ZDDP in used cars

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I understand that a newly rebuilt engine needs added zinc on a rebuild. But how about cars from the high zinc era that are still on the road? Just used cars, or classic/muscle era cars that have never been rebuilt or rebuilt many years ago? Would they still need the added zinc? It seems to me as one poster said a while back, if low zinc levels were such an issue with SM and SN oils then wouldn't the TV Trail Lawyers be all over this? Call 1-800-LowZinc. Any thoughts?
 
Unless it has a particularly aggressive cam (pretty small percentage of the flat-tappet cams out there) my observations/experience says it's not a big deal.
 
Most of them out there (post 73) had such wussy broomstick camshafts, that other than break in, it is hardly a necessity.

I still prefer to err on the side of caution and run a good HDEO at a minimum.
 
Gm had huge camshaft failures in the late 60's and into the late 70's. But it was bad parts,not oil related.

Some engines had more problems than others. The low perf 350 Chevy for example ate cams. But the hipo ones didn't. Different cam suppliers.

Any hipo engine around today would definatly need zddp. The old 375hp/396, 340 Mopar etc.
 
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ZDDP (and its components) is an extreme pressure additive. The only place in an engine that requires such an additive is the interface between a camshaft lobe and a flat tappet lifter or non-roller cam follower.

If you engine has roller lifters or roller cam followers, you don't need any such additive. Not during break-in, not during normal operation. You just don't need it.

Looking back to vehicles that were from the "high zinc" timeframe:

First, most of them are dead, gone, and forgotten. It doesn't matter what oil they use when they're in the junkyard.

Second, automakers have been using roller lifters and roller followers since the mid-80s. Zinc additives haven't been an issue for most cars for a long time. The notable exception is the Jeep 4.0L that went well into the 2000s using flat tappet lifters.

Third, most engines don't *need* much extreme pressure additive and modern oils still have some. In most cases, they still have enough to keep engines from wiping cam lobes. See the Jeep example above. There are millions of Jeep TJ, ZJ, and XJ driving around with a flat tappet 4.0L and SM oil that aren't lunching cams and lifters.

The notable exception to all this are performance cars. An aggressive camshaft and high valve spring pressure is when the ZDDP is needed. From that point, if you have a muscle car from that era, it's one of those things that you just know. Like non-hardened valve seat wear after lead was taken out of gas, you just learn what additive is needed to keep the car happy.
 
Originally Posted By: Chris142
Gm had huge camshaft failures in the late 60's and into the late 70's. But it was bad parts,not oil related.



They also had problems in the 80s with the cam in the 305 engine too. Even though it was a design flaw, I wonder if perhaps the lesser quality conventional oils used at the time helped to speed up the problem? So if someone had that same engine today but ran a modern synthetic in it, would it still have cam problems?
 
Originally Posted By: Kamele0N
Just use HDEO oils...&non emission ones...

They still have plenty of "old" juice

Yep, and for a rebuilt engine I'd take it easy for the first 3000 miles.
 
Originally Posted By: MrHorspwer
ZDDP (and its components) is an extreme pressure additive. The only place in an engine that requires such an additive is the interface between a camshaft lobe and a flat tappet lifter or non-roller cam follower.

If you engine has roller lifters or roller cam followers, you don't need any such additive. Not during break-in, not during normal operation. You just don't need it.

Looking back to vehicles that were from the "high zinc" timeframe:

First, most of them are dead, gone, and forgotten. It doesn't matter what oil they use when they're in the junkyard.

Second, automakers have been using roller lifters and roller followers since the mid-80s. Zinc additives haven't been an issue for most cars for a long time. The notable exception is the Jeep 4.0L that went well into the 2000s using flat tappet lifters.

Third, most engines don't *need* much extreme pressure additive and modern oils still have some. In most cases, they still have enough to keep engines from wiping cam lobes. See the Jeep example above. There are millions of Jeep TJ, ZJ, and XJ driving around with a flat tappet 4.0L and SM oil that aren't lunching cams and lifters.

The notable exception to all this are performance cars. An aggressive camshaft and high valve spring pressure is when the ZDDP is needed. From that point, if you have a muscle car from that era, it's one of those things that you just know. Like non-hardened valve seat wear after lead was taken out of gas, you just learn what additive is needed to keep the car happy.


