Cowl Induction Flapper on a '71

12535 Views 19 Replies 7 Participants Last post by DZAUTO, Jul 13, 2013

Willie375hp

Discussion Starter · Jun 29, 2013

Hi, not sure where to post this so if it's in the wrong spot go ahead and move it...

Anyways, I've seen many 70-72 chevelles with their flapper door working that do not have the factory air cleaner. So I've been looking at some reproduction kits on OPGI and such and I was wondering if I could get the flapper door to work without paying the extra for the air cleaner and such. I'd just like to get the flapper door working as cheap as possible, it doesn't matter much to me if it's not correct or doesn't do its correct function. Just trying to get the flapper door to open and close, just because it looks cool lol

With that being said, if this can be done...Can somebody post a link with the correct parts needed to make this work? I'm just completely in the dark with this

Thanks,

Wilbur

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DZAUTO

· #2 · Jun 30, 2013

First of all, what parts do you have? Once it is known what parts you have, then we can let you know what you need.
Next, to specifically answer your question, YES, the outside flapper door can easily be made to work totally independant of whatever you have for an air cleaner----------------but first we gotta know what parts you already have.

I have a different check valve in the vacuum line on our 70, so the flapper on ours closes a little more slowly than they did from the factory. Under hard acceleration, the door should open quickly, then close somewhat slowly when vacuum increases.
Here is how ours works.

70 nialator

· #3 · Jun 30, 2013

These should get you there.. Assuming you have a correct flapper hood…

http://www.ebay.com/itm/70-71-72-Ch...ts=Model:Chevelle&hash=item53db22a326&vxp=mtr

and

http://www.ebay.com/itm/70-72-Cheve...Parts_Accessories&hash=item1c33f88376&vxp=mtr

and

http://www.ebay.com/itm/1970-1972-C...ts=Model:Chevelle&hash=item53f02c889c&vxp=mtr

This is how I know…. (My car)

MAKE SURE to adjust the 2 screws for the MAX down on the door or you WILL bust the bottom fins.

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Alan F

· #4 · Jun 30, 2013

http://www.ss396.com/mm5/merchant.mvc?Screen=PROD&Store_Code=chevellecamino&Product_Code=ACX-970

LevonH

· #5 · Jun 30, 2013

70 nialator said:
MAKE SURE to adjust the 2 screws for the MAX down on the door or you WILL bust the bottom fins.

Can you explain or post a picture of this? I've heard about it but never seen it done.

70 nialator

· #6 · Jun 30, 2013

On both the hinges there are threaded holes on the bottom and no one ever knows what they are for… until it’s too late…. You’ll have to find the correct size screws and adjust them so the door can ONLY set flush in the hood, goes any lower and you bust stuff. I’ll try and get a pic soon. This information should be enough to get to there though..

LevonH

· #7 · Jun 30, 2013

Thanks Darren. I see the holes in the brackets. Now to figure out the screw size ....

Willie375hp

Discussion Starter · #8 · Jun 30, 2013

The only parts I've got right now are the flapper door itself and the two door supports that hold it, It's just kind of held in place at the moment on the car.

DrPepper

· #9 · Jun 30, 2013

DZAuto, you mention a check valve in the vacuum line. I don't recall seeing a check valve in the line.
Where did you get your check valve? I like the way the door closes slowly.

DZAUTO

· #10 · Jun 30, 2013

DrPepper said:
DZAuto, you mention a check valve in the vacuum line. I don't recall seeing a check valve in the line.
Where did you get your check valve? I like the way the door closes slowly.

The check valve (it's a one-way flow valve) was part of the complete CI hood system. It only goes in the vacuum hose (hose connects to MANIFOLD vacuum) one way. It is long discontinued from GM, but all the aftermarket sources sell a repo valve. The valve I use is NOT the correct valve. I got it off a mid-80s GM car in a salvage yard. It controls vacuum flow to a valve in an air cleaner snorkle. I forget just what kind of car it came off of, but they were VERY common and I got 2-3 of them. It is plastic, white on one end, black on the other end. At shows, I replace it with one of the repo check valves to look "correct". The check valve is the key to having the flapper function in a cool maner. If no check valve is used, the door opens quick and closed quick.
If you have the flapper door and the hinges which mount it to the hood, then it sounds as if you need the special shouldered screw/nut and the vacuum pod which pulls the door closed and the check valve and a length of hose. It would also be good to have the screw stops as mentioned above.

