AMC Eagle valve cover replacement

This is one of those things that you just have to do because the factory solution is crap. Apparently this was notorious back in the day, AMC just couldn’t make their plastic valve cover seal at all and it always leaked. I can see why, the flange bolts trying to clamp down on the edges of a flexible plastic lip that’s really small is a terrible idea. All that being said there are some hurdles and some of what I think are terrible ideas for how to actually install your aluminum valve cover that I’ll go over here.

keep crap from getting down there

First is to label all the vacuum lines and wires that cross the valve cover that you disconnect. I recommend masking tape flags with numbers because I used metallic sharpies and still can’t figure out where they’re all supposed to go. Second is that when you remove things like the PCV elbow that sticks in the back of the valve cover, remember where you put it. The auto part store does not have an exact replacement any more and you’ll have to grind it down a lot until it fits. Third is to plug all holes where the push rods go with excessive shop towels, seriously nothing should get down there and if it tries you should gently vacuum it back out.

scotchbrite scrubbed

After you remove the valve cover I recommend scrubbing the surface with a scotchbrite pad soaked in mineral spirits. It will help get any oily baked on gunk off so the new gasket can seat. Once it’s clean you can then get ready to tap the two un-tapped holes. Originally I think these were used for locating pegs in the plastic valve cover. Some people have reported that you have to drill them out to a certain size and tap them for 1/2″-13 bolts. The kit I got had 5/16″-18 socket cap bolts for all the large holes so I tapped them for that. The holes were already large enough to take that tap without drilling (it had me a bit nervous that it would be too sloppy). I first ran a regular tap, then a bottoming tap, the top of the hole has a slight chamfer so a starting tap really isn’t needed. Be gentle so you don’t strip them out, but be sure to go all the way to the bottom. When I did this I had circular ring magnets stuck to the head so the chips stuck to that and I still vacuumed out the remaining bits. You can also use a thick grease to catch the chips, but cleanup will be harder.

thin metal tubing taped to the end of the vacuum will get down in that hole to clean it out, that and brakleen

When installing the gasket I used a generous portion of high tack gasket sealant on both sides of the cork gasket, it was really helpful in keeping it in the right position when tightening because some of these edges are very thin. If at all possible install this valve cover on an engine out of the vehicle. The clearance between the firewall and the head is not that big and I had some trouble squeezing it in there, but it can be done. The paint on the back of my valve cover is now a bit scraped up but you can’t see it anyway and the aluminum isn’t gonna oxidize any more because of it.

this works rather well

The only trouble I had when reinstalling the cover was the rear bolt. It’s one of the 1/4″ ones and getting a hex head in there to tighten it was almost impossible, getting a torque wrench on? how could you even do that? Well, as you can see, through a series of adapters I managed to get my torque wrench on a flex shaft and on to an allen head socket adapter all seated and torqued down. There are instructions that will tell you to drill a hole in the metal lip over top of the bolt, but that’s the tray that carries rainwater away from the cowl, you can’t just have holes in that. This is a far superior method for tightening that last bolt. After all that effort, did it work? does everything look and run smoothly?

Oh yes!

This thing will eat years old gas through a rusted out hard line and just not give a crap. I think I stripped out one of the aluminum tapped holes where you mount the solenoids but I can drill and re-tap that for a bigger size. Be aware that the bolts they ship that with may be too long so don’t force it, just add washers or grind down the bolt.

One Response to “AMC Eagle valve cover replacement”

  1. My new car! | Evan's Techie-Blog Says:

    […] Valve CoverĀ upgrade […]

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