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Stock XJ Cherokee Tech. All XJ Non-modified/stock questions go hereXJ (84-01)
All OEM related XJ specific tech. Examples, no start, general maintenance or anything that's stock.
You guys are on a good one! Im going to throw in some facts about zinc, zddp, Zinc Dialkyl Dithiophosphate, or whatever you want to call it. Its a synthetic material designed to do one thing, bond to metal and create a hardened barrier. Why is that so important when talking about flat tappet lifters? Well first off, you have a soft cast lifter pushing down on a hardened cam. Two dissimilar metals. You dont have oil psi between the lifter and the cam to help the direct metal on metal contact. So how do you slow down the metal on metal wear? Zinc Dialkyl Dithiophosphate. It forms a metal like layer on the cam and lifters helping not have direct metal on metal contact. It really is science down to the molecular level. All im saying is that zddp is an additive designed to do one thing and one thing only. I would rather have too much then not enough.
Rob's going to come back after his trip and say, "WTF did I get myself into here?"
Originally Posted by 5-Speed
You guys are on a good one! Im going to throw in some facts about zinc, zddp, Zinc Dialkyl Dithiophosphate, or whatever you want to call it. Its a synthetic material designed to do one thing, bond to metal and create a hardened barrier. Why is that so important when talking about flat tappet lifters? Well first off, you have a soft cast lifter pushing down on a hardened cam. Two dissimilar metals. You dont have oil psi between the lifter and the cam to help the direct metal on metal contact. So how do you slow down the metal on metal wear? Zinc Dialkyl Dithiophosphate. It forms a metal like layer on the cam and lifters helping not have direct metal on metal contact. It really is science down to the molecular level. All im saying is that zddp is an additive designed to do one thing and one thing only. I would rather have too much then not enough.
That's all entirely true.
But none of that addresses the fundamental question: Does the stock 4.0L need more than 800 PPM of ZDDP?
There's no evidence that it does. The experts say it doesn't. GM even issued a technical paper that said stock flat tappet motors don't need it. Part of the SAE certification process involved ensuring the new oil was backward compatible by running it in flat tappet engines and observing the results. The results showed no greater wear with the new oil.
Nobody has been able to demonstrate a statistical increase in camshaft failures in stock 4.0L motors. Nobody has run a sample of stock 4.0s with and without extra ZDDP and reported any evidence of a difference. There. Is. No. Scientific. Evidence. Period.
The only people insisting you need more zinc are these religious fanatics who read some nonsense on the internet, became believers and then use failed break-ins and aggressive aftermarket cams with wiped lobes as "proof" of absolutely nothing. Especially the Cult of Rotella. Those people are worse than Scientologists.
Rob's going to come back after his trip and say, "WTF did I get myself into here?"
That's all entirely true.
But none of that addresses the fundamental question: Does the stock 4.0L need more than 800 PPM of ZDDP?
There's no evidence that it does. The experts say it doesn't. GM even issued a technical paper that said stock flat tappet motors don't need it. Part of the SAE certification process involved ensuring the new oil was backward compatible by running it in flat tappet engines and observing the results. The results showed no greater wear with the new oil.
Nobody has been able to demonstrate a statistical increase in camshaft failures in stock 4.0L motors. Nobody has run a sample of stock 4.0s with and without extra ZDDP and reported any evidence of a difference. There. Is. No. Scientific. Evidence. Period.
The only people insisting you need more zinc are these religious fanatics who read some nonsense on the internet, became believers and then use failed break-ins and aggressive aftermarket cams with wiped lobes as "proof" of absolutely nothing. Especially the Cult of Rotella. Those people are worse than Scientologists.
Edit - my post above this had nothing to do with what I think our Jeeps need. Just some fun facts about zddp and to help others understand what it actually is and does.
Im not going to answer the question to does it need more then 800 ppm. I didnt design the engine. Whatever the ppm in the oil that was in my Jeep when it left the factory is what it needs. Chrysler designed it and put what they proved would work in it.
