83 CJ7 258 valve cover problems

[aharley1]

I tried three times to get my valve cover to quit leaking, even purchased a new (plastic) cover. I finally took it to a Jeep shop. Three trips, five weeks and three gaskets later, it was still leaking. His reason was that incorrect head bolts had been installed and pushed the cover to the RH side a little. Finally they got it cured by smearing calk around the outside of the lip. Anyone heard of this? All of the head bolt heads look to be the same size. He said they should be studs.

 

[JR74CJ5]

Unsure as to why a "Jeep shop" wouldn't have just corrected the bolt / stud problem... Instead using Caulk... Also the caulk... Possibly Perma-gasket? The liquid gasket maker stuff? Usually red or blue. Not sure what actual caulk will do after a while...

I would look around the net for top view photos of a AMC 258 i6 / 4.2l uncovered and compare, or maybe someone here with one will chime in...

I guess it is "possible" a wrongly used bolt would have too big of a head to keep out of the way. Then you have to think if it was like that when you got it perhaps it was a "fix" the PO didn't tell you about??

Don't think I'm an experienced jeeper yet or nothing... Just my .02c

 

[MN CJ7]

Sorry....
Our long I6 engines are known for leaking on any surface that is not suppose to leak. pan, valve cover, manifolds. All take special care and if not taken its a shoot.

I like the Permatex High Tac, my bud works for them and he turned me onto it. Its a tacky material used to hold gaskets in place during assembly and holds the gasket in place better the RTV or our fingers. Use High Tac on one side of gasket. Place on the cover and press into place. I used the Permatex RTV on the engine surface and circled the holes. Much easier to assemble. RTV on engine vs the cover is less likely to get RTV on the valve train.

For guys that have stamped metal covers... the holes get dished from fastener pressure.... use a ball peen hammer and the edge of wood work bench for support and flatten the dished area.

Hand tighten the fasteners and go away for 24 hrs or more. This allows the Permtex HT and RTV to set up... if done w/o the wait period it all squeezes out... so wait....... The with a torque wrench snug up the fasteners slowly to set jumps with the LOOK UP Torque Value for your yr & cover as the stop point. The stamp steel cover is 36-60 in# for example... the plastic is most likely less. Do not over tighten or all the temp cycles given for the set up will be gone and it will leak. A shop is never going to let it sit a day or two to set up and then carefull snug it all up.

After a few uses... temp cycle... ck fastners with a torque wrench again.
Us the Felpro 1 pc permium gaskets.

Snug up....... start in center and work you way out to ends in a CIRCLE Pattern. This is true for oil pan, Valve cover, manifolds. Center Circle pattern working your way to ends. True for the head install too. State at the ends and it will mess you up.

Your engine manufacture will be stamped on a flat milled spot on the block just in front of distributor passenger side for the AMC 232 i6 /AMC 258 i6 / 4.2l
Here is your head and year info.

Here is the first one (copied verbatum from an AMC techical service bulletin):
CYLINDER HEAD BOLT INSTALLATION CAUTION Cylinder Head Bolt Installation Caution On 1980-87 Chrysler 4.0 & AMC 258 i6 / 4.2l EnginesChrysler (AMC Jeep) AMC 258 i6 / 4.2l (AMC 258 i6 / 4.2l CID) engines manufactured from 1973 through 1980 use 1/2 diameter cylinder head bolts that are torqued to 105 lbs.ft. The number 11 bolt requires thread sealer to prevent external coolant leaks. As of the 1981 production year, all AMC 258 i6 / 4.2l (AMC 258 i6 / 4.2l CID) engine head bolts have been reduced to 7/16 in diameter. These smaller bolts should be torqued in sequence to 85 lbs.ft except for the number 11 bolt which requires only 75 lbs.ft. Again, sealer is required on the number 11 bolt to guard against external coolant leaks.The 4.0L (242 CID) engine introduced in 1987 and used in Jeep trucks uses the same torque pattern, but require 110 lbs.ft. of torque for all but the number 11 bolt. Torque this bolt to 100 lbs.ft. after applying a pliable sealer.For additional information see AERA Technical Bulletin: SB 112 The AERA Technical Committee

 

[aharley1]

The stuff they smeared is grey. It just sounded sort of fishy to me. Why would someone go out of their way to find the wrong bolts to put in? The head bolt heads do look big, but he said it was just the center 3 that were the problem.

