Carburetor Heat Shield

[rubbinisracing]

I've seen a few cars at local shows that have the carburetor head shield with the engine firing order stamped into them. Are they factory pieces and what and when is there application?

[Mr70]

Yes they are and part of the RPO NA-9 package.
Also known as EEC for Evaporative Emission Control or Charcoal Cannister system ,or California Emissions.All the same animal.
It originally was mandatory on vehicles sold brand new in the state of California & certain parts of Nevada & Montana.
It soon became standard equipment in all states,on most vehicles as the years moved on.

[3macs1]

First I would like to say your collection is wonderful. On the carb spacer I am not sure if they were ever factory installed but we definately bought them over the counter from GM when I raced my 70 Chevelle years ago. There was one for holley and one for quad.They helped with controlling vapor lock and fuel boiling in the bowl especially on the holley with the GM Al intake by preventing all of the heat from getting to the carb especially after shutting the engine off. Some believed this cooler carb would produce a denser fuel mixture and make more H.P. We also used a Gm deflector pan under the GM Al intakes which again I bought over the counter to keep the oil off the bottom of the al intake and the heat down. I am not sure if GM still makes these items perhaps someone more experienced than me can let us know.I still have one of each NOS buried somewhere if part numbers are required.
Joe

[rubbinisracing]

Rick (MR70),

In 1969 and 70 were they only on Calif., Nev.,and Montana sold cars?

[Mr70]

I believe so Howard,but exclude 1969.
This was new for ALL 1970 vehicles.
Again,they had to be sold brand new in those areas to receive that,regardless of where they were built.
The paperwork will reflect this RPO,as well as some revealing details on the original vehicle itself.
This particular carb. heat shield should not be confused w/the A.I.R. system.

[rubbinisracing]

Rick,

Thanks for the great info. I went an looked at 2 of my cars build sheets that were sold new in California and there it was "NA9". Just so happens both cars were built at Van Nuys and are "Special Paint" cars.

Thanks again Rick!

[rubbinisracing]

Rick,

Does an L34 70 Chevelle with the NA9 RPO code on the build sheet use a carburetor heat shield with the quadrajet carb.?

[Mr70]

Absolutely..it was not just for Holley equipped engines.
All 1970 Quadrajets used part #3969837.

[3macs1]

Mr.70
Was the heat sheild and the charcoal canister system the only components of the NA9 RPO code or was there other components added.

[Mr70]

In addition to those two items,there was a seperator box mounted over the rear axle,special vented gas tank and gas cap,and a Special Carb with a fuel bowl vent pipe.
This system took the fuel vapors from the carb.and routed them to the charcoal cannister where they were then returned to the gas tank via the seperator.

[3macs1]

Thank you Sir. I remember the animal now. We started to see them in I think around 71 in canada. I remember guys being scared to fill their gas tanks to the top to ensure fuel did not run back into the lines when they first came out here

[Mr70]

Yeah..They made NA-9 standard on all vehicles after 1970.

[VintageMusclecar]

Was there a part number stamped on the originals, and what (if any?) are the differences between the OE's and later replacements?

[ss427copo]

like this.......? http://www.yenko.net/ubbthreads/images/graemlins/confused.gif
It appears in the 70 Chevelle Assbly. Manual

Jeff

[ss427copo]

one more........

[CamarosRus]

1970 Z-28 NA-9 components...............from Frank Arone's and David James cars


http://img.photobucket.com/albums/v470/CamarosRus/Camaros%20at%20Carlisle%202006/tn_IMG_0830.jpg
http://img.photobucket.com/albums/v470/CamarosRus/Camaros%20at%20Carlisle%202006/tn_IMG_0831.jpg
http://img.photobucket.com/albums/v470/CamarosRus/Camaros%20at%20Carlisle%202006/tn_IMG_0851.jpg
http://img.photobucket.com/albums/v470/CamarosRus/Camaros%20at%20Carlisle%202006/tn_IMG_0852.jpg
http://img.photobucket.com/albums/v470/CamarosRus/Camaros%20at%20Carlisle%202006/tn_IMG_0853.jpg
http://img.photobucket.com/albums/v470/CamarosRus/Camaros%20at%20Carlisle%202006/tn_IMG_0854.jpg
http://img.photobucket.com/albums/v470/CamarosRus/Camaros%20at%20Carlisle%202005/Holly4489.jpg

[CC Rider]

Sorry to dredge this one back up, but I discovered today the fuel in my Holley's bowls was boiling. Found one of these heat shields on Rick's Camaros. Do they help prevent boiling fuel? Thanks.

[Xplantdad]

Yeppers...from what I remember!

[Mr. Chevy]

Rick, it definitely will help.. I use one on my 70 L78 Nova due to the factory low rise intake and it helps with vapor lock.. Before using it I had trouble with same.... After I installed the shield I never had another issue..

Rich

[CC Rider]

Thanks guys! <<GRAEMLIN_URL>>/youguysrock.gif

[kwhizz]

Move to where it's a little cooler..........