Let's see, flat-tappet engines used at least 5 years past "the mid 80's" - at least 1994, to be exact:
Jeep 4.0
Jeep 2.5
Chevy small block Gen 1
Chevy Big Block gen IV
Ford 300-6
Ford 460

I'm sure there are at least a couple more, but none of those were particularly rare engines.
 
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Originally Posted By: Patman
Originally Posted By: Chris142
Gm had huge camshaft failures in the late 60's and into the late 70's. But it was bad parts,not oil related.



They also had problems in the 80s with the cam in the 305 engine too. Even though it was a design flaw, I wonder if perhaps the lesser quality conventional oils used at the time helped to speed up the problem? So if someone had that same engine today but ran a modern synthetic in it, would it still have cam problems?
no oil will prevent wear if the part isn't made correctly.
 
Originally Posted By: Mr Nice
Originally Posted By: Kamele0N
Just use HDEO oils...&non emission ones...

They still have plenty of "old" juice

Yep, and for a rebuilt engine I'd take it easy for the first 3000 miles.


I wouldn't. All USA V8 engines used sling oil off the crank to lube the cam lobes. You need at least 2,000 RPM to make sure you have enough sling oil. Spin that motor to oil it. You can back off after it's well broken in
laugh.gif
 
Aren't there lots of other areas in any engine that see high psi loads besides flat tappets? What about pushrods against rocker arms? (Way less contact area and very high PSI). What about a rocker arm against a valve stem? What about a wrist pin bushing? What about a rocker arm fulcrum? Don't these areas need ZDDP too? Seems like if low ZDDP was an issue, there would be lots of other engine parts failing and not just flat tappet cams.

Toyota to this day still makes bucket and shim OHC engines, don't they? Buckets and shims are still "flat tappets" when it comes to cam lobe loading. There isn't a more trouble free setup than an OHC Toyota with buckets / shims. They seem to do just fine on the cheapest store brand oil people can find.
 
I just bought 2 comp cams to install in BBC rebuilds. Comp told me if I didn't use high zddp breakin oil, it would ruin the cams/lifters, and there would be no warranty coverage. The cams that came out were significantly worn, exhaust down around 10 thou. We used to use Rotella in them, but since Rotella has decreased the additive package, I will be using Amsoil Z-Rod oil after breakin. By the early '90s EPA regs prompted all the major engine manufacturers to use roller cams, but they along with the lifters are pretty expensive unless high performance is desired. I'm building a couple torquers, never to see above 4500 rpm. So fairly light springs will keep the wear down at least that is the plan.
 
I'm curious what the psi load is on other parts of an engine besides a flat tappet riding on a cam lobe.

It seems like lots of other engine parts with high loads would be failing even in current production engines if modern low zddp oils were really that lame at EP protection.

What's the psi load on a wrist pin bushing on a twin turbo Ford 2.7 ecoboost making 365 hp and 375 lb ft.?

Or a wrist pin in a supercharged ZO6 Corvette making 650 hp?
 
Originally Posted By: Scdevon
Aren't there lots of other areas in any engine that see high psi loads besides flat tappets? What about pushrods against rocker arms? (Way less contact area and very high PSI). What about a rocker arm against a valve stem? What about a wrist pin bushing? What about a rocker arm fulcrum? Don't these areas need ZDDP too? Seems like if low ZDDP was an issue, there would be lots of other engine parts failing and not just flat tappet cams.

Toyota to this day still makes bucket and shim OHC engines, don't they? Buckets and shims are still "flat tappets" when it comes to cam lobe loading. There isn't a more trouble free setup than an OHC Toyota with buckets / shims. They seem to do just fine on the cheapest store brand oil people can find.


Same with Nissan and my Saab B235 has cam on bucket lifters, no rollers in sight

Just a couple of clarifications:
-American Metallurgy for cams has traditionally/historically been poorer than Japan or Europe (just admit it, you know it's true)
-Most Japanese Engines have oil holes in the cam lobes to directly oil the cam and lifter interface surface (it's just a better system.)
-Due to the design of a DOHC cam on bucket design, the lifter is not required or expected to be rotated by the cam, this is only a function of push-rod designs. Thus like a V8-roller-push-rod, the cam / lifter interface is at a perfect 90° = less wear.
-Modest displacement Japanese and European engines with 4V-cylinder heads typically run much lower lift numbers 8-9mm in many cases. 2V-pushrod large displacement American lumps are almost always +10mm, if not +12.5mm.
-The mass of the pushrod assembly + positive rocker ratio's requires significantly stiffer valve springs to ensure stability at high RPM. This then puts a much higher stress on the lobe / lifter interface vs DOHC designs. It's also why nascar specify a maximum crank to cam spacing for their race engines. as the shorter you can make your pushrods, the less mass you have reciprocating. take a look at the amazing Ilmor pushrod indy V8 from the early 90's to see this taken to the extreme.)
-Thus because of the extra valve area (2 vs 1 intake) = lower lift required to flow + lower mass: DOHC can run softer springs and still perform easily past 7000RPM.

