How to install a cowl induction system on a 70-72 Chevelle or El Camino - El Camino Central Forum : Chevrolet El Camino Forums
El Camino Central Forum : Chevrolet El Camino Forums
 
Ground Up
User Name
Password
Go Back   El Camino Central Forum : Chevrolet El Camino Forums > Body & Chassis > Body Restoration

Reply
 
Thread Tools Display Modes
  #1  
Old 01-13-2010, 10:02 AM
rushgator's Avatar
rushgator rushgator is offline
Director, Region 13 Texas



Master Wrench
 
Join Date: Apr 2004
Name: Glenn
Location: Honey Grove, TX pop. 1,976
Year: 1972
Model: El Camino
Region: 13(TX)
NECOA #: 2834
Posts: 4,950
rushgator is just really nice
Default How to install a cowl induction system on a 70-72 Chevelle or El Camino

Just found a good article on OPGI's website that gives detailed instructions on installing a cowl induction system on any 70-72 Chevelle/El Camino:

Part 1


How to install a cowl induction system

Does a working cowl induction system add more horsepower to your Chevelle? Actually, no. But it sure looks awesome, and it’s doesn’t require years of wrenching experience to install.


Whether your car was originally cowl induction equipped or not, we’ll show you how to install the complete system. In a few hours, with some basic tools, you’ll be flashing warning signs to all the other muscle on the street.

All of the parts we’ll need are available from Original Parts Group: hood, cowl induction door assembly, hood screen, air cleaner spacer, cowl induction air cleaner assembly, a/c intake relay, a/c wing nut, vacuum actuator, vacuum actuator support, c/i wiring harness, firewall grommet, valve frame kit, air control switch and bracket, flow control valve, hood pins (if desired).

Tip: Whether you’re using your existing cowl equipped hood or a brand new one, you should remove the hood from the car and place it upside down on a firm level surface, at least a foot off the ground. You can install the system with the hood still attached, but it’s much easier when removed. Hood removal is very simple, and you will need two people to do it. Unscrew the 4 bolts that retain the hood to its hinges, and carefully lift.

First, a few words of advice and precautions:

• A cowl induction system can be installed on any ’70-’72 Chevelle that is equipped with a four-barrel carburetor. This includes the following engines: 350, 396 and 454.
• You’ll want to prime and paint your hood before installing the cowl system. Be sure to paint the cowl door and screen body color.
• Be very careful working around the underside of the hood. It is stamped sheet metal, and all the edges are very sharp!
• When reinstalling the hood, make sure you line it up correctly on its hinges. This is done by lightly tightening the bolts, then gently shutting the hood to check for fit. Once you’re satisfied, tighten all 4 bolts with a socket wrench.

In our first step, we’ve inserted the valve frame cage flap into the valve frame cage using the 3 supplied retaining clips. We’ve also inserted the electric solenoid into its pre-attached retaining bracket. All the parts necessary for this step are included in OPGI’s “complete valve frame setup”.

With the cowl induction hood placed upside down on a firm surface and raised off the ground, insert the assembled valve frame setup into the hood opening. Secure with the 6 supplied self-tapping screws using a 5/16” socket wrench.
__________________

To view links or images in signatures your post count must be 0 or greater. You currently have 0 signatures.


Freedom. Liberty. Speed.

"Wind-In my hair-Shifting and drifting-Mechanical music-Adrenalin surge"--Rush, Red Barchetta
Reply With Quote
Sponsored Links
Advertisement
 
  #2  
Old 01-13-2010, 10:03 AM
rushgator's Avatar
rushgator rushgator is offline
Director, Region 13 Texas



Master Wrench
 
Join Date: Apr 2004
Name: Glenn
Location: Honey Grove, TX pop. 1,976
Year: 1972
Model: El Camino
Region: 13(TX)
NECOA #: 2834
Posts: 4,950
rushgator is just really nice
Default

Part 2

Next, we insert the firewall grommet into the pre-stamped hole in the hood, and feed the tan colored wire from the wiring harness through the grommet. Then, attach the tan colored wire terminal to the solenoid. You will access the solenoid through the large air cleaner hole in the center of the hood.

Now we will assemble the hood door. Attach the 2 door supports (one at each side of the hood door) using the supplied bushings and pivot screws. The cowl induction hood door assembly kit is available from OPGI. Even with the screws fully tightened, the door supports will feel loose and not really firmly connected to the hood door. This is normal, as the hood door must be allowed to open and close freely.

Now that the hood door is assembled, we’re going to install it into the hood. Lay the hood door into the pre-stamped hole in the hood, and attach it by screwing 4 (2 each side) 3/8” self tapping bolts through the hood door supports. NOTE: due to irregularities in metal stampings, you will need to shim the door supports (using washers) in order to properly align the hood door. Look under the hood (actually, on top of the hood) and make sure that you shim the door so that it sits flush with the hood surface!

Before you finally tighten down those door supports, make sure the hood door is able to open and shut freely! There should be at least 1/16” of clearance between the door and the actual hood. Don’t forget to take into consideration the thickness of new paint!

Next, insert the vacuum actuator into the vacuum actuator support and fasten to the hood using 4 1/4” self-tapping bolts. Then, attach the vacuum actuator “throw” to the cowl hood door using the supplied screw.