[Xplantdad]

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: kwhizz</div><div class="ubbcode-body"> Move to where it's a little cooler.......... </div></div>

LOL <<GRAEMLIN_URL>>/haha.gif <<GRAEMLIN_URL>>/headbang.gif <<GRAEMLIN_URL>>/grin.gif

[70 Forest Green Zee]

Sell car and buy a hybrid....they don't use and gas! Problem solved :-)

[CC Rider]

Maybe I should buy a Nissan Leaf and move up north. <<GRAEMLIN_URL>>/haha.gif

[RPOLS3]

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: 69SUPERSPORT396</div><div class="ubbcode-body">Maybe I should buy a Nissan Leaf and move up north. <<GRAEMLIN_URL>>/haha.gif</div></div>

No - they don't work in the cold...........

[JRSully]

As mentioned previously. If you are running a 569 intake, with factory Holley, in any kind of heat. They are lifesaver, immediately stopped the fuel from cooking on my Nova. Put it on

[mbxlesney]

As Rick stated earlier, I would like to add the NA9 system also had special rubber coated clips mounted on the drivers side fenderwell that the hoses routed through on their way to the PCV on the drivers side valve cover and the vent bowl and base plate on the carb. My Nova used 2 of these clips, 1 lower for the hoses and the upper 1 replaced the all plastic clip for the forward headlight wiring harness. Also the charcoal canisters were different for various applications. My L78 car has a 4 nipple can like the pics of the Z28 that Chuck has provided and L34, L48 versions had a 3 nipple set up 2 next to each other and 1 in the center. I think the 6 and 4 cylinder variations had a 3 nipple setup also but the nipples were evenly spaced apart. The cans also had replacable filters on the very bottom. I had to restore this system on my car and was a lot of fun. The lines were fun as my longer line had pitting. In the assembly manual it also shows that Chevrolet started using a special PVC hose on all cars that did away with the use of the many clamps. I have never seen this hose on any car and wondered if anyone else has seen these before. If interested I will submit a pic.

[mbxlesney]

Here is 2 added pics of the different hoses used. The 2nd one has the 3 clamp setup and the 1st one shows the special molded hose that was used later in production. Has anyone ever seen the molded hose on any CA. sold vehicle???

[70 Forest Green Zee]

Here's the setup from my NA9 equipped 1970 Z28. On a Camaro equipped with NA9,there was a special Holley carb which had a vent line attached to the front of the carb from the charcoal canister, and a special carb heat shield that was exclusive to the LT1 Z28. Note that it is shaped quite differently than the heat shields that came on some Chevy big blocks.

http://i97.photobucket.com/albums/l232/rmitch120/tn_IMG_0178-1.jpg

http://i97.photobucket.com/albums/l232/rmitch120/tn_DSC01720.jpg

[USA1]

Kim,

I have a 10D built L78 El Camino and have RPO NA9. I do not have the moulded hose set up you mentioned. Also, the tee, part 10, is metal. I believe the part number of my canister is 7028024 and has a two letter code and date stamped into the top. I think the routing to the PCV is a bit different too. I think I have a J type moulded hose that is connected from the tee to the PCV. It doesn't have the straight one or two inch piece of hose. It's more like 6 - 10 inches long and hooked like a J. All this is from memory, but I do still have all my original hoses. They're in boxes somewhere in my garage.

Al

[mbxlesney]

Al...It appears that Willow Run started using this hose in or around Jan. 1970 by the revision date. It may have been a short lived hose as I have never seen one before. Maybe someone has a Chevrolet News bulletin on these hoses that can shed light on them. They were probably more expensive to have made than the time it saved them on the assembly line to install the plastic &quot;T&quot; style and clamps. I was curious if any of the 1970 Camaro and Chevelles may have ever showed these hoses in their assy. manuals. Green Z your carb is very similar to mine but the heat shield are definetly different. I heard the Z heat shields are very hard to come by.

[CC Rider]

I'm not a big fan of these shields, but it works like a charm. My garage no longer wreaks of gasoline after shutting the engine off, engine starts easier, and it seems to run better when hot. Thanks everyone.

[mockingbird812]

Problem solved. Gotta love the depth of knowledge round here! <<GRAEMLIN_URL>>/biggthumpup.gif

[CC Rider]

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: mockingbird812</div><div class="ubbcode-body">Problem solved. Gotta love the depth of knowledge round here! <<GRAEMLIN_URL>>/biggthumpup.gif </div></div>

I agree! And I really didn't want to trade the Chevelle for a hybrid or move. <<GRAEMLIN_URL>>/haha.gif <<GRAEMLIN_URL>>/youguysrock.gif

[mockingbird812]

Glad to hear that Rick. You are hard core, for sure!

[Mr. Chevy]

Rick you will get used to the look.. It bothered me also at first but they are technically a correct piece that could have been dealer installed..

Rich