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Repairing a Rotted Valve Cover 4.0 OHV


From the looks of it seems like that even with judicious heat control it would just be burning through.
Meh I'm an optimist...or maybe just a glutton for punishment lol...Id try anyways
 
Meh I'm an optimist...or maybe just a glutton for punishment lol...Id try anyways

With as scarce as the damn covers seem to be I do suppose it may be worth a shot.

Seems crazy nobody makes replacements.
 
Once you get outside the rust belt you will have no problem finding one. There are probably many thousands of good 4.0 valve covers in junkyards in the south and west. Problem is most places want to sell them with an engine, if the engine is still good, you want to keep those parts covered up while in storage... places that will sell them separate are probably not interested in shipping any parts.

I would just scrap the thing. I don't think I'd trust JB weld on a critical part that looks like that and it will be difficult to patch unless a skilled sheet metal welder is involved.
 
With as scarce as the damn covers seem to be I do suppose it may be worth a shot.

Seems crazy nobody makes replacements.
Yea I'm surprised too, with CNC being so common nowadays, along with water jet and even 3D printing. Machined aluminum would be nice, I'd buy a pair.
 
When I had a ohv 4.0 I wondered why there wasnt any cast alloy covers made by the aftermarket. My drivers side was bad too, didnt leak much oil, but enough that youd smell it burning on the manifold when youd get out after a drive, only down a qt every 3,000 miles so really not much more than normal oil usage.
 
@Blmpkn I don't need another valve cover, I just wanted to fix this one up.
Further, I just scrapped it. I have other things I need to do in my life than work on this. Thanks anyways guys.
 
When I had a ohv 4.0 I wondered why there wasnt any cast alloy covers made by the aftermarket. My drivers side was bad too, didnt leak much oil, but enough that youd smell it burning on the manifold when youd get out after a drive, only down a qt every 3,000 miles so really not much more than normal oil usage.

Exactly, that's why I went online and searched everywhere, and on eBay I finally found one, it was a junkyard cover but salvageable. And mine was rusted out and leaked on the manifold after a long drive also.

Here's how it was from junkyard, before and after pics.

75030


75032
75033


75034
 
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Here's the old one, as you can see the leak.

75035
 
The driver side cover can be repaired with enough determination & patience.

I was in the same boat about a year ago (not quite as bad as your rusty cover pic, but leaky enough above #6 cylinder to burn a plug wire).
Here's a picture of my solution: cutting off the old flange, using it as a template for a new flange made out of 3/16" stainless flat stock.

It was my first stainless welding job that wasn't exhaust pipe. The whole project took about a week of nights, at least 20+ hours. It failed multiple leak tests until I got everything stitched sufficiently, with plenty of burn-throughs. I'm glad I sandblasted thoroughly, which revealed pinholes below the PCV port that also leaked.
Even with short stitch welds, the whole thing warped horribly and shrunk across the short side. I over came that with a couple hours back and forth to a 50ton press to spread the long sides back into spec. Then another few hours with a hammer, a vice, and finished with a flat file for a uniform sealing surface.

Quite a challenging project, but 11 months and 5,000 miles later, I'm happy with the result. Leak free and still looking good.

If I were to do it all over again, I would still have cut off the old rusty flange, but I would have made the new one out of 1/8" mild steel. Grind off the upturned outside edge, then find someone with a bandsaw to cut it off as straight and flush as possible. Use the old flange as a template on a single sheet of steel for the outside edge, then the valve cover shell as a template for the inside edge to be welded. Carefully cut out the new flange with cutoff wheels and/or jig saw, but leave a couple webs across the middle for stability until all welded up. Tape the PVC port, and fill with water to check for leaks. Finish weld, leak test, repeat. Check for flatness with a good straight edge, table saw platen, or surface plate. Cut out the webs, then drill the mounting bolt holes. Surface prep, prime, & paint.
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Edit: whelp... for some reason the car-part.com link didn't work.... but there had to be a dozen or more listed in good shape.

View attachment 74995
This is a right side cover.
 
This is a right side cover.

Yeah I know. I bought the left one from him on eBay a few weeks ago. If I couldn't find the left, I woulda used that one on the left side. A friend said it would work. But no PCV inlet. Your thoughts?
 
wow! those are beautiful covers that dude makes
 
Morana makes all kinds of stuff for these too including valve covers but they are stupid expensive.


Those Remond ones are like a work of art and really are priced pretty fair. Custom lettering even. I wonder if he could cast a picture of my face into them.................... hmm............
 

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