As for breaking in a cam, techincally you can use standard oil with no "high zinc" formula. That is ONLY if you use the correct assembly lube and the correct amount. Why? Cause the assembly lube carries the extra zddp you need and will mix in with the oil.
As far as the cult of Rotella, yep I am with them, for now. Did I choose it cause of the high zddp content? Partially yes. But the bigger factor was its cleaning agents. Like most Jeeps, mine had lack of maintenance by the po. So with Rotella, I am cleaning it out one oil change at a time. Once I feel its clean, I am switching over to Lucas. Their oil is blue so it must be good!
Im not going to answer the question to does it need more then 800 ppm. I didnt design the engine. Whatever the ppm in the oil that was in my Jeep when it left the factory is what it needs. Chrysler designed it and put what they proved would work in it.
Chrysler continued to specify 10W-30 passenger car oil through the 4.0L's entire run. That run ended in 2006, AFTER the reduction of zinc to 800 ppm. There wasn't a big run of camshaft failures in those later year 4.0L motors, so they must have gotten the spec right.
Therefore, even if you just go by what the manufacturer specified, regular passenger car oil should be just fine.
Going back to a point in your earlier post:
Originally Posted by 5-Speed
I would rather have too much then not enough.
Unless you're running catalytic converters or need them to pass inspection. Phosphorous eats them. It's bad enough on a distributor XJ, but if you have a CA 2000 or 2001, those front cats can get expensive.
It's funny watching the panicked posts on FB every now and then when someone fails inspection for "catalyst inefficiency," and it turns out they have been running Rotella because some religious nut told them, "Moar Zinc! It's what a motor craves!"
has it occurred to anyone that the 4.0 in question isn’t the only flat tappet camshaft motor still around? my old ford is a flat tappet engine. it’s 30 years old still on the original engine, no rebuild or replaced hard parts. it has 140k on it. if regular oil was that bad it would have lunched the valvetrain by now.
coffeecommando: do you have any 4.0 success stories? it’s difficult to heed advice from someone with several failures and nothing positive. just saying.
has it occurred to anyone that the 4.0 in question isn’t the only flat tappet camshaft motor still around? my old ford is a flat tappet engine. it’s 30 years old still on the original engine, no rebuild or replaced hard parts. it has 140k on it. if regular oil was that bad it would have lunched the valvetrain by now.
coffeecommando: do you have any 4.0 success stories? it’s difficult to heed advice from someone with several failures and nothing positive. just saying.
You don't learn anything from successes. You learn from failures, that's life 101. Most people think avoiding risk and playing it safe is how you learn. That's how you keep doing the same thing you've always done. You're on a race against time with decreased zinc levels in oil. You're at 140k. Mine was at 180K before it was rebuilt. Some oils will do better than others. Not every vehicle owner is using the same oils. Some will spend the $50-60 bucks on a full synthetic, every oil change. Zinc levels become less important in that instance.
I was just looking at some oil videos (learning is my idea of fun). Eric the car guy interviewed some engineers at Valvoline and they get into the details of what's going on with oils, even ZDDP. It's exactly like 5-Speed said.
Can I ask a question that may betray my inexperience, short attention span or both?
So without taking a side in this debate, do both the zinc and non-zinc folks agree that the full synthetic oil change, while pricey, is --- A --- recommended way to long and happy engine life?
Beyond that the only thing I can offer for this conversation is my personal experiences with successful engine longevity --
My Dad had a 94 XJ - bought new. He followed the manufacturer break-in and used only Mobil-1 Full Synthetic 5-30 and changed the oil every 5k without fail. His XJ on the day it went out of service had 400k original miles. The engine ran beautifully - his problem was severe rust.
I bought a 2000 TJ - brand new in 2000. I followed the manufacturer break-in. As annoying as it was to drive to work in my brand new vehicle going 10-15 miles under the speed limit on the highway for a couple weeks, I didn't mind. I used only Mobil-1 Full synthetic 5-30 or 10-30 and was *pretty* good about changing the oil on the proper schedule. On the day I turned in the plates it had (has) 305k miles on the engine. On that day, and unless it has deteriorated due to sitting for 3.5 years, the engine ran perfectly with no engine problem at all during the life of the vehicle (despite having the 0331 head and more than one overheating experience.)
