Staking 4.7l Valve Seats - JeepForum.com
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post #1 of 24 Old 05-27-2020, 04:31 PM Thread Starter
Jimmy2Ton
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Staking 4.7l Valve Seats

Credits: First, I want to thank ct27gt for reminding me of a the industry term 'staking' based on my description. A term that I probably have not heard in 25 or 30 years :P I had used this technique on spindles and such way back when, but it never occured to me for this application.

Second credit goes to a guys on boobtube videos. Staking the valve seats was not my own idea. Heres to hoping it works

Work: I disassembled the engine, and cleaned much of it up. On inspection I have a high degree of confidence my head gaskets were not leaking, rather the oil consumption is from the intake. To be determined. I will explain why I dont have time for that later...

Anyway, I had no problem with servicing this engine @ 160k as I found numerous things that needed to be addressed, and considering the potential to drop a valve seat, TO ME its a no-brainer. Pay now, or later... Many of the pistons had a thick 0.5-1.0mm heavy crust. oil, not carbon. I included a pic. Unfortunately the piston visable was not one of the worst..

To stake the valve seats, I used a chisel point from an air hammer kit, and a 12oz hammer. the work was pretty straight forward.

A Tip: I recommend anyone doing this is to put your punch at a 90 degree angle to the area you are going to punch first. strike it a single time, reset the punch in the divit, and do it once more. Now that you have nice divit, you can turn your punch toward the valve seat without the punch slipping an bouncing around.

Unfortunately, I wont know if this works or blows up for quite some time. Probably late summer or early fall.

A personal note: The day I took the engine apart I was very upset. My wife was very ill in the hospital with coronavirus, and fixing things is my coping response. The day after I had to meet with doctors and lawyers, then more doctors the following day. Thankfully, she has since recovered, and is at home.

Tomorrow I will have surgery on my shoulder, and it will be several months before I am allowed this kind of physical activity again. I did manage to get the heads mounted unfortunatly the bolts did not pass inspection, and will need to be replaced, so they are not torqued yet. Since I have a great deal of responsibilities I have been cramming 6 months of anything that requires 2 arms into a short time, which is why I have not finished inspecting/diagnosing everything. I rushed to get some of the more heavy work done... I wont be able to reply to question (if any) until next week at the earliest.

Sorry for droning on, and thanks for reading. I hope that someone finds this useful...

JT

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post #2 of 24 Old 05-27-2020, 04:43 PM
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Great write-up. A lot of people are convinced the 4.7 has a real design or defect problem with dropping valve seats. From what I understand, Chrysler/Mopar's official stance on the matter has never wavered - no overheat, no dropped seat. Whatever the truth is, I do know this - if you overheat it, that will increase the liklihood of dropped seat issues. A previous owner overheated one of my WJs and it partially dropped two seats - maybe three (I can't remember).

Unfortunately, I don't see staking as a viable defense against overheating since the aluminum heads are so prone to warpage anyway under such circumstances. With warpage, you get head gaskets that give up the ghost or don't ever seal properly again. I'm not saying staking isn't worth it. I'm just saying if you don't fully and always address underlying overheating issues, then staking in itself isn't really going to save you at the end of the day.

In my opinion, what killed so many 4.7 engines during its heyday was NOT some manufacturing or design defect around the valves. Instead, it was a coolant system that you cannot visually inspect properly under some circumstances when low on coolant. What the owner is led to believe is that the coolant overflow/reservoir will show a low coolant condition and the system can be topped off there as needed. In reality, if there's a leak, even a very small leak and particularly at the top of the system such as the top of the radiator, what you end up with is a coolant system that expels coolant as vapor or a drip and at least partially replenishes not from the tank as designed but rather from the hole in the system - e.g. - the atmosphere.

The tank never shows to be running low on coolant but in reality the coolant level gradually gets lower and lower. Unless you're watching the coolant gauge, you may not notice overheating situations where the vehicle may still run but at a high enough temperature to increase the liklihood of a valve seat drop. The effect can be cumulative over a period of time and a number of serious but non-critical overheating incidents. In reading many postings on the forum over the years, apparently WJ radiators love to spring leaks at or along their plastic ABS seams.

Notice - a Chevy LS from that era has a different coolant system design that runs the coolant through a *pressure* bottle where you can always visually inspect the actual coolant level. I used to think this was an arbitrary design difference. Now, I think GM clearly had it right and Chrysler did not.

Rage! Rage against the dying of the Jeep.

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post #3 of 24 Old 05-28-2020, 07:54 AM
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Great pics of this process. I have been wanting to see one of these heads with the staking done, to see just what the process involves. (I havent yet boobtubed it myself)


Glad your wife is doing better, and good luck to you with the shoulder surgery, hope it heals nicely.



I wait with baited breath for your version on the great oil consumption debate. Dont leave me hanging please, as I have my own issues here....

'00LMTD-4.7l,242hd,D30,D44A,3.73's,True-trac front,Spartan rear,4" short arm lift,JK'sW/32's
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post #4 of 24 Old 05-28-2020, 08:33 AM
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I really don't have an opinion on oil consumption! Since both of my 4.7s leak a little here and there I've never thought it worthwhile to try and figure out how much they're actually burning (if at all) or what the cause of it might be.

I've always understood that a small amount of oil consumption should be considered normal for any engine - some a little more than others.

For the 4.7 specifically, valve stem seals often get the blame and that sounds reasonable. I've also read something about the piston design or the stroke possibly being a problem for some reason but I don't recall if it had anything to do with oil consumption or more to do with pre-ignition.

