manifold-block sealing

[1990LTD]

I've heard different things:

- use the little gasket "strips" that come w. the gasket set

- use a big thick strip of rtv and nothing else

- use the gaskets WITH rtv


what the hell should I do?

[DuceAnAHalf]

thick bead of RTV. let it sit for an hour before you install the manifold.

[1987cp]

I was reading about this recently. Fel-Pro's MS-93334 comes with rubber end pieces that people seem to say are lots better than the cork ones, so I got myself one of those even though I'm carbruleted. Supposedly you're supposed to lightly oil the rubber bits before installing. This set was just $10 at Vatozone, making it possibly the cheapest set locally available, but it includes 302 end pieces only. I didn't successfully turn up a set containing rubber 351 end pieces, but I just remembered that I didn't try searching for one for '90s 351 pickups like the Lightning.

Others say to set aside the normal Ultra Black AND pitch the end pieces, and get some special hard-setting stuff from Permatex called "Right Stuff", and use a 1/4" or so bead of that instead of the end gaskets. And of course, there are those who report success coating their cork end seals with Ultra Black. Obviously, with sealant, you need to make sure both mating surfaces are clean, clean, clean (I like to wipe stuff with lacquer thinner to make sure).


An interesting tip I came across is that even if you're using bolts instead of studs on your intake (and get real, stud sets are expensive!), you should get some allthread and rig temporary studs to guide the manifold straight down, thereby reducing your chosen end seals' tendency to smear or squirm. One-piece rubber oilpan gaskets come with little plastic clippy studs that serve this purpose, holding the gasket nicely in place while you fumble with the pan.


I'd mention to always use a dab of your favorite ordinary automotive RTV where the gaskets meet if using cork or rubber end seals, but you presumably know that.

[mrltd]

depends on the type of gasket. If it's the cork ones I toss them and use a bead of rtv. If it's the nice rubber, I use the rubber gasket and the dabs of rtv on the ends like the instructions say.

[86VickyLX]

depends on the type of gasket. If it's the cork ones I toss them and use a bead of rtv. If it's the nice rubber, I use the rubber gasket and the dabs of rtv on the ends like the instructions say.

This. Never had a problem with this method yet...

[86VickyLX]

An interesting tip I came across is that even if you're using bolts instead of studs on your intake (and get real, stud sets are expensive!), you should get some allthread and rig temporary studs to guide the manifold straight down, thereby reducing your chosen end seals' tendency to smear or squirm.

This is why I like Felpro gaskets, they have little connector things (can't think of the right word) that sit the gaskets on the head gaskets. Making that problem go away.
The felpro rubbers also conform to the place where they're supposed to be installed, in fact if I remember correctly, there's a guide hole for one of the end pieces in the block that pretty much puts it where it goes.

[1987cp]

Convenient. Didn't find any such guides in my intake-gasket kit, but it's easy enough to make some guides.

[1990LTD]

depends on the type of gasket. If it's the cork ones I toss them and use a bead of rtv. If it's the nice rubber, I use the rubber gasket and the dabs of rtv on the ends like the instructions say.

I will do this. I have had nothing but bad luck with cork gaskets thusfar....I'm sure they work okay for some folks, I just don't want anything to do with them.


When I tear into it, I'll use rubber felpro gaskets.

[gadget73]

the cork chinawall gaskets suck on every vehicle I've ever seen them used on. GM finally gave up on them for their V8 motors. If you buy a GM intake gasket, its 2 manifold to head gaskets and a tube of RTV for the ends.

[PushnFords]

depends on the type of gasket. If it's the cork ones I toss them and use a bead of rtv. If it's the nice rubber, I use the rubber gasket and the dabs of rtv on the ends like the instructions say.

+1

What I don't like is that regular RTV will eventually soften with exposure to oil and start to leak out. That Permatex Right Stuff holds up better but is expensive...and it is very strong so it can be a PITA to disassemble. If I use cork I glue the strips to the block with high tack and then put some more on the top...wait until it is good and tacky before you set the intake on or they can slide out. If you do use a bead of RTV make sure you get enough in there...but not too much that some of it squeezes inside and gunks up your engine. Years ago I didn't get quite enough in one spot and had a leak.

[1987cp]

Hm, Gaskacinch or similar probably makes pretty good sense, especially since you'll be putting some on the gaskets themselves anyway.

[Piece-it pete]

So, just to be clear to a schmoe like me, you put down a bead of RTV where ever the gasket would be?

Pete

[1987cp]

To make it clear to a schmoe like you, there are various options depending on how you choose to do it.

The three options I like best at this point would be:

- "Right Stuff" instead of end seals
- Cork end seals with Gaskacinch
- Rubber end seals, lightly oiled

[Piece-it pete]

Thanks.

And I've achieved official schmoedom! I'll have to go celebrate, get schnackered

Pete

[1987cp]

Meh, I still suspect I've got you beat in schmoedom. I'm really, really good at it! :banana: