Insulation under intake manifold

[live4theking]

So, I'm pulling the heads to remove the broken exhaust manifold studs. Under the intake was a piece of foil faced insulation. It was pretty heavy feeling with some kind of fluid. I would like to replace it.

What should I use?

Thanks for any suggestions.

 

[Zymurgy]

The fluid shouldn't be in there, just straight insulation wrapped in aluminum. Not available from too many sources, I will try to find where I bought it from. You could probably make your own, nothing to special.

Found it this is where I bought it from.

Big Block Intake Manifold Insulation Dodge Plymouth Mopar

 

[Carmine]

It's just there to deaden tappet noise. I wouldn't bother to replace it if the old stuff is messed up.

 

[Zymurgy]

I figure it doesn't hurt to insulate from some of the heat. My gas never boils from my carb, and I know other have that problem. Cheap and factory correct (you can see it), dissipate some heat from the engine can't hurt.

 

[1978 NYB]

Toss it. Not needed.

 

[Big_John]

You don't really need it, but it is there to make the lifter area quieter. It doesn't do anything to keep the intake cooler as the exhaust crossover is in the intake and above the insulator.

Replace it if you want. Your call.

 

[OneEyed]

We just had this whole discussion over here, you'll even find a link where to buy it.
Stock 383 2 bbl to 4 bbl swap.

 

[live4theking]

Thanks for the input everyone. I added some insulation to my attic a few years that didn't have any paper on it. I bet I can find some of that and cover it in foil and make it work. I'm not concerned about it being 100% correct.

 

[Polara_500]

I've done that several times in the past.

 

[rexus31]

Thanks for the input everyone. I added some insulation to my attic a few years that didn't have any paper on it. I bet I can find some of that and cover it in foil and make it work. I'm not concerned about it being 100% correct.

Be sure and use heavy duty foil. Reynolds Wrap won't cut it.

 

[live4theking]

Thanks

 

[73Coupe]

At first I though the insulation was to keep the valley pan cooler, and to prevent burnt oil from collecting on the underside of it (from manifold crossover heat). But then I found out about the noise reduction reason. I did not replace my insulation, and I like the sound of the motor better. It's more "throaty" sounding, perhaps due to resonance or something. I don't hear tappets except upon startup. Plus it makes cleaning the motor easier.

 

[stubs300]

I've had no problems with using Reynold's wrap when I did mine, and that was over 20 years ago and it's still going strong. I used the pink insulation with paper on it with no problems. Good Luck

 

[CBODY67]

The reason I read for that insulation being there was not noise, but to keep the valley pan gasket from stress-cracking with time and age. Of course, Chrysler had a part number for it!

Not really "insulation" as it doesn't really insulate anything, but more of a vibration damper from putting a little pressure on the valley pan to change its resonant frequency. The foil keeps things "clean and neat", compared to just having a piece of bare yellow fiberglass under there.

It might keep the crossover passage heat more in the manifold than add to the heat load under the hood? In so doing, it might help divorced choke performance in cooler weather, plus better fuel distribution from a warmer "hot spot" in the plenum?

Some other engine designs, which use a metal bolt-in plate rather than the valley pan gasket, there is no "insulator" under there. Other "race" manifolds for some motors are open in order to keep the manifold cooler.

Seems like some vendors have an aluminum valley cover for B/RB engines? Then there are different intake gaskets.

CBODY67