258 Valve cover Question

[bones]

I am going to change the plastic valve cover on my 83cj5 AMC 258 i6 / 4.2l to a chrome one. Found out there are no threads in the holes. Is this normal or do you have to tap new threads?

Also need to get rid of the studs in the middle of the valve cover.Whats the right way to do it? Cant tell if they unscrew.

Last one. What is the procedure for adjusting the the valves?

Thanks Bones

 

[CJ]

Can't help you with your question (I don't know jack about I6's), but some one will be along soon who can - I just wanted to say :ww: to the site!

 

[54cj3b]

threads are in the head not on the cover

 

[dslywalker]

Most likely you will have to drill and tap 1/4-20 holes in the head to match your valve cover in the front and back of the head to get a good seal.There should be some 5/16 holes in the head that are not threaded.You have to use a 5/16x18 bottom tap to use these holes.The studded rocker arms will have to be replaced with Omix-Ada Part # MRM1718 should be available thru Morris 4x4 one of our sponsors.I just bought one of their valve covers and got the instructions from it.
Mike

 

[Cheepjeep85]

you don't need to adjust the valves on a AMC 258 i6 / 4.2l , like you would on a 350 or something you just torque them down to 20 ft lbs if i remember right and go with it.

 

[IOPort51]

If you do have to drill and tap the head, be oh so sure to drill and tap straight. If you are just a slight degree off it will be difficult to put the bolt in and to make it seal. I suggest a drill press at very least, in other words don't try to drill it in place with a hand drill.

Most likely you will have to drill and tap 1/4-20 holes in the head to match your valve cover in the front and back of the head to get a good seal.There should be some 5/16 holes in the head that are not threaded.You have to use a 5/16x18 bottom tap to use these holes.The studded rocker arms will have to be replaced with Omix-Ada Part # MRM1718 should be available thru Morris 4x4 one of our sponsors.I just bought one of their valve covers and got the instructions from it.
Mike

 

[dslywalker]

If you do have to drill and tap the head, be oh so sure to drill and tap straight. If you are just a slight degree off it will be difficult to put the bolt in and to make it seal. I suggest a drill press at very least, in other words don't try to drill it in place with a hand drill.

I think that was a worst case scenerio.Beings he has a 83 there is a bolt front and back on my 83 head. I'd drill the valve cover to match the head if you can. The valve cover I bought from Omix is already pre-drilled to match those bolt patterns.You just have to deal with tapping the holes on the side.Which are already drilled Just get all the metal shavings out after tapping
Mike

 

[IOPort51]

There is something not right with this whole deal. You should not have to re engineer the head to match an after market valve cover.
Thats silly!!

 

[dslywalker]

There is something not right with this whole deal. You should not have to re engineer the head to match an after market valve cover.
Thats silly!!

Some heads you have to drill.Depends on the valve cover maker.Omix-Ada brand you don't have drill but have to tap..Why Jeep never tapped those holes on the side of the head who knows.I checked on a few before I bought it.Course you have to take out the studded rocker arm bolts and replace with other bolts.They were located in the middle of the old cover.
Most of what I got here was from the instructions from the valve cover.
There's some chessy ones out their.I've seen them drill the valve cover and mate it with the hole in the head on one brand.Parts guy who sells them at Morris 4x4 said good luck there all different.
Mike