Valve Cover Sealant

[Sharecropper]

Hi everyone. I'm preparing to swap valve covers on my new P400 long block, and noticed that AM General did not use a gasket under the valve covers when they were installed at the GEP factory, but instead used some type of industrial-strength gasket sealer instead. Anybody have any idea what this product is? Evidently it is good stuff because GEP has built hundreds of thousands of 6.2 and 6.5 engines for the military. I purchased new Fel-Pro valve cover gaskets but now I'm thinking maybe I should just use the sealant by itself. Any ideas?

Thanks.

 

[Barrman]

Permatex Right Stuff in the aerosol can works real well for that. The thing to remember is the length of the valve cover bolts. If they bottom out in the bolt hole. Then the chances of cracking the head at that spot go up. So, lay it on thick if not including the gasket.

I use the gasket and Right Stuff just to avoid the cracked head chances. No leaks yet.

 

[simp5782]

I use Dirko grey sealant. Good for offshore drilling rigs and will seal out even saltwater. They did a demonstration of sealing half a box and oil in one side and salt water in the other. Sat for 10 weeks and never mixed.

 

[NDT]

I would use the Fel Pro gaskets. Seems like when you silicone two parts together directly, it becomes nearly impossible to get them apart, no big deal with castings, but you tend to bend up the valve covers prying on them. I assume you have to change the valve covers to suit the CUCV CDR system?

On a side note, that picture of your incredible P400 in front of your slightly out of focus 1028 is worthy of an award for artistic photography or something.

 

[Sharecropper]

I would use the Fel Pro gaskets. Seems like when you silicone two parts together directly, it becomes nearly impossible to get them apart, no big deal with castings, but you tend to bend up the valve covers prying on them. I assume you have to change the valve covers to suit the CUCV CDR system?
On a side note, that picture of your incredible P400 in front of your slightly out of focus 1028 is worthy of an award for artistic photography or something.

I'm still struggling with the decision to use or not to use the gaskets. I bought some Permatex Ultra High Temp Black Gasket Maker a few minutes ago and the instructions said nothing about using a gasket. Hoping more fellow SS guys will chime in.

I am swapping the valve covers side-to-side because the P400 came from GEP with the CDR valve opening on the passenger side. I plan to move all my stuff from my original 6.2 over to the P400, and my original CDR valve mounts in that position, but does not penetrate the valve cover. My original CDR gets it's crankcase air from a 1-inch hose off of the oil fill tube and then breathes into the side of my intake. I need the P400 valve cover with the CDR hole on the drivers side because that is where I plan to mount the Spinner centrifical oil filter, which gravity drains down into the head after cleaning the oil. I plan to photo-document all this in my rebuild thread over on the CUCV Modification forum.

Thanks for the compliment on the photo. It was by accident, I can assure you. I am no professional photographer by any stretch of the imagination. The setting sun just happened to be shining through the door and my camera was sitting there so I took the shot. Here's another photo which shows more detail on the P400 girdle and cast aluminum oil pan -

 

[cucvrus]

I use the Permatex Right Stuff on just about everything. I buy it in a standard caulk tube. I had several of the aerosol cans fail and they are not cheap. I just let a curly on the caulk tip and break it off each time. Good Luck.

 

[Jericho]

hands down best i have ever used Fuji Bond. Japanese product, any tuner shop will have it

 

[nyoffroad]

I like Permatex too, I usaully apply it and assamble the parts but leave the bolts loose for awhile (sometimes overnight) then tighten them up, that way I seem to get a good seal without squishing it all out and bottoming out bolts. I never heard about the valve cover bolts cracking heads!

 

[patracy]

I never heard about the valve cover bolts cracking heads!

Any blind hole in a casting has the potential to crack due to hydraulic pressure. Fluids don't compress much at all. If the fastener thread is able to make a air tight seal, the only "buffer" in that hole is the air that was trapped under the fastener. If you run out of space and start compressing the fluid, that's when it decides to find another way out....

On a different note, I've used this principal to my advantage in the past. When removing a pilot bushing from a crankshaft, I filled the hole and area behind the busing with grease all the way to the end. Then turned a rod down just small enough to fit inside the bushing. A whack with a sledgehammer forced the bushing out. (And grease all over me, but I'll take that to get a stubborn bushing out!)

 

[ken]

When I swapped heads to NA on my GEP back in the spring I used both. Mainly as stated before. When using only silicone you can easily bent the covers if you need to take them off later. I used silicone very lightly and mainly in the spots where the casting had imprefections. Hoping to fill them so the gasket could be squeezed evenly. I have had no leaks at all so far.

 

[nyoffroad]

..On a different note, I've used this principal to my advantage in the past. When removing a pilot bushing from a crankshaft, I filled the hole and area behind the busing with grease all the way to the end. Then turned a rod down just small enough to fit inside the bushing. A whack with a sledgehammer forced the bushing out. (And grease all over me, but I'll take that to get a stubborn bushing out!)

Did about the same thing to remove a round lead ball stuck in a .54cal muzzle loader that had already had a screw broken off in it from a ball puller.

 

[richingalveston]

I had a blow out on my new head. bolt was really drilled off a little and there was no side left to hold the bolt. I wont use the Permatex sealant anymore. I also had leaks with it on my 6.2.

I used felpro cork gaskets with the high tack gasket sealer, it is red supposedly an aviation gasket sealer. I have been using this on all my gaskets for couple years and no leaks. will come apart easy and cleans up with brake clean

you will bend the valve covers up trying to get them off when Permatex is used. it works well but make sure your bolt holes are clean and also your surfaces have no oil. one little drop of oil and the Permatex will leak.