Valve Adjustment

I have found no valve adjustment procedures for my 75 CJ with an AMC 360.
Are they adjustable??
Thank you
Tim

 

No. Hydraulic lifters are not adjustable.

 

Yeah, on an AMC they are non adjustable. Unless someone has done some work on your 360 and installed an adjustable valve train (doubtful). Do you ask because yours are making noise or are you just doing preventive maintenance?

 

Can you adjust them similar to a small block Chevy? Back em off untill they clatter and run em up 3/4 turn?

 

Not sure what you are thinking about with the Chevy - maybe the rockers float on their pivots above the pedestals? There's no adjustment screw on the rockers used with AMC engines. Some of the rockers are bridged (using a stamped rocker with a cast bridge between pairs) and some early ones are on a rocker shaft IIRC. Don't know that much about the early ones, but none of these have an adjustment screw.Your only opportunity to adjust is by using different length pushrods or by shimming the rocker bases, to the best of my knowledge.

The stamped rockers with bridges need to be torqued down until the bridges bottom on the pedestal. The Chevy rockers may float above the pedestal, but the AMC ones do not, again AFAIK.

Hope I included enough disclaimers ...

 

AMC rocker arms are non adjustable, many of the AMC rocker arms are just on a bolt (not a stud). Just run the bolt tight and it is adjusted.
The Chevy rocker arms are adjustable. When the lifter is on the back of the cam lobe, you take all the slack out of the pushrod, so there is no up and down movement of the pushrod between the rocker and the lifter, then you preload it with another 1/2-3/4 and sometime 1 full turn of the rocker nut. It's up to the tuner really. The amount of preload varies from person to person and book to book...the most common amount used would be 1/2 turn.
Non adjustable valve train is pretty common, but adjustable has a huge advantage. This is why many Ford and AMC owners who are building a performance orientated engine will use Chevy "style" valve train.

 

Wow thats interesting because my 401 has no bridges. It has stamped steel rockers and adjustment nut on a stud just like a Chevrolet engine. Now I'm curious either I'm missing some parts or the P.O had some custom work done to the heads. Is there any way to run the numbers on these heads to find out what I have? PM me with any info on this because I've had a hell of a time getting mine to run sweet. I can post pictures of the valve train later.

 

Yeah, if they are like Chevy, they just may actually be Chevy (it's a common trick). Also, on the bridges, if memory serves, not all of the AMC engines had them, I think they started using them in a certain year. I am not an AMC expert by any means though, Just something I remembered from a while ago.
What is your 401 doing that you dislike?

 

I have no previous experience with the AMC engines, at all.I have a lot with Chevrolet and Ford. I know my engine is an AMC but didn't know that Chevy heads would go on one if that was what wou ment by a "common trick". From all the publicity that the 401 gets in the AMC world, mine is not very impressive although I dont know the extent of the rebuild, the PO claimes that the engine was redone at some point during his owning it. When I bought it, it had an awful miss which I discovered to be a rocker arm that jumped the pushrod on #2 cylinder. In a short it runs good but still doesn't have the feel that a V8 of its calliber should have. The idle is not real smoothe and sounds blubbery when driving at highway speeds.

 

No, I meant Chevy style adjustable rocker arms, not heads.
As a performance engine builder/designer, I can tell you that if you feel that your 401 is slow...there is something wrong with it. In box stock form (in a CJ) they are a real brute. Of course it will be hard to diagnose a problem over the Internet...but I would be happy to give you any help that I can. First thing I would suggest is probably the most easy...and that is timing. Do not pay attention to the book when it comes to timing. An AMC likes a lot of advance, initial and total. Tell you what, why don't you PM me so we don't clog things up and I will give you a hand getting it running right.