Now what to credit the longevity of these 2 (I have to think must be considered) 4.0L "Success" stories? Was it a great engine design? Was it following the break-in instructions to the letter? Was it the Mobil-1 oil? Some combination of those or something else even?
I don't know. I can't think I'd spend top dollar on a vehicle only to directly ignore the operating instructions, not then, not now, not ever. The instructions are there because the manufacturer somehow determined that their product works best in that way. Good enough for me.
As Mobil-1 is available in 5 gal jugs at my local Wal-mart at about $22 - I'm just fine with paying about $33 for oil change supplies.
As automotive technology advances and my favorite vehicle is still the old manual I6, I've become sensitive to the fact that what is mainstream may have passed me by. That is the heart of the debate y'all are having, but it sounds like I'd be just fine since I'm using Full synthetic anyway... right?
I would only recommend synthetic to people doing extended oil change intervals. Today's conventional oils are excellent and will offer all the performance and protection you'll need for a 3-5K interval. Most off-the-shelf "synthetic" oils are made from highly refined petroleum base stocks anyway.
I'm not saying don't run synthetic. I'm just saying that I highly doubt you will get more life out of your engine running synthetic with normal oil change intervals.
In that video, and one of Eric The Car Guy's other videos, he talks about conventional vs synthetic. Synthetic is always better. Some people fear it because they put it in their old oil-leaky vehicle and it leaks worse. The reason is synthetic has better cleaning properties and the accumulated sludge around leaking areas gets cleaned out.
Had they been using synthetic from the get go they wouldn't have had accumulated byproducts building up in their oil to begin with.
Synthetic isn't meant to last longer, it's meant to be a better anti-wear oil. You're still supposed to change it at the same rate you do conventional oils. Some people just think because synthetic is "better" it can be ran longer, and that's not the case.
Synthetic isn't meant to last longer, it's meant to be a better anti-wear oil. You're still supposed to change it at the same rate you do conventional oils. Some people just think because synthetic is "better" it can be ran longer, and that's not the case.
Not always the case for sure. Many synthetics are formulated specifically for longer drain intervals though, especially those few that have true synthetic base stocks and aren't just formulated with highly refined petroleum base stocks. You must keep in mind that many products labelled synthetic in the U.S. are not actually synthetic at all, and many of them don't offer much advantage in performance and protection over products labelled as conventional oils.
As you have read, the dead worn lifter stopped the Jeep from doing Death Valley. Now home from the trip, great place, but would have been better in the Jeep in that we could have gone further, but the stock Ford Escape and raised 2wd VW Vanagon did better than expected on the off road trails, we could have gone further had we tried some road repairs with our shovels and planks, but it would have been very slow going. We met some really nice Jeep folks with Rubicons, and hope to meet up with them next year when our Jeep is up and running.
Now that we are back it is time to deal with the Jeeps motor.
1. I see a 4.0 liter motor repair book published by Workbench Series, and would like to know if this is a good book, is it worth buying?
link... https://www.walmart.com/ip/Jeep-4-0-Engines/35072061?wmlspartner=wlpa&selectedSellerId=0&adid= 22222222227023234831&wl0=&wl1=g&wl2=t&wl3=53103318 168&wl4=pla-75188935008&wl5=9032179&wl6=&wl7=&wl8=&wl9=pla&wl1 0=8175035&wl11=online&wl12=35072061&wl13=&veh=sem
2. now we need to decide on our options...
a).. New long block ( Recall we have a brand new cylinder head so if we can buy an engine without a head we can place our new head on it as a money saving option, this would probably be prefered I supoose, right?)
b).. Replace our cam with a new one, get 12 new lifters and put her back together with our existing new head, and hope the bottom end is ok. Note we had good oil pressure and compression prior to the lifter fail, oil pressure was still good after lifter fail. Of course we will examain the camshaft bearing surfaces when we pull the cam, and if found to be damaged, we will assume the cam bearing in the block are bad, and we will then need to rebuild or replace the long block.
c).. Rebuild our engine, although we really dont want to spend that much time, so this probably is not pur best option right now.
