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Considering that the EPA has gradually phased out the amount of ZDDP in available on-the-shelf oils it's probably worthwhile to make mention of 'High Zinc' alternatives that are readily available for performance cam users... Lots of people don't even have a clue that the 'better technology' of the newest oils has absolutely no value when it comes to preserving the life of your camshaft, lifters, and rings but is engineered to preserve the life of your catalytic converter (and which one would you really rather replace every 2 years)
I have been using Mobil 1 SJ/SN or CJ4 /CI4 (High Mileage and Turbo-Diesel) for a good while now as these contain roughly 1100ppm and can be found most anywhere.
Recently I ran across Brad Penn and Cen-Pe-Co oils which contain between 1500 and 1800 ppm depending on the specific grade you choose. Both are formulated in the U.S. and derived from paraffin based Pennsylvania crude. These are formulated to be run as-is with no additional additive package specifically for both hydraulic and mechanical flat-tappet cam engines.
this is going to start another oil flaming contest, rotella has been proven in general as have the full synthetic oils. idk what your talking about with the camshafts but ive taken down extremely high mileage motors and if theyve been running modern full syn oils and had most of the mileage stacked on in the last decade then if there is significant wear it will be everywhere not just the cam and lifters or rings, itll be on the cyl walls the main and rod bearings the crank and rod ends, cam bearings, sprockets, timing chain and cover.......all of it. the fact is the newer synthetic oils protect better for longer under normal conditions, adding performace thru modification hasnt changed either, add hp and you add wear.
idk what your talking about with the camshafts but ive taken down extremely high mileage motors and if theyve been running modern full syn oils and had most of the mileage stacked on in the last decade then if there is significant wear it will be everywhere not just the cam and lifters or rings, itll be on the cyl walls the main and rod bearings the crank and rod ends, cam bearings, sprockets, timing chain and cover.......all of it. the fact is the newer synthetic oils protect better for longer under normal conditions, adding performace thru modification hasnt changed either, add hp and you add wear.
I posted this merely to bring to light some specific facts regarding ZINC content...but, since you raise the point let me add the following:
You were not even born when the EPA began to require the phase out of lead in gasoline. Therefore, you might appreciate the importance of this example as it relates to oil. When lead content began to decline and 'Low-Lead' and eventually 'No-Lead' arrived on the scene, the automotive industry had to deal with valve failure occurring much more frequently. People got really aggravated that cylinder heads needed more frequent reworks because the lead content was no longer adequate enough to properly lubricate the valve seat and head causing premature erosion. The result was changes in the metallurgy of valves and seats to be able to last on unleaded gas (very similar in principle to running specific parts on alcohol fuels).
Fast forward to today, and we have a similar problem with high stress metal parts and the absence of zinc because of the EPA mandated changes again. The issue is not general internal wear, but camshaft and lifter specific wear.
The industry has made internal changes in construction (roller cams for instance) that can survive on 'Low Zinc' oils, both conventional and synthetic...and you are correct in that a synthetic is an all-around better 'oil' to use. However, vehicles (motors) built within the last 15 or so years have been changed to be accomodating of 'Low Zinc' oil formulations. So it's not a surprise that you would find lots of motors that look pretty good on tear-down.
The issue happens because of the higher valve spring pressure that comes with aftermarket, replacement camshafts and the lobe profiles. Low-Lift stock and roller cam applications don't have this issue. Older motors with aggressive flat-tappet cams that are being run today, or even newly rebuilt stock motors (like AMC 258 i6 / 4.2l /4.0) with a stock flat-tappet cam are prone to premature lifter/lobe failure if there isn't enough zinc in the operating oil, even if they were broken in with a 'Hi-Zinc' break-in oil to start with.
This 'wear' btw is not noticeable (usually) on other parts as you tried to suggest because they are not under the same loading pressure...and the reduced zinc content is good enough for gears, sprockets,and bearings...just not for camshafts.
