Editing Intake manifold

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==Overview==
The intake manifold is an important part of the induction system. Basically it connects the carburetor or throttle body to the intake ports of the cylinder head and in some cases like the small block and big block Chevy engine, it seals the lifter valley and provides a means of mounting the distributor and water neck.

But that is just the tip of the iceberg. The intake manifold design has a lot to do with how the engine will perform and an radically influence the shape of the power band. Matching the intake type to the engine and vehicle specs is an important part of making a balanced combination, and the choice of what intake best suits the circumstances should not be taken lightly.

==History==
Factory intakes have run the gambit from simple log intakes with no concern for efficiency or high flow, to aluminum high rise intakes designed for multiple carbs (tri power and dual 4 barrels).

There have been "oddities" like Ford using a Q-jet on the 429 Cobra Jet, seen below:

[[File:429 CJ Q JET INTAKE 2.jpg|thumb|left|300px|429 Ford factory Q-jet cast iron intake]] <br style="clear:both"/>

==Types of intakes==

===Dual Plane===

{|
|[[File:EDELBROCK PERFORMER INTAKE.jpg|thumb|335px|center|The Edelbrock Performer- one of, if not THE most popular intakes of all time. Arrow indicates PB vacuum port]] 
|[[File:327-350HP SQUAREBORE OEM INTAKE.jpg|thumb|320px|center|327 ci/350 HP OEM aluminum squarebore intake]]
|}
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===High rise===
[[File:Stealth 8016.jpg|thumb|right|400px|Original Stealth p/n 8016 intake]]
As of 2012 the Edelbrock Performer RPM/RPM Air-Gap intake manifold is considered to be the best of the breed. It consistently makes as good if not better power over a wider range than any of it's competitors. In fact, it rivals the open plenum intakes like the Edelbrock Vic/Vic Jr.- even at the top of the powerband, unless the cam and cylinder head intake volume are up there pretty good. It will always make more bottom end than the open plenum intakes but that is to be expected. But what is surprising is how well the RPM performs at the top of the power band.

The original Weiand Stealth p/n 8016, which has been discontinued and replaced by p/n 8150, is considered by some who are "in the know" to be an equal to the Edelbrock RPM.

The original Holley p/n 300-36 was possibly the best of breed in its day, and it isn't made any longer either. The replacement Holley p/n 300-36S is NOT the same manifold.

The Edelbrock RPM 7101, Weiand Stealth 8016 and Holley Street Dominator 300-36 were all patterned after the dual plane, high rise intake first used on the Z-28 and LT-1 in the late '60s and early '70s. Those original aluminum Chevy manifolds were cast by the Winters Foundry and will have the Winters "snowflake" cast into the aluminum.

[[File:CB3 003.jpg|thumb|400px|left|The Edelbrock C3B was originally designed for the Holley 3-barrel carb (note the plenum notch to clear the secondary throttle plate of the Holley 3-barrel). Still a decent intake for a mid-sized SBC. HEI will usually just barely clear, may need slight clearancing]]
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[[File:Typhoon 52021.jpg|thumb|300px|Typhoon p/n 52021]]
Professional Products makes a manifold of this design also, called the Typhoon, p/n 52021 for satin finish. The Power+Plus Typhoon Manifold is a high performance dual plane, 180° street manifold designed to be used with Holley, Carter AFB, or Edelbrock square bore carbs. For street applications use 600-700 cfm vacuum secondary carbs. For high performance street, use 700- 800 cfm double pumper carburetors. This manifold produces power comparable to some single plane manifolds yet retains the throttle response and drive ability typical of a dual plane. This manifold also features cast-in nitrous bosses with water outlets at all four corners plus dual distributor holddowns. This manifold is .70-inches taller than the PP-52000 or PP-52001. It has a provision to add an oil fill tube. No provision for exhaust heated or stock style chokes. Accepts late model waterneck, A/C, alternator, and HEI. Will fit cast iron bow tie heads and ‘87-’95 cast iron or aluminum heads. Will not fit under a stock Vette hood. This product can be found at <a href="https://performanceinjection.com/index.php?c=0&p=369">www.performanceinjection.com</a>

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===Air gap===
[[File:Rpm 7501 air-gap.jpg|thumb|400px|left|Edelbrock SBC RPM Air-Gap intake. Air can circulate beneath the plenum; plenum is separated from the hot motor oil being splashed onto the bottom of the intake where it seals the lifter valley.]]
The so-called "air gap" intake concept has been around since the late '40s-early '50s. It has been used by various auto makers through the years, like Pontiac, as original equipment. Air can circulate beneath the plenum; the plenum is separated from the hot motor oil being splashed onto the bottom of the intake where it seals the lifter valley. 

