Intake manifold gasket replacement question

[Stephen Bowen]

Okay Campers. Same truck I seem to always be working on. 1989 Bronco II with a 2.9 V6

Doing the intake manifold and picked up the FelPro intake gasket kit for it. Of course the flippen thing is missing the handy ‘tech tips’ one-sheet that answers most of the questions.

So my question to the group:

The gasket is made out of a very interesting graphite and rubber composite attached to a thin thin and thin steel sheet with the cutouts. (aka, valley pan wannabee) The gasket has red “lines” for lack of a better word. I believe these are small trace lines of Silicone sealant for the ports and such. (can’t be 100% sure, the one sheet that explains this is gone)

My shop manual states clearly to apply a thin coating of sealant (most likely RTV black) on the ports on both sides. Then to apply, and torque down in 5 steps.

I did this 4+ years ago on the same truck, and can not remember what that one-sheet stated. Whether to apply the sealant..or do a dry install???

On the lighter side, the new gasket kit no longer comes with the tiny tube of RTV–FelPro went and glued a cork rubber gasket for the ends of the intake. (in the past you’d have to run a bead of RTV, let it do it’s thing..and then install the intake.)

So the question for tomorrow when I do this–and HOPEFULLY solve my coolant in the cylinder issue…

Install 100% dry after a full clean up of the mating surfaces.

Install using a very thin coating of sealant.

Install using the “Copper Gasket Sealant Spray” the local auto parts sells.

What would YOU do to ensure this won’t fail?

FEL-PRO Part # MS93771

That’s the gasket set. They never did update the photos. The cork rubber ends on the intake gasket replaces the RTV.

Any ideas or feedback? I feel like we should do a poll at this point.

Thanks!!

S-

(Yeah I should know this. All that training and being in a different field now seems to have melted what is left of my mind)

Topic

[Glenn]

Some of the Ford guys will weigh in, but after looking at pics of the gasket, this camper says 100% clean and dry. Of course it wouldn’t hurt one thing to put a little skim of black rtv on the cork potions for insurance. It shouldn’t degrade the cork. Best of luck.
..

[Joe]

I always use silicone on pretty much any gasket. There’s very few times where it’s a bad idea. Just don’t glob it on there but trace thin lines around the coolant valleys and other ports. Do this on both sides of the gasket. Get in touch with your inner baker.

I usually use “right stuff” silicone. Stuff could seal up your buttcrack if you use enough of it.

[Bill]

I would install the gaskets as they are. Throw the cork away and use RTV for the end seals.

[Glenn]

With all due respect to quickNpainless’ reply, I’ve only used black rtv to fill in minor surface imperfections caused by cavitation on an aluminum intake. Once, I used it too liberally. It actually acted as a lubricant as I torqued down the manifold. As a result, the gasket slipped out of place and I had to do the job over again. I wouldn’t use it. But if you decide to do so, use it’s sparingly.

[John Hugon]

wysetech stated:

Throw the cork away and use RTV for the end seals.

Yes… and I would use adhesive RTV

[Stephen Bowen]

Okay, the stinking thing is finished. Attached are two photos. The first one shows just how bad the coolant was backed up.

I found the one bolt next to the offending ‘leaker’ loose. Not sure how it could have worked itself free? But it did, and the gasket shows the damage from the clamping pressure not being equally displaced.

Had a major El Dumbo’ during install of the new gasket. Hope it won’t crap out. I went to torque it down, and this engine requires 5 steps total. I asked my wife for the first torque value and she mistakenly read off the ‘final’ torque of 18ftlbs. So I torqued that one on the same corner that failed to that spec….then asked for the correct pattern, when I noticed it starts off at 3, 6, 12, 18final, run engine for 15 minutes and re-torque.

So I made the one that I started with back to loose. And started all over again. Sense it was only the one bolt that got screwed up? I am hoping that the coating (light) of RTV Black on all the ports will help prevent the gasket from failing due to one bolt being not done as per instructions.

That just leaves the oil change on Tuesday and re-timing the engine. I dialed in that timing pretty darn close. Plus I checked the timing chain for slack. Nadda. Nice and steady movement, moved smoothly and no glitch when reversing direction slightly.

I’ll add more if needed. For the time being the engine ran pretty smooth (even with just vacuum timing)

Have a super day!!

S-

Attachments:

• Yuck.jpg
• blownoutgasket.jpg

[Bill]

I find that people over complicate gasket installation. If you needed sealer on gaskets then it wouldn’t have a gasket, only silicone. Fifty years ago we used gasket shellac because of poor gasket materials and machining. That’s not true today.

Silicone on intake gaskets degrades over time from gasoline and you end up with leaks.

[Stephen Bowen]

After fighting with that intake? Actually it wasn’t the intake that really Pi&&ed me off. Ford uses no retaining flange on the valve covers for a 2.9v6. So as you attempt to tighten the bolts to spec? The gasket slides either outside the flange…or sneaks into the valve cover. The flange is flat, where common sense would have a flat flange with an abutment to hold the gasket in place.

Anywho. The shop manual said to coat the gasket with sealer–and with the lack of the install ‘tips’ in the box? The light coating should at least help with the bolt that got incorrectly installed, and then correctly installed a moment later.

I didn’t go crazy with it. Just a thin amount like 1/2 the thickness of a credit card.

S-

[Author]

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