Now since there aren't roller cam offerings (far as I know) for the Jeep AMC 258 i6 / 4.2l /4.0, it becomes important to understand exactly why a synthetic oil MAY FAIL your motor, even if everything else works right, and might look fine on a tear-down. Your AMC 150 ,000 mile cam suddenly becomes a 75,000 mile cam or less. Of course, if the 'wrong' oil caused failure within a few hours of starting the motor...it might make more sense to you upon inspection. But a lot of Jeepers are rebuilding their motors 'old school'...and mistakenly thinking that the 'newest' oils are clearly the best for their motor...only to find a bum lobe or malfunctioning lifter at 20,000 miles or less, and blaming it on a 'bad lifter' or 'crappy cam grind', because their Toyota or Prius got 100,000 on Rotella, and I use that in my Jeep. So it can't be the oil, right
That said, I am NOT recommending a specific oil because I don't have the lab facilities to do the testing. But I do recommend that you educate yourselves about the abundant literature on catastrophic cam and lifter failure caused by 'Low Zinc' formulation oil. And while your at it...get the actual numbers for zinc content in your oil of choice BEFORE you start swearing that it's God's gift to automobiles. That idle problem you can't tune out just may be an early sign of cam failure because you didn't know any better.
roller lifters are out there, anyone wanting reliability and doing a build for longevity should be putting roller lifters and rockers in the motor regardless, i did it to a 88 5.0 during the rebuild and it barely added to the cost, it was on a shoestring budget and definitely paid for itself in gas mileage after the rebuild. not putting roller timing gear in a motor now is like putting soft valve seats in a head, why, unless you've got ppl inspecting you for a car show and they want to see the lifters for some reason why wouldnt you move into the modern age, its not just environmental, it reduces drive train friction losses.
roller lifters are out there, anyone wanting reliability and doing a build for longevity should be putting roller lifters and rockers in the motor regardless, i did it to a 88 5.0 during the rebuild and it barely added to the cost, it was on a shoestring budget and definitely paid for itself in gas mileage after the rebuild. not putting roller timing gear in a motor now is like putting soft valve seats in a head, why, unless you've got ppl inspecting you for a car show and they want to see the lifters for some reason why wouldnt you move into the modern age, its not just environmental, it reduces drive train friction losses.
If you have a source for a roller cam for a 4.0, SPEAK -UP...I have roller rockers, and I know that MOPAR small-block lifters (.904 dia.) CAN be adapted to the AMC 258 i6 / 4.2l (with block machining)...but I haven't found any drop-in solutions...
Serious gear there...way too much for a DD I would think though...I could get more serious about gearing, but with the 4.10 I have now...I only see 2000 rpm when I upshift...and in 5th I'm already at 62 mph with 33" tires...that roller wouldn't even be breathing...But it is awesome, thanks!
I just had the engine rebuilt for my '78, and the "high zinc" oil was specifically mentioned by the rebuilders, to prevent premature engine wear. I haven't got to the point of running the new engine yet, but really would like to know a good brand to try to find. Do most major auto parts stores carry something functional?
is for MOBIL, but gives a good accounting of the API/ACEA specs...what it doesn't do, is tell you anything about other oils.
The High Mileage AND Turbo/Diesel oils from other manufacturers probably carry good amounts of ZINC (Valvoline ZR-1 comes to mind as well), but the API rating by itself,is misleading.
You need to research the zinc content of the oil you can find at the store, or order it.
I recently found the specs for Brad Penn and Cen-Pe-Co oils and these are the highest zinc content oils I have found so far. Joe Gibbs is also a recommended oil from several builders I know.
Basically, run your motor on a break-in specific oil for 500 - 1000 miles before you go to your regular store shelf oil. But, if you have a flat-tappet cam I would not run any oil with less than 800 - 1000 ppm of zinc after it's broken in. And if you have a catalytic converter on your motor, start shopping soon for it's replacement because in about 1 1/2 years it will start failing inspections. Or, do like me...live in a state with no inspections, remove the cat, install a performance cam, and keep the highest zinc content oil in it you can find.
(please save the 'green, eco-friendly lecture, and don't start with the climate warming thing...I more than offset my Jeeps' carbon footprint in other ways...).
I keep the "non-catalyst" sticker on my dash with pride! I'll stop by NAPA on the way to work in a few days to see what they have/recommend. I know someone who races Modifieds (dirt trackers) and I'll see what he says. Thanks for the advice!
You will find versions of this on every cam product and engine builder site you go to...Pay particular attention to the description about synthetics...NO ZINC...(also note the phrase '...ON ROAD oils...'). It's your motor, run it the way you want...
And I might add that this warning came with ROLLER ROCKERS
They (rebuilders) advised me to use a good zinc-enhanced break-in oil, and also to use it in the engine all the time, not just at first. Thus my original question about some recommendations. I don't have an issue with searching out and using what's recommended, especially for the money paid to rebuild the engine.
This is what I plan to do. Either use a good zinc-enhanced oil, or a suitable additive.