The Stovebolt Site Forums The Shop Area Engine Shop How much of a bead to run on RTV Pan Gasket

Just curious, all tips welcome - how wide of a bead (fractions of inch please) do you run when using RTV on Oil Pan Gasket. I was thinking 2/16 but is that enough?

I'm replacing the oil pan gasket on my 1948 1/2 Ton Chevrolet Thriftmaster (motor is a 1962, 235ci)

This is my 2nd attempt, 2+ weeks ago did it, but think I put way too much RTV on, ended up leaking out of the very front of the oil pan. That time I used the rubber gaskets on the front & rear and cork on the sides. This time, I got a new gasket set, it is Cork all around (front & side strips) as was the original gasket that I removed from the motor. I don't think the rubber strips seated very well and I had way too much RTV wedged up there, did about 1/4" bead all around, used 2 tubes of RTV in the process.

2nd time is a charm hopefully, but how does 2/16 sound on running the bead?

I always straighten out the tin pan and only put silicone here, 1/16 inch does it, the CI pan rail is for sure flat and smooth, therefore should not need anything on top of the gasket. If one puts gasket material between the CI pan rail and cork gasket, one is looking at a hard and messy job removing the pan.

Ed

Thanks Ed, what does CI stand for?

I think Ed is saying, CI = Cast Iron (the block)...

Mike B

I always smear a little grease on the block side of the gasket.so it doesn't stick to the block, the next time I remove the oil pan.

I use silicone, only a small dab at the corners where th cork meets the rubber.
Then gasket adhesive, (contact cement) to attach cork and rubber to oil pan.
Finally Permatex #2 spread smoothly and very thin on top of gaskets where meets block.

Once a long time ago used silicone lightly on both sides of oil pan gasket and later had a terrible time removing the pan, never going to do that again. Mostly avoid using silicone gasket maker altogether.

I try to avoid silicone as well. If I do use it on gaskets, it will be an extreme case, and it will be a thin layer on each side of the gasket. It will make it hard to get off though, but it won't leak. I definitely don't use it as a matter of course, and most definitely not a bead, it squishes out and makes chunks that might fall off and get stuck somewhere you don't want it to get to. I do large industrial machinery maintenance for a living, and I have seen some horror stories with silicone. I rarely use it, some gear boxes get it on the covers, but I make sure there is jacking bolts to break it loose.

Attaching a gasket to the oil pan is a really good way to get a leak, no matter how careful you try to be. Stick the cork side gaskets to the block first, with some type of quick-setting adhesive like trim cement, contact cement, etc., then do the same to the end seals, MAKING SURE THE END SEALS END UP OVER THE SIDE GASKETS- - - -cork against the block, and the end gaskets sandwiched between the pan and the side strips, cork or rubber. DO NOT apply sealer to the pan side of the gaskets, side or end.

Then use a TINY bit of RTV sealer right where the side gaskets and the end pieces join. I rarely, if ever manage to use up a whole tube of RTV before it hardens up in the tube. That stuff is one of the most-over-used gasket sealers I can think of.
Jerry

I am glad you posted this, Jerry

I have recently kept out of disagreeing with posts that say to put the adhesive on the pan side of the gasket.

Your way, allows the possibility of removing the pan without destroying the gasket.

As you posted, the other way increases the probability of a bad seal at the ends of the pan.

For old iron like the relics we work on, you really need to hone your tinsmith skills to form the sheet metal to fit the cast iron. The cast iron surfaces are usually very straight. Just make sure that they are squeaky clean. Oil pan, valve cover, and side cover can be checked for fit by bolting them on without gaskets. If they don't fit tight without gaps, good luck getting them to seal with any compound. Time to get out the body hammers and fine tune the sheet metal. Take a look at the areas where the bolts go. They get abused by over tightening and need to be hammered back out. 216 and early 235 valve covers tend to get bowed outward along the sides from over tightening the 2 acorn nuts. Mash them back in by hand.
Cork is your friend. Spread a layer of engine oil on them before you install the sheet metal. If you feel that you must tack the gasket to either the cast iron or the valve cover (not both!), make sure to put the oil on the surface which did not receive the compound.
Applied oil will soak into the cork, causing it to increase in thickness, resulting in a tight seal.
Do Not over tighten the screws! That is where most leaks come from.
Carl

Gentleman, sincere thanks. I've been waiting and reading all these tips before I go back in on it. The irony in reading these, I did all of that (not to do stuff on the first attempt) I'm sure I ever so slightly bent the front left corner of the pan the first time I removed it or pried it off (need to peen it back to shape) Also, I ran way too much RTV, it was mess, ran it all around the place 1/4 inch bead, and then I tightened all of bolts way too tight.

I’ve had great luck gluing the gaskets to the pan, where it’s easier to remove them from later, and not glue to the block. Haven’t been concerned about reusing oil pan gaskets.
On y’alls advice I’ll try fixing them to the block next time, that sounds reasonable too.

Valve cover gaskets I do like I glue to the cover, and nothing but oil on the other side.
Then it’s reuseable for years.

On similar note..........the sheet metal covers leaked with new gaskets. I replaced the valve cover and side plate with aluminum parts. First two attempts with gaskets yielded small leaks or weeping. Not bad just annoying. Next........ Instead of using the gaskets........used permatex gasket maker RTV with no gaskets. Used the procedures or techniques as the tube suggested. No leaks no weeping..........


Link to gasket maker

In my humble opinion, I think the above method by Showkey is the only way to get a good seal on the valve cover. I haven't done that on mine but one day I will.

Good thread guys. Good ABC stuff that can easily frustrate us. I'm sure many of you will say it's feel, or just make it up until the gasket starts to ooze out a little bit, but for us less feely folks what do you think the torque settings on those oil pan bolts would be? Jeg's says 12 ft lbs for oil pan, 6 for timing cover and 3 for valve cover on an SBC. Think those are close enough for our stovebolts? I think it is easier to resist a 1/2 slab of smoked ribs that to over tighten oil pan bolts!

Using a torque wrench against a resilient substance like a cork gasket is a recipie for disaster. Unfortunately, it takes years of experience to develop that "just right" feel for tightening bolts on sheet metal parts like oil pans and valve covers. Assuming you've done your homework and gotten the flanges as straight as possible first, run the bolts in until you have just barely eliminated any slack, and make another 1/4 turn. Come back a few hours later, and check for any loose bolts as the cork takes a set. Snug the loose ones another 1/8 turn or so, being careful not to distort the metal or crush the gasket. After tightening a few hundred bolts that way, you'll develop a feel for it!
Jerry

Don't know that I'll ever get there Jerry, but that's exactly what we needed in the meantime. Many thanks.

One thing which helps to prevent me from over-tightening the oil pan and side cover is the "stupid" stove bolts which take a flat screw driver. This "stupid" fastener is there to out-smart us "genius" ape-armed goons, preventing most of us from over-tightening these fasteners.
Carl