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View Full Version : Zinc ZDDP, roller or flat tappet



travis85904
06-21-2015, 03:53 PM
Hey, so i heard that when doing an oil change in these older cars, if you use a full synthetic as i do, that you should be adding ZDDP zinc, and phosphorus because of the flat tapett camshaft. Does anyone know if the a20a3 motor is like this? and should i be using the zddp and phosphorus additive?

Hauntd ca3
06-21-2015, 10:00 PM
just use a high mileage oil

Oldblueaccord
06-22-2015, 04:30 AM
Hey, so i heard that when doing an oil change in these older cars, if you use a full synthetic as i do, that you should be adding ZDDP zinc, and phosphorus because of the flat tapett camshaft. Does anyone know if the a20a3 motor is like this? and should i be using the zddp and phosphorus additive?


That's for cars that use hydraulic lifters our cars do not use lifters at all. General statement but most American V8 pre 1985 use flat hydraulic lifters.

Our Honda motor is an overhead cam design with direct rocker arm action from the cam to the valve tip.

ZDDP would not hurt but its not necessary.

gp02a0083
06-22-2015, 08:42 AM
not really required with today's roller setups, mainly this is a concern for older engine designs with flat tappets. Current industry standards for SN conventional oil have the metal content around 900 ppm, which may be a bit low. When our engines were designed they met the SF to SG/SH API classifications. However you mention you are using full synthetic, most of these have average spec around 1000ppm (typically see 800-1200 ppm). I believe you are fine in that regard. I want to mention about the additional additives you buy separate, in my opinion don't buy additives that you add to the oil. They tend to still settle out (look at zmax's instructions, must have engine warm and running when adding product.). Oils that are specifically blended with the additives would be a better choice. Otherwise mobil1, valvoline and shell have decent amounts of the metal components you are asking about. ( Best buy is through costco / BJ's / Sam's Club could snag synthetic for about $4-$5/qt).

Dr_Snooz
06-25-2015, 09:14 PM
Has anyone actually had any trouble from not having enough zinc, or is it only a theoretical possibility? I've never heard of it, but I'm not omniscient. I'd be curious to know what's actually happened in the real world.

gp02a0083
06-26-2015, 11:01 AM
its a well known issue with my Oldsmobile friends, lifter areas are mostly affected on older flat tappet systems. Newer roller cams don't have as much of an issue but still can benefit. Due to EPA regulation changes in the early 2000's it was required that the zinc and phosphorous levels were reduced in favor of cleaner emissions and less of said compounds that can foul/poison the catalytic converters. Our engines thankfully do not have that kind of valve train, however our rockers ride on our cam's directly. It's still a metal - metal contact, take it which ever way you want to, personally ill stick to an oil with preferred metallurgy content.

Dr_Snooz
06-27-2015, 08:04 PM
Are they actually wrecking cams and valves or just having to replace a few more things during engine rebuilds?

Oldblueaccord
06-27-2015, 08:24 PM
My accord has some cam wear on the lobes. I don't think its excessive.

http://imageshack.com/a/img538/2088/zn93Ee.jpg

http://imageshack.com/a/img673/3526/M5iatX.jpg

All my other cars pretty much ok.

My 77 Chrysler with a 318 just runs.

I pulled the distributor on my 440 a few weeks ago to change out the pick up coil and the cam looked ok from what little i could see. Its the only one that has an aftermarket performance cam.

My IH 345 is ticking pretty good but it was when I bought it and they are known for it. I might dive into it but im not very motivated. Good chance there is a bent pushrod or 2 on there.