94+ Valve Cover on older 4.0s

Okay right now I'm running a 93's valve cover on my 1990, it works good. Will the ones from like Quadratec that say 94+ work on the older motors? I have heard that on the newer ones (94+) they did away with the lip on the underside of the valve cover and it is required to have a lip to work on older ones. However, I have seen the Quadratec ones on Renix motors before. What am I missing here and/or what have you guys done? I think I remember hearing about someone that ran like an '02 Wrangler 4.0 valve cover on their 90? Anyone have any comments or tips?
TIA for any help,
Collin

My catalog says the valve cover gasket for the 91-01 HO is the same. If the gasket fits, the vavle cover will also likely fit.

I redid the valve cover gasket on my '94 Sport 4.0, and I think I remember a lip on mine. It wasn't very big (maybe like a centimeter tall?). I could be wrong.

Thanks for the help so far guys. Yeah I know my 90's originally had a lip on it and the 93's does also. I don't actually know it if is necessary to have the lip in there though, but I thought I heard from someone that the newer ones didn't have the lip. Has anyone done this swap?

Stupid question here, but why swap the vc at all? Does this help with the leaking? I know I've replaced my gasket a couple times, and it's always started leaking about a week or so after I replaced it. Just wondering.

brendon800 said:

Stupid question here, but why swap the vc at all? Does this help with the leaking? I know I've replaced my gasket a couple times, and it's always started leaking about a week or so after I replaced it. Just wondering.

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If you replaced your valve cover gasket and it still leaks it means you did not get a good seal. Which means either you didn't get the gasket sealed around it correctly or your valve cover is warped. If you're getting seepage again after a week its possible that your bolts are backing out of the holes possibly because the valve cover is warped. In my 90's case the valve cover was warped severely. When I replaced it with the 93's it quit leaking, for now. The CCV connections are also improved over the Renix ones because they are bigger and have 90 degree elbows.
HTH,
Collin

They switched to using the stamped valve cover in 96 and use a composite steel backed rubber gasket that aligns on the head bolts. Its easier to use, but is a $35 gasket. I tried to use the standard cork gasket but it diddn't work well, there is no flat surface (its curved) on the stamped cover and the gasket doesn't stay in place. The composite has a sealing ridge and is held by the studs. I don't see why you can't use a different year cast cover and use the normal gasket. Depending on what year, you will need to get new CCV fittings/elbows/tubes as they made some slight changes between years.

So by what you're saying the stamped ones should work fine on the older units as long as I'm either patient with a standard gasket or use the composite one? I've already got the CCV lines from the 93 so I think I should be fine as far as they're concerned.

What I'm saying is that the flat gasket diddn't work well on my 96, factory valve cover. The surface underneath is slanted and seems to push the gasket around, doesn't seal right- even with sealer and I'm pretty good with gaskets.

I tried the flat gasket because- it was $7 instead of $25 (with my employee discount) and I wanted to get the cast aluminum cover at a junkyard, my painted stamped one is scratched. I did not find a useable cover that day so decided just to replace the gasket and spraypaint the cover. I wound up tearing it down again to put the composite gasket on.

However- the composite gasket seats using the head bolts (or studs, don't remember) but these have pins in them to align the holes in the steel gasket, I don't think earlier heads have this.

I don't know if aftermarket stamped ones or ones used on other Jeep models have a flat mating surface or not. Also, the 96 motor has different CCV fittings than before so you will have to re-do that if you want to adapt a later stamped cover.

Oh, my CCV elbows are specified for a 97 I believe, Wrangler. They stick up farther than the old ones and punched a hole in the hood liner fabric (but I later took that thing off). It was all the dealership had in stock.

My recommendation is if you change valve covers to use a later model (HO) cover, but the cast aluminum one avaliable in pre-95 models. Which was what I wanted to install anyway!

Ok thanks.