Now that we’ve got all the hood hardware in place, we’re going to attach the cowl hood screen to the rear of the hood opening using 8 self-tapping screws. This will keep out those pesky leaves and unusually large bugs!

Because there’s no vacuum in the system yet, the door will remain in its open position.

You may be wondering why your ’70-’72 A-body has three big gaping holes in the cowl grille area (just below the windshield). Well, they’re obviously for air flow, but for some strange reason the factory left them open and unprotected. To keep out leaves and other extraneous junk, you may want to invest in a set of cowl grill inserts (also available from Original Parts Group). They simply snap into place.
Reply With Quote
  #3  
Old 01-13-2010, 10:04 AM
rushgator's Avatar
rushgator rushgator is offline
Director, Region 13 Texas



Master Wrench
 
Join Date: Apr 2004
Name: Glenn
Location: Honey Grove, TX pop. 1,976
Year: 1972
Model: El Camino
Region: 13(TX)
NECOA #: 2834
Posts: 4,950
rushgator is just really nice
Default

Part 3

The entire hood should be reattached to the car at this point. Have a friend help, and take your time to make sure both sides of the hood align properly with the fenders.

Now we’re going to get the whole system activated. If wire routing and switch installation intimidate you, you’re in for a treat here. This is a pretty simple set-up. Just follow along.

Attach the air cleaner intake valve relay assembly to the firewall using a #10 self-tapping screw. This unit sends a “hot” signal from the wiring harness to the cowl induction solenoid.

There’s a black colored “plug” located in the firewall just behind the engine’s valve cover. Pop it open and insert the pink and brown colored leads from the wiring harness, as well as the braided section of wire. The pink and brown leads will feed down and attach to the air control valve solenoid switch, which we will install at the gas pedal. The braided section of the wiring harness will also feed down and attach to the car’s existing wiring harness. At the gas pedal, you will need to remove the existing retaining plate.

Attach the air control valve solenoid switch to its bracket using the supplied screw. Now fit the bracket to the existing holes where you removed the retaining plate before. The protruding post on the side of the solenoid switch will press against the gas pedal linkage upon full throttle acceleration, actuating the vacuum and opening the cowl hood door.

Attach the pink and brown wire leads to the terminals on the solenoid switch (the fitting shape will be obvious), and attach the braided section to the existing wiring harness under your dash. This last connection will provide power to the entire cowl induction system.

Back in the engine compartment, plug the 2 remaining short wires into the air cleaner intake valve relay assembly (again, the fitting shape will be obvious). Now route the tan colored wire (that attaches to the electric solenoid we installed at the beginning of this project) through the wiring sheath on the firewall to protect it.

You’ll need to place the cowl induction spacer assembly on top of the carburetor. This ring simply sits atop of the carb, and allows the air cleaner to sit up a little higher, into the cowl hood.

Attach the cowl induction air cleaner flange and seal kit (part#KC1500 black lid) or (part#KC1501 chrome lid).

Now you’ll have to fit a 1/4” rubber hose (not included in kit, but available from any auto parts supply store) to the vacuum actuator. Then route the hose to fit the other end to the vacuum port located on the intake manifold just behind the carburetor. The vacuum port is standard on all Chevelles, as it is used for other vacuum operated accessories.

Fire it up and grab a few shifts. Watching that cowl door open under full throttle makes it all worthwhile!
Reply With Quote
  #4  
Old 01-13-2010, 01:15 PM
Tuggy24g
Guest
 
Posts: n/a
Default

Great info you found!
Reply With Quote
  #5  
Old 12-31-2010, 08:03 AM
slingslingbinks's Avatar
slingslingbinks slingslingbinks is offline
Senior Member

Master Wrench
 
Join Date: Dec 2010
Name: Scott
Year: 1970
Model: El Camino SS
Region: 16(CO,MT,WY,UT)
NECOA #: 18090
Posts: 218
slingslingbinks has a spectacular aura about
Default

I found that i had to disconnect the vac. hose to my hood. I was doing too many w. o. t.'s to watch the flap open and couln't afford the gas.
Reply With Quote
  #6  
Old 12-31-2010, 08:28 AM
CANTED's Avatar
CANTED CANTED is offline
Deputy Director Region 7 (TN-AL-GA)

Master Wrench
 
Join Date: Feb 2006
Name: Jim
Location: Rock Spring, GA
Year: 1970
Model: El Camino
Region: 7 (AL,GA,TN)
NECOA #: 6858
Posts: 2,775
CANTED is a jewel in the rough
Garage
Default

I'm not so sure I agree with OPGI's first line. There are benefits from breathing air from the cowl area, be it a low pressure area or just cooler denser air, or both. This versus breathing hot under hood air, don't take a rocket surgen to figure out. I have the inner door open all the time and the air cleaner snorkel taped over so it always breathes from the cowl. If, however they are talking about a benefit when the outer door opens, then I would agree. That is just cool factor.
__________________
Jim
70 ElCamino 461 solid M20 331eaton
Third gen gallery, page 12
Reply With Quote
Sponsored Links
Advertisement
 
Reply


Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)
 
Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump

All times are GMT -7. The time now is 11:23 AM.
Powered by vBulletin® Version 3.8.7
Copyright ©2000 - 2014, vBulletin Solutions, Inc.
Logos and trademarks on this site are property of their respective owners. Comments are property of their posters, the rest © 2001-2009 by me



Garage Plus vBulletin Plugins by Drive Thru Online, Inc.