A couple weeks ago I installed my new VE pump and decided while I was in there to reseal my tappet cover as well. That turned out to be a disaster. I made the very critical error of getting a felpro gasket. I got it all apart and tappet cover off. Normally I use a sealer called "the right stuff". Well I was out of it and I cheaped out and got some black RTV. The tappet cover has six bolts in the middle of it and has a rubber seal that slips over the edge all the way around the cover and uses tension to hold the seal against the block. Not the greatest design if you ask me. Not with a cover that is made of sheet metal anyways. I put rtv in the groove and let it sit for a couple hours to help hold the seal to the cover while compressing it. Put it all back together, then put the tappet noise cover thing back on and got injection pump on the next day and fired it up. I was checking all the fuel lines for leaks and after about 2 minutes of running I saw a quart of oil on the ground. After making up some new words me and my good buddy SMKHZRD ripped it all apart. We had the tappet cover back off in half an hour. (is that a record? we were impressed with how fast we work when angry) The tappet cover had squeezed about half the bottom section out and oil was going right past it. With the noise cover on it you can't see if the seal squeezed out. Went to cummins the next day and got a new seal from them. It is a different design. When you squeeze the seal over the cover, the lip toward the inside of the cover pops up a bit. This way when it is compressed it tries to push the seal in instead of out. I got some of the right stuff sealer and put some in the groove and let the seal cure to the cover overnight. The next day I put it on the truck. Since the seal was well attached to the cover I put sealer on the seal to block surface as well. And put some on the bolt sealing surface as well. Then waited until the next day to fire it up. Not a drop of oil. Right stuff sealer is supposed to be able to be returned to service immediately but I think its a good idea to let it dry/cure overnight. It's too much of a pain to redo if it leaks. And to top it all off, the felpro gasket was $19 and the cummins one was only $18. Also there are 6 rubber/metal washers to seal up the bolt holes. They are about $2 a piece so I got new of those as well. So lesson learned. GET CUMMINS THE FIRST TIME AND SAVE YOURSELF THE TROUBLE. I also highly recommend using right stuff sealer. It is expensive but it works. The first time. I use it on everything and I cant believe I was dumb enough to not use it the first time on this. Trying to save $$$ and it just cost me more $$$, time and aggravation. I tried to find more info on doing this before I did it but came up short so figured I post some info on it.

Aaron

 

Is the "Right stuff" an Anerobic sealer?

 

Right Stuff is just good silicone as far as I know. I prefer Permatex Ultra Grey or GM grey or maybe it's gray, it is as good as it gets for silicone sealer IMO.

We put a felpro gasket in dads grader(5.9), it doesn't leak, but it was all wheather checked in a matter of months.

 

Pulltilbroke-here is what they call it "elastomeric rubber gasket" it is anerobic sealer as it cures in the absence of air. I read some other forum it is urethane based.
Captain Chrysler-My original one was leaking because it was all cracked. The seal to the block was good and it was actually quite difficult to get off, but it was so rotted from heat it had cracks all over. I think the felpro one would work ok as long as you can make sure it doesn't squeeze it out somewhere. If I could have seen it and put something there to hold it, it may have sealed up. Did you use a sealer on it? Did it want to squeeze out at all while tightening it down?

 

I put the cover gasket on dry, but do use silicone on the bolt seals.

 

That sucks to have to redo a job like that. I try to refrain from using RTV along with any gasket, because it's just too slippery and just helps the gasket to squirt out from where it's supposed to be. I just glue the gasket in place with weatherstrip adhesive and call it good.

 

I use the clear 3M glue and put the gasket on the part and let it dry
then clean the block or head in this case with laquer thinner and install,
then if you need to take it off it comes right off. i have used this method on
small block chevy valve covers and removed them many many times with out
a leak at all.

 

The "Right Stuff" can almost be a permanent seal..lol. We use it all time in the heavy equipment shop, and if you ever have to take sonething back off that is sealed with it, be ready for a fight! We sealed the rearend up on a scraper once, took 5hrs and 4 guys with big pry bars to get it back off after the rearend blewup.

 

black rtv on the Cummins gasket works everytime for me. I give it about 30-45 mins of setup then pop it back on.
Yeah, that would be a pain to have to do it more than once.

 

I just got the blue felpro gaskets, sanded the lip of the rocker boxes smooth, and put them on. No sealer of any kind and no leaks. There should be enough pressure on them to seal off as long as the mating surfaces are clean and smooth.