Oil Pan Seals & Sealant - Anyone use just silicone?

[John_Heard]

I've always used gaskets for my oil pan in the past, but decided on this next build I'm going to try the silicone only deal with something like Permatex Ultra-Black. Those of you that have had good luck with that, are you letting it dry some before assembly, or putting together wet?

I was thinking of putting it together wet, but let it set up an hour or so before tightening the bolts that way it's adhered to both surfaces.

This pan I'm using which is a custom one made by Charlie's, is a real pain to get the inner bolts in as they have to pass through the inside of the pan. I broke down and spent $40 on some fancy Moroso oil pan studs that have a bullet nose on them. I swear I had to take the pan off 2-3 times last time by dropping the dang oil pan bolts inside the pan before I finally got it together when using Socket Head Cap Screws.

Anyways, just looking to see what others are doing that has worked good for them.

[JES]

Hi John. I like the Fel-Pro perma dry gaskets best. But if I were to go silicone only I would use Permatex (The Right stuff) and put together wet.

[John_Heard]

I'm a bit scared to use the right stuff on a light weight oil pan, I use it on the china rails on the intake, that stuff is pretty wicked.

[mytmouz]

Hi John. I like the Fel-Pro perma dry gaskets best. But if I were to go silicone only I would use Permatex (The Right stuff) and put together wet.

The way to go for me here as well, if I went gasketless...

[supernova]

I know my pro-mod friends are gasketless but I'm not sure what selant they use. I'll ask.......

[John_Heard]

Gave the nothing but silicone a try on the pan gasket.

I decided to do a pressure/vacuum test on the crankcase to see if it was sealed up as I went to a lot of trouble with new high zoot double lip seals, etc. this time around. Got a low psi regulator hooked up, and it wouldn't build pressure. Uh Oh...

Chris found the leak at the front of the pan. Apparently when I laid the bead down I followed the marks on the block where the old gasket was with the silicone bead. But... up front where the OEM pan tapers in, the Charlies Dry Sump pan does not, it has a right angle so I didn't get it in the right place result was a major leak. Hopefully I won't repeat that one again, I think this time I'll lay the bead on the pan itself so I don't miss!

The good news was I found it before dropping the engine in the car. Bad news was I had to take the pan back off and start over.

One thing I did notice was that the Ultra Black I used still had not fully hardened at the rear main seal, that's a pretty thick cross section there. It was still uncured in places on the cap groove. It had 11 days to cure, so it wasn't a matter of waiting long enough, and humidity is high enough there shouldn't have been a problem.

I think this time around I'm going to use the "Right Stuff" and see if that doesn't work a little better.

[ytnova]

I use the right stuff on the intake valley and it sticks like crazy, I can't imagine how hard the pan will be to take off.

[John_Heard]

Hmm, I was wondering if the Right Stuff might be too hard to take off.

I do know if you can leave enough room to get a knife in to cut the seal it's a lot easier to get it off. If you tighten it so much that you can't get a knife in between the block and pan it would be real tough. I'm going to think some more about trying the Right Stuff, just picked up can of it for this evening too

[John_Heard]

I chickened out and went back with the Ultra Black. That Right Stuff just didn't seem like a great idea after thinking about it a bit more

Anyway, pan's back on. I'll give it time to cure and retest. Hopefully that got it this time.

[Craig W.]

I used the Right Stuff on my pan and it was no problem at all to get off. It seals great and cleans up easy when you have to pull the pan back off. But it wasn't hard to deal with. I finally have a motor with zero leaks.

[John_Heard]

Lol.. I'll file that one away for next time.

I'm sure the ultra black will work fine, was just hoping to find something that cured better / quicker in thick areas like that rear seal.

I was also told about 1 hr Tub & Caulk from Home Depot, not sure what brand. Guess that's what some of the guys are using between rounds tear downs that have to set up very fast.

Won't be long and Frank will be back in the car.

[John_Heard]

Leaks strike again. Got the pan back on, pressurized the crankcase and found the rear main seal leaking like crazy at the top, right at the crankshaft/seal 12:00. So much for the fancy double lip super duper seal I stuck in it.

I'm getting pretty good at getting the pan off with all that silicone on it.

We put the pan on Thursday evening and let it sit till Sunday to test, when I pulled the pan off the silicone was not setup good in the rear main groove (ultrablack). I think this next time I'm going to put a regular rear rubber seal in it, that thick cross section of silicone back there just takes too long to setup good, doesn't get enough air to cure well.

Good news is coolant system is sealed tight, no leaks there.

Oh, and found I have valve train issues now. Apparently the installed height got changed on the intakes when the heads were redone enough that I can't back the adjusters off enough. So, either going to have to shim the stand up some or get another set of intake pushrods.

Ain't this engine stuff fun...

[Craig W.]

I used the rubber end seals on my pan but used sealer on both sides of them.

How much air pressure were you using in the crank case? If the seal is meant for vacuum, then that might be the issue. It might be sealed if you pulled a vacuum.

If the geometry is correct with the current shims, changing pushrod length is the best option. Certainly the more expensive option unfortunately.

[John_Heard]

I'm using a Maximum 5 psi with a low pressure regulator, and yes, I thought about that too as the seals are made for vacuum. I do have a vacuum source, and the lowest I could pull it down to is 1 in hg, but the pump doesn't have a lot of volume. The pump can make 15 in hg if everything is sealed up decent. Best I can tell is there is something wrong with the seal as none of the other similar design seals on the front crank or cam are leaking at the same psi.

Yeah, I agree on the pushrod length that would be the proper way. I just thought I'd take a look at shimming the stand before ordering all new intake pushrods. If I can shim it a little and the sweep looks good would save a lot of money. I'm not sure right now how far off they are. Once I saw the problem last night I decided to quit and take another shot at it tonight.

[Bruce69Camaro]

Hey John,

Don't know if this will help or not, but when we need to test one of our units, that has fresh RTV (we use the red, high temp stuff) we will take a heat gun and warm up the RTV to help it cure a little faster.

Of course, when we fire the boiler up, the RTV gets cured real fast!