 

[aharley1]

Thanks for the info. Your source says nothing about the center 3 being studs instead of bolts or different sized bolts. i think the guy that worked on mine is blowing smoke...or soemthing else.

 

[MN CJ7]

The early jeep AMC 258 i6 / 4.2l have 1/2" bolts for the head and is considered heavier and desirable.

You can tell the age and engine head by the info above. The rocker arm types and push rod lenght also very by year.

It is possible the engine was modified so they could have use a different head. Drilled the head mtd holes so it could use the larger 1/2" hardware. Just guessing....That is why I gave some info of the head and then info on the engine date of mfg & engine specs by the distributor.

I guess time to take some pics.

I also have the info on rocker arm types and mfg time also.

 

[hagar]

some of the replacement valve cover "kits" came with either 2 or 5 head bolt/stud combination bolts; nuts were used on the studs to clamp the cover.

 

[aharley1]

Thanks for the info. I'll do some checking.

 

[Jeepers Creepers CJ]

I have the same Valve cover leaking problems as well. I decided to go with the metal stamped one instead. Its a little more work than just replacing the plastic one. I have to tap new threads into the head without going to deep and getting into the water jacket, but when its done it will look good and no more leak.... Until it springs up some where else. Its a Jeep, they like to mark their territory like most animals.

 

[Rescue Diver]

Thanks for the info. Your source says nothing about the center 3 being studs instead of bolts or different sized bolts. i think the guy that worked on mine is blowing smoke...or soemthing else.

I've not seen any AMC 258 i6 / 4.2l that has factory head studs? Every one I've worked on, and even the newer 4.0 engines have bolts. The 4.0 bolt heads(tops where the socket goes) are a smaller diameter even though the shaft is still 1/2" like the pre 1980 AMC 258 i6 / 4.2l . When doing the 4.0 head swap, I found that I had to run the head bolts from the 4.0 under the valve cover because there wasn't enough room for the larger AMC 258 i6 / 4.2l bolts heads. The 4.0 head bolts that go on the outside of the valve cover on the manifold side of the head do have smaller studs that sick up off the top of them for bolting on other accessories, but they aren't actually studs that bolt the head down.

I agree with you that the guy that worked on it was blowing smoke. He's probably never taken a complete engine apart before, and he saw some 4.0 head bolts at some time and thought they were studs.

Maybe your replacement valve cover isn't made very well?

It's been a couple weeks. Have you learned any more? Is the leak fixed?

 

[hagar]

1.063-1 is head bolt/stud
1.068-2 is nut/retainer



listing of headbolts, refer to ones listed for SIX


shows the lip nut/retainers


footnote 1-29 explaining nuts/retainers

 

[Rescue Diver]

1.063-1 is head bolt/stud
1.068-2 is nut/retainer

But that's not an actual head stud like one that would bolt into the block and the head would slide down over the top of. Those are the ones I was talking about that go on the manifold side, outside the valve cover. They're just a regular bolt that has a stud attached to the top of the head for adding on some other accessory. The heads on those are actually a smaller diameter and take a smaller socket than the regular AMC 258 i6 / 4.2l head bolts that came on my 79 CJ.

 

[hagar]

They are actual cylinder head bolts. As such, you torque them the same. Socket head size has nothing to do with it. The retainer nuts thread down onto the studs and help clamp the valve cover.

 

[Rescue Diver]

They are actual cylinder head bolts. As such, you torque them the same. Socket head size has nothing to do with it. The retainer nuts thread down onto the studs and help clamp the valve cover.

Well yeah. That's what I was saying.

I never said anything about them needing different torque? I pointed out that they aren't actually studs, they're bolts, and the head diameter is smaller than the stock 1979 AMC 258 i6 / 4.2l head bolts, so they might clear his plastic valve cover better so it'll line up and not leak. But then again, his engine has the plastic valve cover, so it's a post 1980 engine, so it'll have 7/16" head bolts, so the 4.0 1/2" head bolts won't work on it anyway. Never mind....

 

[aharley1]

Thanks Guys. It seems to be fixed. I have a couple of hundred miles on it and so far so good. I won't be going back to that guy again, tho.