3).. Performance up grades? keeping in mind we must pass Californias strict pain the butt smog testing. Jeep is registered in an enhanced smog test location, so the full dyno smog test is required.
a) Performance cam? no matter which choice above we make, we NEED a new camshaft, any recommendations? stock, higher lift etc, but MUST be smoggable.
b) If we do a new engine, stock, big bore pistons, stroker, compression increase, etc..? Money is a concern so any upgrades cant be too much more money than the stock parts. Also money saved on the motor can then be maybe better spent on other upgrades, like limited slip, lockers, wench, or ?????? Of course wed like it all, strong long lasting motor, performance engine parts, better drivetrain for wheeling etc... But we cant have it all, so where best to spend the money? money saved on the motor can be spent on other things.
From our limited experience with Jeeps, we think our best option right now would be simply a new cam, (Assuming the existing camshaft bearing surfaces are not beat up when we pull it and inspect) The new camshaft maybe stock or a mild smoggable performance one that is compatible with the stock valve springs that we already have in our new head) This would be the most money saving and time option, then we can discuss other upgrades for wheeling, .
Please let us know what you think on this, recommendations and pros and cons with the parts, which brands, etc.... for the engine, and any recommended engine books, (We have the factory service manual).
Probably your best option as long as the new head isn't a 0331.
3).. Performance up grades?
a) Performance cam?
Not worth it, as it sits brand new it is (was) 190 hp in a 3,000 lb vehicle. You would need at least another 100 to make any noticeable difference and the drive train won't handle it.
Just get it running and be
Probably your best option as long as the new head isn't a 0331.
3).. Performance up grades?
a) Performance cam?
Not worth it, as it sits brand new it is (was) 190 hp in a 3,000 lb vehicle. You would need at least another 100 to make any noticeable difference and the drive train won't handle it.
Just get it running and be
New long block is going to be cheaper. You can put the other one away and build it on the side as a spare. That's the cheapest route and the best IMO.
Stay away from "performance" valve train components like springs and rods. Cam and lifters are the weak point. Performance means higher tension to reduce valve float at higher RPM's. That increases lifter and cam lobe wear and you don't want that unless you're tearing the engine apart every few thousand miles.
Comp cams' lifters sound like they are higher quality design than others. I'm going to order 1 extra and disassemble it and compare it to run of the mill lifters I have here on hand. I'll disassemble a factory, an EngineTech, Melling, and a Comp Cam. I want to know if there is any differences. ET is made in the USA along with CC, but Melling is made in Mexico. I would assume the OEM's are EngineTech, but they might be.. MOPAR? I don't know.
I'm in the middle of a rebuild and I haven't seen anyone else do it so it's time to find out what's going on in there since this is such a common problem. Maybe I'll get it uploaded to Bleepin Jeep. I saw him take apart different oil filters and that was very enlightening. I liked the STP XL over Mobil 1, Bosch and K&N. Other than that the higher end Wix would be the best competitor from watching other videos.
Update: I decided to put in a new cam, lifters, and cam thrust plate, and hope all will be well; parts are arriving this week. While I'm at it I will also be doing the rear main seal. I plan on using a brass brush and acetone to clean the lifter bores. I will use a cam paste and ZDDP oil additive. Maybe the work will be complete in a week or so.
