258 valve cover gasket options

[85cj8]

Its been a few years but my valve cover gasket is leaking again , i do have the aluminum valve cover upgrade already and the current gasket that came with it , its seems a tad bit thicker than the parts store ones, so order the thicker one from like quadratech etc ? or does someone have a parts store option that will work ?, and yes i know about the extremely low torque value on the hold down bolts , thanks

 

[spankrjs]

Around post #595:

spankrjs's Biloxi, MS '83 Scrambler

TNT includes this piece to install a license plate, I guess: You can slide this tube into the tire mounting tube. I am not doing this, it would look like crap, and I would not have a tag light. So, the easiest solution to this problem, for me anyway. Made a simple aluminum angle with four...

www.cj-8.com

No leaks after I completed the initial re-torque, so three years leak free

I have also had good luck using the Fel-Pro cork gaskets and aviation sealant.

 

[85cj8]

Around post #595:

spankrjs's Biloxi, MS '83 Scrambler

TNT includes this piece to install a license plate, I guess: You can slide this tube into the tire mounting tube. I am not doing this, it would look like crap, and I would not have a tag light. So, the easiest solution to this problem, for me anyway. Made a simple aluminum angle with four...

www.cj-8.com

No leaks after I completed the initial re-torque, so three years leak free

I have also had good luck using the Fel-Pro cork gaskets and aviation sealant.

I started investigating the silicone gaskets but wasn’t sure, seems 50/50 some people love them some hate them , don’t know for sure if some were installation errors ? But most seems to have followed the installation instructions to a T

 

[Trevor Davidson]

The Realgasket silicone gasket worked great me

 

[spankrjs]

The biggest issues I have found with the aftermarket aluminum valve covers:

1) Some of the holes are not exactly centered, so some filing/test fitting is required to get the valve cover holes centered over the threaded holes in the cylinder head. (seems as the years go by the valve cover quality gets worse and worse as far as hole alignment)

2) Bolt length. I measure with a caliper to make sure I get bolts long enough to engage most of the thread depth while still compressing the gasket before they bottom out. I use metric flat washers, IIRC 6 and 8 mm, around the SAE bolts because the metric washer OD is smaller than SAE and the washers will clear cover without hitting it. Again, lots of test fitting required.

I was skeptical of the orange gasket but it is still working flawlessly. I have had good luck with the cork gaskets, but like most cork gaskets, time and heat degrade them, maybe get a couple of years out of them before they start seeping.

Just my opinions/experience.

 

[AJ2393]

The biggest issues I have found with the aftermarket aluminum valve covers:

1) Some of the holes are not exactly centered, so some filing/test fitting is required to get the valve cover holes centered over the threaded holes in the cylinder head. (seems as the years go by the valve cover quality gets worse and worse as far as hole alignment)

2) Bolt length. I measure with a caliper to make sure I get bolts long enough to engage most of the thread depth while still compressing the gasket before they bottom out. I use metric flat washers, IIRC 6 and 8 mm, around the SAE bolts because the metric washer OD is smaller than SAE and the washers will clear cover without hitting it. Again, lots of test fitting required.

I was skeptical of the orange gasket but it is still working flawlessly. I have had good luck with the cork gaskets, but like most cork gaskets, time and heat degrade them, maybe get a couple of years out of them before they start seeping.

Just my opinions/experience.

I did a valve cover placement (Crown Automotive) in the spring 2024 and encountered these exact issues. On top of the fact that the cover holes were "off", the holes in the cork gasket were also way "off." The cover and the gasket are a system and have to work together, otherwise... leaks. Misaligned holes lead to crooked bolts and it jus won't seat right. At least with cork gasket, I was able to trim out where I needed without compromising the sealing integrity. Some holes in the gasket became rather elongated. I have no idea how any of this would work with a silicone gasket.

I spent a lot of time checking the cover and cork gasket fitment "DRY" for alignment. Then I spent more time measuring and checking the bolts and hole depths "DRY". Clean the holes thoroughly with brake clean and chase with a tap if it's full of junk. The front and rear holes on mine were very deep in the head, no issues. The passenger side holes were not, and I needed a little math to make sure that I didn't bottom out the bolt based on the cover and gasket thickness. I did end up using Spankrjs suggestion of metric washers, and that worked so that I was able to still compress the gasket. The driver's side head bolt holes (if you have them) are generally deeper, but you have to check again that you don't bottom out before compressing the gasket. I also used NAPA aviation sealant, and so far no leaks.

I wasn't a big fan of cork gaskets until I did this cover. To me, it was more forgiving for the idiosyncrasies of my head. For information, the previous gaskets was just silicone or RTV. It never really formed around the cover like it should of. It was thin in spots, and didn't stick at all in others.

 

[Jeeper_4_Life]

I did a valve cover placement (Crown Automotive) in the spring 2024 and encountered these exact issues. On top of the fact that the cover holes were "off", the holes in the cork gasket were also way "off." The cover and the gasket are a system and have to work together, otherwise... leaks. Misaligned holes lead to crooked bolts and it jus won't seat right. At least with cork gasket, I was able to trim out where I needed without compromising the sealing integrity. Some holes in the gasket became rather elongated. I have no idea how any of this would work with a silicone gasket.

I spent a lot of time checking the cover and cork gasket fitment "DRY" for alignment. Then I spent more time measuring and checking the bolts and hole depths "DRY". Clean the holes thoroughly with brake clean and chase with a tap if it's full of junk. The front and rear holes on mine were very deep in the head, no issues. The passenger side holes were not, and I needed a little math to make sure that I didn't bottom out the bolt based on the cover and gasket thickness. I did end up using Spankrjs suggestion of metric washers, and that worked so that I was able to still compress the gasket. The driver's side head bolt holes (if you have them) are generally deeper, but you have to check again that you don't bottom out before compressing the gasket. I also used NAPA aviation sealant, and so far no leaks.

I wasn't a big fan of cork gaskets until I did this cover. To me, it was more forgiving for the idiosyncrasies of my head. For information, the previous gaskets was just silicone or RTV. It never really formed around the cover like it should of. It was thin in spots, and didn't stick at all in others.

I don't have an inline 6, but I use that aviation sealant on any cork gaskets and a lot of others. I used it on my oil 304 oil pan gasket that is cork and it has been holding up well.

 

[Rosco1974]

I don't have an inline 6, but I use that aviation sealant on any cork gaskets and a lot of others. I used it on my oil 304 oil pan gasket that is cork and it has been holding up well.

Aviation sealant is the best recommendation ever. Paper, cork and basically every other type benefit from it.

 

[Mancunian]

The biggest issues I have found with the aftermarket aluminum valve covers:

1) Some of the holes are not exactly centered, so some filing/test fitting is required to get the valve cover holes centered over the threaded holes in the cylinder head. (seems as the years go by the valve cover quality gets worse and worse as far as hole alignment)

2) Bolt length. I measure with a caliper to make sure I get bolts long enough to engage most of the thread depth while still compressing the gasket before they bottom out. I use metric flat washers, IIRC 6 and 8 mm, around the SAE bolts because the metric washer OD is smaller than SAE and the washers will clear cover without hitting it. Again, lots of test fitting required.

I was skeptical of the orange gasket but it is still working flawlessly. I have had good luck with the cork gaskets, but like most cork gaskets, time and heat degrade them, maybe get a couple of years out of them before they start seeping.

Just my opinions/experience.

Exact same issues with mine. One thought though, I assume everyone is using SHCS? There's not much room for anything else, but if you are not it helps.