More ZDDP better for shorter intervals?

[FastSUV]

I seem to have read somewhere that approaching levels of ZDDP above SM rated oils does no good on a flat tappet stock motor except to allow the oil to go LONGER OCI before it quits offering the anti-wear protection? So if this is true & you so not push the OCI then is the 6-800ppm (or whatever SM oils tend to be) plenty for those cam lobes?

 

[Turk]

The only longer OCI I do is with PP & Amsoil.

 

[lipadj46]

Yes if you stick with 3k/3 month OCI you should be fine IMO. I have a flat tappet V8 on my discovery and I did not start using synthetics with high ZDDP until 75,000 miles. When I did my head gaskets at 100,000 my camshaft and tappets looked normal.

 

[FastSUV]

Originally Posted By: lipadj46
Yes if you stick with 3k/3 month OCI you should be fine IMO. I have a flat tappet V8 on my discovery and I did not start using synthetics with high ZDDP until 75,000 miles. When I did my head gaskets at 100,000 my camshaft and tappets looked normal.


what about 5k??? Too long on stock flat-tappet 4.0L Jeep & plain-jane SM dino? I was thinking most dino's additive pks are good to 5k except for severe service but is that still the case on flat tappet?

 

[lipadj46]

I'm not sure. I can tell you I did not change my oil religiously at 3k and got whatever oil the oil change place gave me (this was pre DIY). I'm sure I went to 5k miles more than a few times in the 75,000 miles of Dino. I can also say that my engine was not the cleanest when I cracked it open. Lots of varnish some sludge. Not terrible but not great. I'm hoping the HDEO detergents over the next year will clean things out on the bottom end (I cleaned the top end well). I need to replace the front engine cover gasket in the spring so the oil pan will come off then for a look-see.

 

[JohnBrowning]

Tell that to all the flat tappet or lifter people that have wiped oput cam's and lifters left and rioght lately. The only thing saving most is that most engines today are rollerized and most all of them use very mild cam profiles. So by combining weak cam profiles with soft springs and rollerized rockers and lifters etc......You have reduced the laod that the parts see so less AW and EP additives needed. The problem is for all those car built before rollorized lifters and rockers became OEM normal!THose that are not useing rollers still have gimb cam profiles and weak cam springs and are useing more expensive materials and heat treats to over come the lack of good additive package.

IF ZDDP is a bunch of hooey then how come most diesel oils still use plenty of it?

 

[Gary Allan]

Quote:
IF ZDDP is a bunch of hooey then how come most diesel oils still use plenty of it?


Because you don't buy one out of common habit. No one buys one with the idea that they're going to have service that's varied from senseless mild to 24/7 capability.

Ask Doug if he drove one of his tractors as a daily driver with just him as a commuter for
Viscosity is in the same boat. I could say "well, if visc truly lowers wear, why aren't the OTR diesels using 70 weight ..the preferred oil in Oz? It surely isn't for CAFE.

I still think it's a TWA (time weighted average) thing. "How many lbs of zinc phos do you put through the engine on a per mile basis. Your requirements are your requirements, but what makes you think you're short changing them with SM?

 

[lipadj46]

I'm not sure who called it a bunch of hooey. I'm just saying before I knew better I used regular conventional oil in my flat tappet engine and did not see any obvious signs of premature wear on my camshaft or tappets at 100,000 miles. That being said my rover engine is an old buick designed engine and not exactly a performance engine. Regardless I use Rotella 5w-40 now or Mobil 1 15W-50.

 

[Gary Allan]

Not an unsound policy.

 

[Chris142]

Originally Posted By: JohnBrowning


IF ZDDP is a bunch of hooey then how come most diesel oils still use plenty of it?
And most if not all diesels have been rollerized for many years. The cummins in my 62 pete has roller cam followers.

 

[BuickGN]

I've posted many times about the experiences in the GN world using SM oils in stock engines but I feel like I'm wasting my breath. Short version, yes, lower ZDDP does make a difference in bone stock broken in flat tappet engines.

 

[FastSUV]

Originally Posted By: BuickGN
I've posted many times about the experiences in the GN world using SM oils in stock engines but I feel like I'm wasting my breath. Short version, yes, lower ZDDP does make a difference in bone stock broken in flat tappet engines.


so what is the remedy?

 

[lipadj46]

Use an oil with high ZDDP concentrations. There are many out there even at walmart. There are also the zddp additives just be careful don't go overboard.

 

[FastSUV]

Originally Posted By: lipadj46
Use an oil with high ZDDP concentrations. There are many out there even at walmart. There are also the zddp additives just be careful don't go overboard.


well that is why I was asking about STP in another thread...to boost the oil's ZDDP levels

 

[lipadj46]

Sure people do it especially with old flat tappet engines. It's not really for the modern engine though.

 

[FastSUV]

Originally Posted By: lipadj46
Sure people do it especially with old flat tappet engines. It's not really for the modern engine though.


but don't you & have have flat-tappet? what makes out flat-tappets so different than a 1979 chevy truck?

 

[BuickGN]

Originally Posted By: FastSUV
Originally Posted By: BuickGN
I've posted many times about the experiences in the GN world using SM oils in stock engines but I feel like I'm wasting my breath. Short version, yes, lower ZDDP does make a difference in bone stock broken in flat tappet engines.


so what is the remedy?


To use an oil with more ZDDP. Some failed, some did not but there was a much higher than usual cam failure rate with the newer oils.

Keep in mind, usually when the cam goes it takes the rest of the engine with it.