V12 intake manifold gasket question. (324050)

Getting my intake manifold back on my car tomorrow and just noticed there are 2 distict sides to this gasket. Having a brain fart really about which way points up.

One side has a slight bulbous or convex pitch around each air inlet. Which I believe goes up against the manifold. While the other side has a distinct flatter/concave surface around the ports and would assume points down. Can someone confirm I'm correct or wrongly just overthinking this.

Bulbous side
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Flat side
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It probably doesn't matter. When your car was originally constructed, Ferrari used flat paper gaskets with silicone beads around each intake port. These would get sucked into the port over time causing vacuum leaks. They were superseded by the metal reinforced gaskets that you are now using, with no technical update about how they are to be installed.

I always install them with the concave surface facing the cylinder head, as that is what seems to make sense. The cylinder head intake gasket surface is probably flatter than the intake manifold, so I put the flatter surface of the gasket against it. Same goes for exhaust gaskets with raised beads.

 

I like to use gasket cinch on intake gaskets (this isn't specific to Ferrari, but just engine building in general) if I'm not planning on opening things back up any time soon. If any water passages are involved, then Ultra Black RTV around that area. Sometimes I just go with a super thin coat of Ultra black on the entire gasket, but not sure that would be a good idea (or necessary) in your case here.

Ray

 

Silicone sealant is always a poor choice for an intake gasket. It does not survive gasoline exposure. Neither do nearly every other gasket sealant compound, its just a slower process. Usually a good way to create vacuum leaks.

In general the best rule of thumb is if the manufacturer used no sealant, use no sealant.

As far as the specific gasket, Brian is right. Makes no difference. He like I dislike random assembly methodology so choose a method and stick to it. Every timing belt I install has the writing in the same direction for the same reason. It pleases my sense of order.

 

It's hard to tell from the photos but the curvature on this gasket may just be an artifact of the stamping process used to cut them out from sheet stock, and not intended to have any functional purpose.

 

Thanks everyone for the input. I got them and the manifold back installed today. I went with the round side up and installed them both dry, as that's how the old one came off my car. I appreciate everyone's perspective.
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Sealant on a vintage low tolerance engine has its place. I did use some Hilomar on the baseplate of a stuborn weber. The bakelite that is used to insulate the carb from the engine heat, does expand at a different rate, and I just don't want to torque the carb like a maniac.

No point in using such band-aid on modern cars. This being said, if this gasket is just the same quality as the so-called "pattern" gasket, I would definitively use some sealant. These are much cheaper but your mileage may vary.

Can't argue with that: it's what tinkering on a Ferrari is all about...

 

+1

I definitely agree with that statement.

In my particular case (where I opted to use a tiny bit of Ultra Black on part of the gasket to seal near a water passage), I had previously attempted the installation dry and it failed. I believe this was due in part to changes over the years among manufacturers with regard to the intake gasket material being used.

Ray

 

Hilomar is not affected by gasoline. I use it on the end fittings of the vintage yellow fuel lines. It makes for a very leak-proof assembly. They now make a spray can for use on gaskets.

 

Mine are very leak proof without Hylomar. Hylomar, the favored sealant used by builders of the worlds leakiest cars.

 

Mine is a belt and suspenders approach