After Market Valve Covers

[mudkicker715]

It was metal aftermarket. leaked as bad as the plastic

[carnuck]

If it's the correct shape, I'd redo it with the "Right Stuff" sealer.

[swampduck2]

Yup. Der. Plastic. My brain has been farting a lot lately.

[SvenTomas]

Gonna do my part to keep this impressively long thread alive.

I just replaced my factory plastic valve cover over the weekend with the Black AL one from Collins Bros. 

Leaks like a geiser now.  I did not use sealant between the head and the gasket (as they advised).  Got talked out of it by an excellent mechanic friend of mine.  Anyhow, that's not the worst of it.  The rear-most  hole in the driver's side has completely stripped out.  I think I did a poor job of tapping the existing hole there, and now I need to figure a plan to fix that hole.

Any ideas on what's best?

Heli-Coil?
EZ-Lok? (3/8" od 1/4" id)
Drill and tap to 3/8 and look for a 3/8 - 5/16 or 3/8 - 1/4 automotive stud to put in there?
javascript:void(0);

[ammachine390]

When I drilled the holes in head, I accidently stripped them out as well. I drilled the hold a little bit bigger, and then used a helicoil to fill the gap, since I couldn't use a larger bolt. The only thing was, the helicoil was a little too long for the hole in the head, and you can't drill the hole too much larger than it needs to be, So I used a wire cutter to trim them down a little so the helicoil depth matched the depth of the hole in the head. It worked well, and have not had any leaks yet after about a year and half and probably around 1500 miles.

[carnuck]

helicoil is what I did

[SvenTomas]

Thanks for the input.  So, I just spent nearly an hour searching for past info on just how deep can you drill a hole in the head.  I didn't find any references.

I intend to use a helicoil on my stripped hole (so that I can use the original specced 5/16-18 allen-head machine screw.  The standard  helicoil length is about .40", and the hole needs to be a bit deeper to allow room for a tap (even a bottom tap requires extra room below the bottom of the helicoil).

Anyone know how deep one can drill??

Thanks
Tom

[Prafeston]

Ok, I did the valve cover upgrade today.
Yesterday evening I glued the cork gasket on the cover with sealant.
Put it on a flat surface and put some bricks on for weight. Left it to dry overnight.
This morning I first removed the old valve cover.

1. I removed air filter, carburettor and a bunch of vacuum hoses.
2. I removed the wipermotor, this is really easy, four plate screws and a clip (good tip from the nest).
3. Hung up the wiring loom with a piece wire on the underhood courtesy light.
4. Removed the bolts from the cover and took it off.

The bolt holes on passenger side had 1/4" heliciols and the bolts supplied were 5/16", so I used 1/4" ones with a washer.
The bolt holes front and back were 1/4", same as bolts supplied with the cover.
On the drive side were only two holes that had to be tapped.
I drilled them a little deeper to 1/2" deep (the bolts supplied need a hole a least 5/16" deep thread) and than threaded the hole with a machine tap. Since the head is cast iron, it cuts like butter. I used the family vacuum cleaner to remove the metal shavings.
It put a thin coat of sealant on the cilinderhead. If you have AC, it needs a little lifting of the AC hose to get it on.
It put the bolts in and did not tighten them right away. The bolt near the firewall is a problem to get in. I succeeded on the second try. I used an angle grinder to make the bolt pointed and used a small file to cut the thread a little deeper.
This is and old trick to make self centering bolts. It went straight in. Than I tightened the rest.
The grommet supplied for the PCV was to big. I increased the diameter of the PCV-valve with a piece of garden hose and sealed it on with heat shrink hose for a nice tight fit. Put everything back on. and make a test drive. Now it is oil tight.
In total it took me about 4 hours, incl two coffee breaks (we Dutchmen drink a lot of coffee).

This is some good stuff from an earlier post in this thread.

[SvenTomas]

Great . . . thanks for posting.  I must have missed his reference to 1/2" deep on my read through.

I just did find another reference in a jeep forum to 'just a hair deeper than 1/2".

[Bird-o-Prey]

I have an aftermarket aluminum head cover on my eagle.  I used black ATV (forget the name right now) on both the head and the cover.  I put the sealant on the head cover and attached the gasket.  Let that dry until it was stuck on good (but not cured).  Applied sealant to the head and then dropped the cover in place.  Tightened all the hex key bolts and let it set up.  After 2 years, the headcover started to drip oil again at the rear and rear passenger side.  So, I tightened all the bolts again.  Some of them had worked themselves loose to the point where they were only hand tight.  I have had to tighten the bolts a couple of times over the last year.  Finally, I pulled the bolts one at a time & sprayed brake cleaner into the bolt hole, then blew it out with compressed air to clean the oil out.  Cleaned the oil off the bolts and put a drop of blue locktite on the bolt and then torqued them down again.  The rear bolt is a BEE-ATCH to get at and I finally modified an Allen key specifically to get to it, by cutting it down so it just clears the head cover when tight.  I was leak free for a while, but the rear bolt has vibrated itself loose.  I think I am going to apply a lock washer to that one.

The point is, even with sealant, the engine will vibrate the bolts loose and you will have a leak after a while.  It is only a matter of time.  I think this should be viewed as an ongoing maintenance issue rather than a fire & forget solution.  I spoke with an old AMC mechanic I ran into one day.  He said that in the day, they put the sealant onto the head cover and let it cure.  Then they wiped a thin film of oil onto the head and attached the cover.  The oil allowed the cover to stay tight to the head, but let the head expand and contract under the cover.  The 2 materials expanded at different rates with heat.  The head cover had to be re-tightened periodically to keep the oil from really leaking out.

Just my POV, though.

[ammachine390]

Anyone know how deep one can drill??

I drilled my holes to the approximate distance that the screws had to go into the head. I determined how much of the length of the screw was used for the just going through the cover and the cork gasket by putting the screw the valve cover and the gasket, and the distance that was sticking out, is how far I drilled.

[1982AMCCONCORD]

About 15 years ago I had a plastic leaking valve cover. I tried to redo it myself several times and it still leaked... although not as bad as the original. A few years later... after I had the engine rebuilt... I went and bought a brand new one from the local Chrysler dealer and had the engine shop put it on before the engine was reinstalled. Although I know it will eventually leak again at some point... it hasn't leaked since... this is another reason why i want the 4.0 head. The valve cover was superior to the original 258's.

[carnuck]

Aluminum aftermarket ones are superior to the plastic ones in pretty much every way.

[eagleman]

Just started to install my aluminum valve cover today and I can't help to wonder why the new cover does not have the holes in the center of the cover where it uses a bridge stud. Seems to me that it would help to seal it better. Strange thing is the new cover comes with a new bridge without the stud to install in place of the studded bridge when in my opinion it would have been just as easy to have put a couple of holes in the new cover and use the studded bridge. I'm sure there must be a reason for this but I'll be if I can figure it out. Maybe one of you has a answer. I would sure like to know.

[Jurjen]

My original flower planter didn't have the centre bridge either, I guess that saved me from worrying about it.