Only because the Chevy V8 uses the intake bottom to seal the lifter valley is this considered to be an improvement. Other engine that use a separate plate to cover the lifter valley have had "air gap" intakes all along. But with the SBC engine, especially if using Vortec or aftermarket heads that lack a heat crossover beneath the plenum, the engine may tend to be cold-blooded until the intake comes up to temperature from engine heat.

That means the Edelbrock Air-Gap intake will require a longer warm-up. In cold weather this can lead to driveability problems, almost like a tunnel ram. The air/fuel mixture- if tuned for a fully warmed up engine- will be lean until the engine is up to temp. This can be compensated for by the choke, but if using the choke, spirited driving is out until the choke is fully open.
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===Single plane===
{|
|[[File:WEIAND 7546 001.jpg|thumb|450px|center|Weiand single plane p/n 7546.]] 
|[[File:Sm int.jpg|thumb|450px|center|Edelbrock Streetmaster intake, a predecessor to the Torker. Was made in several versions]]
|}

==Multiple carb intakes==

===Dual 4 barrel===

===Tri power===
[[File:Tripower.jpg|thumb|300px|left|Pontiac Tri Power]]
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==Ram induction==

[[File:H&M Enginex7.jpg|thumb|left|330px|'''High and Mighty''' 
One of the earliest versions of ram induction]] <br style="clear:both"/> 

===Cross ram===
[[File:X-ram comparison.jpg]]  
==Individual runner==

{|
|[[File:Ls7 xram.jpg|thumb|300px|center|LS7 IR cross ram]]
|[[File:Ls x ram ir.jpg|thumb|300px|center|LS Chevy with Holley cross ram set-up]]
|}

==Tunnel ram==
One of the more iconic intake set-ups is the tunnel ram. First used in competition in drag racing, it was made a household word by driver/engine builder/tuners like Grumpy Jenkins (RIP). He used a 331 SBC with a tunnel ram/dual Holley 4 barrel carbs against engines ~100 ci larger than his in A/Stock- and won.

===Cross ram===

[[File:1960 Dodge D-500 Long Ram Engine.gif|left]][[File:413 300 SERIES CHRYSLER CROSS RAM ENGINE.jpg|frame|right|413 Cross Ram]]<br style="clear:both"/> 

==Carb adaptors==
Adaptors have been used since the beginning. There are adaptors to mount dual carbs to a single carb intake, to mount 4 barrel carbs to 2 barrel intakes and vice versa, there are adaptors to mount a squarebore carb on a spreadbore intake and vice versa, there are adaptors to mount a squarebore carb on a Dominator intake, etc.

One of the more useful adaptors (if it can be called that; Edelbrock does) is the Edelbrock p/n 2732. It is a simple flat steel plate and a pair of gaskets used to prevent vacuum leaks at the secondary side of the intake when mounting a squarebore carb onto an intake having a carb flange designed to accept ''either'' a squarebore or spreadbore carb.

{|
|[[File:Edel pn 2732 carb plate.jpg|thumb|200px|Edelbrock p/n 2732 carb plate for squarebore intake flange]] 
|[[File:Carb base gasket 4150-4160 vs 4500-1.jpg|thumb|250px|left|Difference between squarebore and Dominator carb base]]
|}
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==Carb spacers==
Carb spacers in their various designs are often used as a tuning aid and for helping to make power in the range where it's needed.

===Open spacer===
Tend to boost output in the upper range and will increase plenum volume. On an intake like the Edelbrock RPM (non Air Gap) dual plane intake, using an open 1" spacer will let the intake make identical power to the cut down plenum divider of the Air Gap.

===Divided spacer===
These will retain the dual plenum low-to-midrange benefits while possibly raising the power peak. Tends to make the runners seem longer.
 