Maybe very slight/minor head warping allows a little oil where it's not supposed to be. Maybe the single flippable head gasket for both sides somehow causes some minor sealing issues in some cases. Maybe the PCV system isn't really very good...Who knows?

I would love to hear the opinion of someone who actually designed or helped design the 4.7 all the years now after the fact. What would they change or do differently? Seeing what's different in subsequent designs or revisions might provide some clues. Differences with the last iteration of the 4.7 - the "corsair" or something like that might provide insight as well. I'm not certain but I believe the block was never redesigned.

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post #5 of 24 Old 05-28-2020, 09:02 AM
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Yeah, I agree that SOME oil consumption is normal, but mine appears to be on track to use 2+ quarts between oil changes(5000 miles).That is a little excessive in my book. I occasionally see a puff of blue smoke now and then as well, so I lean towards the valve stem seals. But I also want to really look over the PCV system as well, before I tear into the heads. Just waiting on things to slow down at work....


P.S. My Jeep does not leak any oil currently,so I know it is all getting consumed. I cant stand leaks...

'00LMTD-4.7l,242hd,D30,D44A,3.73's,True-trac front,Spartan rear,4" short arm lift,JK'sW/32's
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post #6 of 24 Old 05-28-2020, 09:34 AM
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4.7 is bullet proof IF it does not overheat and gets correct oil changes. Biggest contributing issue I've seen is not doing the coolant refill correctly during servicing and "burping" the system by taking out the bleed screw on the aluminum housing.
If the engine is subjected to continued hard-wide-open-throttle, the center thrust bearing will wear enough that the crank will walk and wear the rear main seal....that then drips...onto the exhaust, typically giving you the burning oil stink at traffic lights.
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post #7 of 24 Old 05-28-2020, 09:37 AM
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Wow. If it's using THAT much between changes but it's otherwise running good and you only have occasional smoke, surely you're leaking most of the loss???

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post #8 of 24 Old 05-29-2020, 08:10 AM
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NO leaks, I have a new shop and shop floor as of last year. Can't have anything dripping in there. I do NOT like leaks.



I have had my son following me around on the occasional trailride, and he tells me that every once in a while he sees a puff of blue smoke, but I've never seen it.


And it runs like a swiss watch right now(knock on wood)

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post #9 of 24 Old 05-29-2020, 08:49 AM
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Agree on the valve stem seals being the issue. At around 200K, they are known to begin leaking.
They can be replaced. Several threads on the swap are around.
I would just run it.

'04 Freedom Edition HO & '04 Overland HO (previous '00 Laredo 4.7)
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post #10 of 24 Old 05-29-2020, 10:07 AM
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A few years back my ho would burn about 1/2qt a day ( 5 to 800 miles a day with occasional blue smoke after idling on trails. I replaced the seals and i might burn a 1/4qt between oil changes.


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post #11 of 24 Old 05-29-2020, 03:06 PM
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I've got about 160K on this so far, but it sat for two years untouched before i drove it home, so i may have a little more trouble than most with these seals. I looked at my PCV valve today and it was dry as a bone in the vacuum hose, so no oil eating going on there...Gotta be the valve guide seals...


thats good news for me 97Mule. Hope mine turns out that good....Just not looking forward to the passenger rear cylinders..

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post #12 of 24 Old 05-29-2020, 03:55 PM
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I think if I had to do valve stem seals I might just punt and yank the whole engine out. I had a good valve spring compressor (the giant C clamp kind) and the heads on a bench and *still* had enough trouble getting all of them removed that I didn't enjoy it.

The angles of the valves and the recesses in the heads make it harder than it ought to be. Throw in the madness of getting to them with all the wires, hoses and tight clearance of the 4.7 engine bay and I would go insane wrastlin' with it.

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post #13 of 24 Old 05-29-2020, 08:24 PM Thread Starter
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I'm back!! couldnt belive it! they didnt have to reattach the tendon after all so my recovery is 1 week instead of 6!!


Thank you for the kind words Bigrigr


I didnt read all the comment yet, but as far as oil consumption this one was losing about 1qt/100 mi when I got it. Snugged up the pan & valve cover bolts, then about 1qt/500 mi.


At 160k most of the stem seals were a bit firm, not quite hard. Same for valve cover grommets. pan cover were a little firm (they probably have been changed)


I took off a 'T' line at the rear that looked to be the PCV. I dont recall any valves?? No sponge filters? No wonder these burn oil.


Anyway, since I had bent head bolts, I need to order some new ones. I will get my buddy out here to help me get things back together. I should have her back together in a few weeks. Time and physical ability permitting.
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post #14 of 24 Old 05-30-2020, 06:39 AM
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Man, thats good news for you Jimmy!

'00LMTD-4.7l,242hd,D30,D44A,3.73's,True-trac front,Spartan rear,4" short arm lift,JK'sW/32's
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post #15 of 24 Old 05-30-2020, 02:57 PM
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Quote:
Originally Posted by Bigrigr View Post
I've got about 160K on this so far, but it sat for two years untouched before i drove it home, so i may have a little more trouble than most with these seals. I looked at my PCV valve today and it was dry as a bone in the vacuum hose, so no oil eating going on there...Gotta be the valve guide seals...


thats good news for me 97Mule. Hope mine turns out that good....Just not looking forward to the passenger rear cylinders..
I would only notice the blue smoke after idling for a few mins, but normal city driving i couldn't. I had about 200k at that time.... going on 230k now with a occasional miss fire code for the last couple of years... maybe its time for gaskets and valve job or a ls swap!


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