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DrPepper

· #11 · Jul 1, 2013

I've got all the pieces / parts for the flapper door. Just don't have the check valve, yet.
Thanks for the info the source of your check valve. When I have time, I'll check out the wrecking yards.

Alan F

· #12 · Jul 1, 2013

For the OP: Outer door will function without the check valve. Last I looked Ground Up sells a repro valve but they aren't cheap.

DZAUTO

· #13 · Jul 1, 2013

Alan F said:
For the OP: Outer door will function without the check valve. Last I looked Ground Up sells a repro valve but they aren't cheap.

That is exactly correct. But for my preference, if the check valve is not in the hose, the door closes tooooooooo quickly!

Willie375hp

Discussion Starter · #14 · Jul 1, 2013

So do I just need to order this without the flapper door and air cleaner?

http://www.opgi.com/chevelle/1971/sheet-metal-body-panels/firewall-cowl/KCI507/

Alan F

· #15 · Jul 1, 2013

The kit in that link has much more than you need to just make the outer door work. You need the flapper door, the supports, the pivot bolts, screws to hold the supports to the hood, the vacuum pod, the vacuum pod mount, screws to hold the mount, screw to connect the pod to the door and vacuum hose.

70 nialator

· #16 · Jul 1, 2013

He wants it to close slow.. you can get them all day long for 25.00. I'm sorry I can not attest to how well these work though, I don't use or want one, I like mine more reactive.

http://www.ebay.com/itm/70-71-72-Ch...Parts_Accessories&hash=item3f26470755&vxp=mtr

Willie375hp

Discussion Starter · #17 · Jul 12, 2013

Bought all the parts you guys told me to get. Just put them all in today and it works like a charm! Thanks so much!

DZAUTO

· #18 · Jul 12, 2013

Willie375hp said:
Bought all the parts you guys told me to get. Just put them all in today and it works like a charm! Thanks so much!

Excellent!
Glad to hear that! :thumbsup:

71350SS

· #19 · Jul 13, 2013

I've been planning on replacing my missing flapper door for some time now and this is one of the pieces I am going to use.Its cheap enough that it won't kill me if it doesn't work as I want it to work,so thats a plus.
http://www.rockauto.com/catalog/moreinfo.php?pk=87670&cc=1042591
Its listed as a vacuum delay valve which is exactly what is needed I tried to find more information on the AC delco site but came up empty,so I'm gonna buy it and try it as soon as I find a replacement outer door.I looked it up on Rockauto.com as an 82 El Camino with a 3.8L (231cid) V6 but lots of carburated late 70's and early to mid 80's era emission controlled cars used these in their ignition/emission control systems.If you click on the part # it will give a list of cars that used the same piece if you want to hunt the boneyards.

DZAUTO

· #20 · Jul 13, 2013

71350SS said:
I've been planning on replacing my missing flapper door for some time now and this is one of the pieces I am going to use.Its cheap enough that it won't kill me if it doesn't work as I want it to work,so thats a plus.
http://www.rockauto.com/catalog/moreinfo.php?pk=87670&cc=1042591
Its listed as a vacuum delay valve which is exactly what is needed I tried to find more information on the AC delco site but came up empty,so I'm gonna buy it and try it as soon as I find a replacement outer door.I looked it up on Rockauto.com as an 82 El Camino with a 3.8L (231cid) V6 but lots of carburated late 70's and early to mid 80's era emission controlled cars used these in their ignition/emission control systems.If you click on the part # it will give a list of cars that used the same piece if you want to hunt the boneyards.

John,
That is EXACTLY the check valve that I use on the 70. I closes the outer door somewhat slower than the stock, original checl valve, which is the way I like it. :thumbsup:

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