Some pics of the lifter and cam
worn cam after replacing just the lifters. worn lifter. don't be a fool and just replace the lifters like I did
Premature wear, my old nemesis. Also, when you prime the oil the first time, leave the valve cover off and watch the oil come out of the tips of the push rods. You'll notice that two cylinders are going to have rods that aren't oiling because the lifters are in their up-right and locked positions keeping the valves open. Grab a breaker bar and turn the engine over until they're down and continue priming the oil. Make sure you've already set the valve lash and preload BEFORE you do this. You want the engine to pressurize the lifters to the appropriate hydraulic levels itself from what I have read. I've read and done the pre-pump version and because I did that it kept opening the valves, A LOT, while I was trying to set lash. The oil will prevent the lifter pistons from compressing since liquids don't compress and it would be filled up. Since I have a wiped cam lobe myself now, and pre-pumping is what I did last week, I won't be doing that again.
Definitely watch this video. I don't think I'll be using synthetics myself, and according to AMSoil you definitely don't want to use it during break in. The detergents in them clean the faces of the lobes and lifters of not only debris, but ZDDP. The detergents compete for space with ZDDP. I don't like the sound of that at all. Diesel oils also have lots of cleaning detergents. I think I'll take the time to do a proper motorflush (to clear out carbon debris that synthetics normally clean) at each oil change so I don't have to worry about long term lobe wear from loss of ZDDP lubrication. You also don't want to put any additives in your oil. Just oil, and ZDDP. The Lucas TB Zinc is rated at 31,000 PPM in the 16oz bottle. If you diffuse that into even normal oil it will bring it up to over 5,000 ppm, but with a break in oil it will be much higher. I'm not sure what break in oil is but it seems like it should be 3,000 ppm or higher ( I read that comp-cams won't refund for a cam unless they test the oil and find those levels in there, so I assume their oil is at least that much).
It's a good thing I ordered legit break in oil x2. When you do yours you want to get two filters and two sets of oil. After the first 20-30 minutes of cam break in (maybe someone could shed light on whether 20 or 30 would be better in our applications, I'm going with 20 because I read an article showing the increasing cam-lobe temperatures as time progressed during break in and temperatures are indicative of friction)...
Where was I, oh yeah. After the break in change the oil and oil filter (after all my searching I will be using Wix XP exclusively since they're locally available, but AMSoil and Royal Purpls filters are just as good if not better). I highly recommend you get some magnets as well. I've been investigating that on the iNet and they definitely catch metallic particles. I read that 70% of engine wear occurs from microns at the 15 and smaller levels. Oil filters only catch 25~ (and it doesn't tell you what percentage, only AMSoil catches 20 and tells you the percentage that I have found so far). Those magnets will catch all of the (metal) microns that come near. Don't forget to change the oil at 500 miles after break in. I'll be using Joe Gibbs or Brad Penn myself, I haven't decided which yet.
I've watched videos on both ceramic and neodymium magnets that were used in filters then disassembled. Both worked, but ND's magnetism start tapering off in strength once they hit 175 degrees fahrenheit. I don't know if the oil filter gets that warm. Can someone who has a temperature sensor gun confirm what their readings are before me and Rob put our cams in for the break in?
Ceramics are good for 310~. If I don't hear any results I'm going to play it safe and just use ceramics until I can test the heat on the oil filter. If it hits 175 then I'll either need to use ceramics only or those special ND's that have higher heat temperature ratings. Neodymiums have much stronger pull force lb for lb than ceramics.
As for assembly lube that you should use on the lifters and cam lobes, there are lots of options out there. I've heard a lot of flaming on Lucas products (which makes sense since they're in the synthetic business), so I'm going with Joe Gibbs' Driven Assembly Grease. The testing article I read with pictures on it rated it an 8/10. The article seems like it was in favor of (their own) product so there might be a conflict of interest, but I can't agree with spending $11 x4 or 5 on 17 gram packets of ZPaste assembly lube. I spent the money to have CompCams nitride my cam so I feel better about using Joe Gibbs. Joe Gibbs and Brad Penn are the oils I consistently see being recommended and used for break in and racing applications because of the zinc (race engines have high lift lobes that are even more prone to wear than our cams because they need much heavier duty valve springs to prevent valve float). If that's what they're using to keep their cams alive then that's what I'm going to use too. The hot rod community has decades of experience to know what they're talking about.
01-06-2018, 01:44 PM