My CA18DET race engine (circuit, not drag so it's built to survive) makes peak power at 8,500RPM swallowing 25PSi of boost; the cam is a 270° 8.8mm. We use a stiffer than stock, but still single valve spring. No issues. Run Helix Ultra 5W40.

2 modest sized valves opening a modest amount is always preferable to 1 large valve having to open a large amount
smile.gif


regards
Jordan
 
Originally Posted By: Scdevon
Aren't there lots of other areas in any engine that see high psi loads besides flat tappets? What about pushrods against rocker arms? (Way less contact area and very high PSI). What about a rocker arm against a valve stem? What about a wrist pin bushing? What about a rocker arm fulcrum? Don't these areas need ZDDP too? Seems like if low ZDDP was an issue, there would be lots of other engine parts failing and not just flat tappet cams.

Toyota to this day still makes bucket and shim OHC engines, don't they? Buckets and shims are still "flat tappets" when it comes to cam lobe loading. There isn't a more trouble free setup than an OHC Toyota with buckets / shims. They seem to do just fine on the cheapest store brand oil people can find.


Yeah, but push-rods are direct lubed by the lifter pumping up through the push-rod on many engines. That same squirt comes out the top hole and lubes the fulcrum. The valve stem tip is splash oiled, usually, but does benefit from some drool off the fulcrum ...

It's almost always the face hardness of the lifter and the lobe prep/metallurgy of the cam core that causes issues. Premium oils are just band-aids ... Then there is the whole issue of off-center lifter bores and core shifted cam journal bores, etc.

USA V8's are cheaply produced in bottom $$ configurations. Assemblies of low bid parts on aging tooling without a lot of QA/QC checking ... Euro cars, not so much - well maybe eastern european ones ...

If your used USA V8 car has survived to say 75,000 miles and is not clacking and running rough - it's prolly OK on most modern oils. IF it's running oddly, or clicking and clacking, you know you need motor work, or a replacement.

Junk-yard engines with over 90K with decent compression are likely solid out to 150,000+ miles easy. The whole cam thing was mostly GM designs. Not many SBF's died from cam failures. Ditto Chrysler motors I have worked on. GM could really shoot themselves in the foot trying to save a nickle ...
 
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Originally Posted By: BrocLuno


Yeah, but push-rods are direct lubed by the lifter pumping up through the push-rod on many engines. That same squirt comes out the top hole and lubes the fulcrum. The valve stem tip is splash oiled, usually, but does benefit from some drool off the fulcrum ...


These parts all get plenty of oil. I wasn't saying that. I was pointing out that there are many areas of even a roller tappet engine that see high psi loads that seem to do just fine on "low zddp" oils. I doubt the psi load on each needle bearing on a roller lifter is less than the "ramp up" load of a flat tappet against a cam lobe. There is really only one tiny needle bearing at any given time supporting almost 100% of the tappet load even on a roller lifter. I'm talking about engines produced today.

Quantity of oil on these parts are almost never a problem. Oil formulation and EP additives is what the debate is about.
 
All those millions of Jeeps still on the road with the 4.0 flat tappet 6 known to last over 250,000 miles...Do you think most owners care about the oil in the crankcase? Chevy truck 305-350's never has roller lifters until 1996...Not that SBC's are know for long cam life but who knows what oil is in them and it doesn't seem to be a problem
In new engine yes, with a hotter cam yes......Otherwise it probably makes little difference

On the OHC stuff? I have no experience but it seems they do ok with any type oil...
 
To Mike Thompson: I just want to clarify: You had been using Rotella in these engines and the camshafts failed? I ask because all Rotella oils have had over 1000 ppm of zinc and phosphorous until recently. Now the SN rated T6 does not, but all of the others are over 1000, I think 1200 ppm. Did Comp Cams give you a ppm minimum level that they need for their camshafts? That would be good to know. Thanks
 
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