic. This graphic plus link is from Driven.. obviously there's more wear with no zinc, then there's the sweet spot and beyond that you get into abrasive/corrosive wear due to excessive zinc. More is not always better as they say. Driven - Zinc [Linked Image]
 
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24
Location
usa
Originally Posted by Tedd
Originally Posted by ka9mnx
You do not need .... ZDDP in that engine.
You're probably right. But, it's also at least possible that you're wrong. If it's all the same to you, I'd like to use an oil containing zinc, even if I "know" it's not necessary. It won't hurt anything, other than maybe my wallet. See where I'm goin' with that?
not sure if you meant that literally... but ALL modern oils still contain zinc or zddp. the levels have been reduced from pre SM levels but they all have usually a minimum of ~800ppm. also modern oils use improved types of ZDDp that they claim last longer than older stuff so higher levels are not needed to do the same thing. valvoline also states their oils contain a longer lasting zddp so doesnt need super high levels, plus additives like moly etc are anti wear. as mentioned above, just because its a flat tappet lfter engine does not mean it needs ultra high levels, if the cam/lifters are stock & the valve springs are stock or close to stock ratings then you dont need specialty oils like bradd penn or vr-q etc. the whole zddp craze is more for racers or engines with "big" cam lift & duration that requires heavy valve springs.. just because its an "old" engine does not mean it needs 1000-1200+ ppm of zddp.
 
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