INTAKE MANIFOLD QUESTION. Options

[JOE M]

I just removed my intakes and old carbs. I found that there was a spacer between the manifolds and block that is apx. 1/2" thick. It is made out of some type of material that is similar to carbon fiber. Im not sure exactly what it is but 1 of the spacers is broke. Is this part needed or was the P.O doing something funny. There are 2 spacers 1 per side.

[dbgriffith75]

I'm not sure why there'd be 2 per side... the PO must've been doing something screwy because there should only be one gasket (spacer) per side. Well, technically 3- the thick gasket should have 2 thin ones on either side of it... or so Rich would have us believe. (IMG:style_emoticons/default/biggrin.gif)

[BarberDave]

(IMG:style_emoticons/default/smilie_pokal.gif)

Thick casket sandwiched between 2 thin ones, the thin act as a seal between the

head thick 1, and likewise for the other with the manofold. The thick one ,

( has a name i can't pronouce ) it's just a insulator . I keeps the heat from the

block from progressing up to the carbs and thus the gas.

Dave (IMG:style_emoticons/default/slap.gif)

[SLITS]

Single setup .... it's a Bakelite Insulator with two paper gaskets glued to it. Paper forms the seal ... Bakelite is the insulator..

[SirAndy]

Stock FI gaskets. You should be able to get them from all the usual parts suppliers ...
(IMG:style_emoticons/default/bye1.gif) Andy

[maf914]

When using dual Webbers should the FI insulators be used at the base of the manifolds or not? Reduce heat transfer to the manifolds or let the manifolds heat up to promote fuel atomization?

I have used the insulators with carbs but I was never sure about it. (IMG:style_emoticons/default/idea.gif)

[SirAndy]

let the manifolds heat up to promote fuel atomization?

Sounds good in theory, but that's not how it works. Carbs suck huge amounts of air through a small opening, thus dissipating a lot of heat.
Ever heard of carbs "icing" up?

Go for a spirited run and immediately get out and touch your carbs. They'll be very cold. The same principle is used in refrigerators to cool down the air inside.


What the thick FI gaskets do is help preventing heat soak when the car idles or after you shut it off.
A hot motor will heat up the manifolds and carbs after shutoff and can boil the gas in the float bowls. The carb version of "vapor lock".

While you're running the car hard, they make no difference. But they insulate the runners from the heads, minimizing heat transfer at idle or after a run.
(IMG:style_emoticons/default/shades.gif) Andy

[r_towle]

You need the phenolic spacer for exactly what Andy says.
They did not have them on the early 356's and they commonly suffer from boiling fuel and a form of vapor lock.

Joe, if you need one, I have probably have a spacer or two around here.
Dont use a broken one.
Its basically thick formica (paper and resin mixed) and can be repaired with epoxy of contact cement,,,depending upon what is going on.
You dont need an air leak...
Either come over here and get another one, or fix the one you have so its perfectly leak free.

I am around tommorow.
Rich

[dbgriffith75]

let the manifolds heat up to promote fuel atomization?

Sounds good in theory, but that's not how it works. Carbs suck huge amounts of air through a small opening, thus dissipating a lot of heat.
Ever heard of carbs "icing" up?

Go for a spirited run and immediately get out and touch your carbs. They'll be very cold. The same principle is used in refrigerators to cool down the air inside.


What the thick FI gaskets do is help preventing heat soak when the car idles or after you shut it off.
A hot motor will heat up the manifolds and carbs after shutoff and can boil the gas in the float bowls. The carb version of "vapor lock".

While you're running the car hard, they make no difference. But they insulate the runners from the heads, minimizing heat transfer at idle or after a run.
(IMG:style_emoticons/default/shades.gif) Andy

What if a guy was to lose the spacer between the intake and head and place one between the carb and the intake? It would probably have to be a thicker one but it would still do the job of preventing the gas from boiling in the carb, which would then, theoretically, allow the gas to atomize in the manifold, right?

I only ask because this is how the carbs are mounted on some older American cars and pickups. The intakes are bolted directly to the heads and then a thick (some as thick as 1/2") spacer/gasket is placed between the intake and carb. I don't know if engineers back then planned to atomize the gas in the intake, but the spacer was there to prevent the carbs from overheating after shut off and causing vapor lock.

[r_towle]

let the manifolds heat up to promote fuel atomization?

Sounds good in theory, but that's not how it works. Carbs suck huge amounts of air through a small opening, thus dissipating a lot of heat.
Ever heard of carbs "icing" up?

Go for a spirited run and immediately get out and touch your carbs. They'll be very cold. The same principle is used in refrigerators to cool down the air inside.


What the thick FI gaskets do is help preventing heat soak when the car idles or after you shut it off.
A hot motor will heat up the manifolds and carbs after shutoff and can boil the gas in the float bowls. The carb version of "vapor lock".

While you're running the car hard, they make no difference. But they insulate the runners from the heads, minimizing heat transfer at idle or after a run.
(IMG:style_emoticons/default/shades.gif) Andy

What if a guy was to lose the spacer between the intake and head and place one between the carb and the intake? It would probably have to be a thicker one but it would still do the job of preventing the gas from boiling in the carb, which would then, theoretically, allow the gas to atomize in the manifold, right?

I only ask because this is how the carbs are mounted on some older American cars and pickups. The intakes are bolted directly to the heads and then a thick (some as thick as 1/2") spacer/gasket is placed between the intake and carb. I don't know if engineers back then planned to atomize the gas in the intake, but the spacer was there to prevent the carbs from overheating after shut off and causing vapor lock.

Try it and let us know.
There are spacers for webers out there...they mount them on v8 hotrods all the time...so that spacer you are talking about is an off the shelf part.

Might make it run better...hmmm

Rich

[dbgriffith75]

Try it and let us know.
There are spacers for webers out there...they mount them on v8 hotrods all the time...so that spacer you are talking about is an off the shelf part.

Might make it run better...hmmm

Rich

I'd love to Rich but I don't have a teener in working condition to test it out on. (IMG:style_emoticons/default/dry.gif)

[JOE M]

I fixed the one that was cracked. I still do not have my intakes so I cant do much yet.