I'm rebuildind an e4me that was rebuilt before by someone before I got it. The plastic insert anenoid cavity is missing. what is the purpose of this part, just to keep gas out of the anenoid cavity?

it's part #60 one page 6C1-16 athttps://www.thirdgen.org/forums/carburetors/426296-e4me-quadrajet-service-rebuild.html

 

Has anyone ever seen an E4ME that came off a Camaro and had the plastic insert in the anenoid cavity?

today my friend gave me a E4ME off an 81 Camaro with a 305. I cracked it open and just like the E4ME carb off an 85 Chevy, there was no plastic insert in anenoid cavity under the M/C plug. both carbs look identical inside and out (17081204 and 17085204)

 

Most remanufactured carbs have that anoid removed also. It won't hurt the performance of the carb to leave it out. The biggest thing to consider is that the intent of the anoid is to catch dirt and debris that might get past the rubber gasket around the connector, and to work as a semi baffle to the fuel flow around that cast horn. The cavity will fill with fuel whether the anoid is present or not. If you want a new anoid, the only suggestion I have is a new M/C soleniod kit that I found at Carbs Unlimited. They don't sell the anoid seperatly but it is part of their "complete" kit that sells for about $65. Keep a keen eye on the tolerance of the O-ring that you install over the M/C solenoid connector, I have seen many rebuild kits include one that either won't seal the gap or are to tall and won't let the air horn sit flush with the carb body. Cranking down on one that's to tall is a bad idea because it invites stuck assembly screws, and promotes the possibility of warping the air horn, a common problem with old style non electric Q-Jets though that happened for a bit different reason with those.

 

thanks for the warning on some inserts being too tall! Seems like Rochester could have designed / used a couple strips of metal like on the pump well. The insert is'nt worth $65 thats for sure!

my thoughts are that besides keeping dirt out (which makes sense I guess) is that that if the cavity keep fuel in it, then on hot days it might waste a fair amount of fuel through evaporation/fumes, but maybe that's not a real big concern?

 

That O-ring on top of the connector should do a reasonable job at preventing vapor loss if it fits correctly. The pump cavity is covered by the plate gasket, the old ones used to have a wax like treatment on them that the new ones don't seem to have anymore, and the pumprod that extends out of the airhorn has a rubber seal staked into the cavity on the under side of the airhorn.
One other quick note about that aneniod is that the originals were more like rubber, similiar to the kind you find under the brake fluid resevior or clutch fluid resevior. They often distorted with age and accumilation of heat cycles, thats why you will often see them discarded on the older carbs that have been rebuilt over the years. The replacement one I mentioned is made of hard plastic it might be phenol resin I'm not sure. The originals also had a strip of white plastic blocking off part of that cutaway similar to the strip of metal on the pump side, those usually broke the first time they came out.

 

Huh, I was under the impression the aneriod cavity was there to help compensate for altitude changes while driving. Who told me that then?!?

 

well, I don't know about altitude compensation but it sounds technically promising


here's what I did Sonic,

I stuck a hunk of solid metal bar in there... honest, and then, ok, I'll wait 'till you stop laughing... alright then, my idea is that the metal in the cavity will now take up space and thereby possibly reduce a small amount of gas from being wasted, there's still no proof on this but that's what I did