[[File:CARB SPACERS WOOD Q-JET 001.jpg|thumb|300px|left|Pair of homemade spacers.]]
[[File:CARB SPACERS WOOD Q-JET single.jpg|thumb|300px|left|Spacer made specifically to fit the Pontiac Performer intake. Spacer is upside down.]] 
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===Also see:===
*[http://www.hotrodders.com/forum/carb-spacer-163755.html Carb spacer] thread on Hotrodders forum.
*[http://cms.nhra.com/dragster/1999/issue05/racing_technology.html Racing Technology Tuning with carburetor spacers] from NHRA.com

==Marine intakes==
[[File:VORTEC ALUM INTAKE VOLVO PN 3856270.jpg|thumb|300px|left|Volvo Penta p/n 3856270 marine intake with brass water crossover/thermostat port.]]
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==Vacuum ports/fittings==
[[File:VACUUM TAPS OEM 001.jpg|thumb|300px|left|OEM vacuum taps]]
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==Fasteners==
L30/L31 Vortec engines use fasteners made specifically for the plastic Vortec intake and intake gasket. To prevent over torquing the fasteners and crushing the intake gaskets, the bolts come with a longer shank having a non threaded bottom portion so as to bottom out before the gasket or intake sealing flange/bolt hole is compromised. Below the OEM bolt is on the left, an ARP bolt, right:

[[File:VORTEC INTAKE BOLTS.jpg|thumb|left|]] <br style="clear:both"/>

==Gaskets==

[[File:8017 Intake Gasket VORTEC BO LAWS.jpg|thumb|300px|left|Dual pattern intake gasket; Vortec and Gen I SBC]]
[[File:VORTEC GASKET OVER STANDARD INTAKE GASKET.jpg|thumb|200px|left|Vortec intake gasket over Gen I gasket]]
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==Intake installation==
Generally speaking, using RTV on intake gaskets acts as a lubricant until it's set up; using it alone can let the gaskets slip out of position when tightened. Most gasket makers caution against using RTV, especially on the side of the gasket that has an RTV bead applied at the time of manufacture. Instead of using RTV over the entire gasket surface, use [http://3mcollision.com/3m-super-weatherstrip-and-gasket-adhesive-08002-yellow.html 3-M weatherstripping cement] or [http://www.summitracing.com/parts/EDL-9300/ Gasgacinch] on one side of the gasket to hold the gasket in place. These are able to hold a gasket in position almost immediately if applied by the directions. Nothing is needed on the other side in most cases, although a light application of RTV (following the directions for skim time) or one of the non-hardening sealers mentioned above can be used around the water crossovers on ''both'' sides of the gaskets, in conjunction with the cement. 

Some prefer to use [http://www.permatex.com/products/automotive/automotive_gasketing/gasket_sealants/Permatex_Super_300_Form-A-Gasket_Sealant.htm Permatex 300] or [http://www.permatex.com/products/Automotive/automotive_gasketing/gasket_sealants/auto_Permatex_Aviation_Form-A-Gasket_No_3_Sealant_a.htm Permatex Aviation] non-hardening sealers.

{{Note1}} A couple cut off bolts or studs can be used to position the gasket perfectly, remove before installing the intake.

RTV should be used on the ends of a Chevy intake instead of the cork or rubber seals supplied with many gasket sets. Apply a 1/4" thick bead of RTV across the seal surface at each end of the block. If using an O2 sensor be sure to use sensor safe RTV.

==Intake heat shield==
Many OE intake manifolds came equipped with a sheet metal heat shield. The purpose of the heat shield is to protect the bottom of the intake manifold from hot oil being splashed up onto it. This wasn't to keep the intake cooler, it was to keep the splashed oil from carbonizing on the hot exhaust heat crossover that runs beneath the plenum to provide carb heat.

That said, if the heat crossover has been blocked off, the shield would tend to help keep the hot oil off the intake. But after the engine has heat soaked, the underside of the intake will be close to the temperature of the rest of the engine, anyway.

===Removing the heat shield===
During use, the heat shield can become occluded with built up carbon. This can be cleaned out by removing the heat shield.

Use a sharp, gradually tapered 1/4" chisel to get up under the edges of the rivets (you might need to grind a chisel down to get the best tip. Don't grind until red hot or the temper will be lost). The rivets used on Chevy intakes usually have spiral ridges on them that help hold them in position, so they tend to turn as they come out.

If a rivet gets broken off in the removal process, do not worry. Leave the broken piece in the intake. Move a little to one side of the hole where the broken rivet is located and center punch and drill a new hole through the heat shield into the intake to receive a replacement rivet. A depth stop can be used to prevent the hole from being drilled too deep. 

===Replacing the heat shield===
The shield should be replaced after cleaning. The intake can be tapped for screws or the rivet holes peened/staked to close them some so the rivets will have a good hold. The original rivets may be OK to be reused if they weren't damaged during removal, or new rivets can be bought to replace them. When replacing the rivets use locktite to help hold them in place. 

[[File:Heat shield rivets.jpg]] <br style="clear:both"/>

==References==

{{Develop1}} 
[[Category:Engine]]
[[Category:Carburetors]]
[[Category:undeveloped articles]]