Hi all

I'm having a hard time putting this piece back on my carb? Its a 75 corvette l-48 auto, i think its the original carb.

A few months ago i pulled my carb and rebuilt it... trying to get rid of a stumble off the line, that's mostly gone. I recently pulled it again to clean the intake manifold... found a piece off of my carb... not on the carb. I think it is the fast idle cam. Does anyone have a schematic or know where it goes? I think it has to do with the choke, but in my carb book it do not have an illustration.

One other question, I had the carb really clean no stains, just the metal. It looked great. Now it's got white powder stuff clinging to it, it doesn't brush off. I used parts cleaner and castrol purple to try an get it off, doesn't come off.

By the way i haven't had a chance to start the car up in a while so i won't know if the fix actually works for a few more months ( it's been hard to start) but i will get back... promise hehehe :lol:

thanks guys

ZD

 

anybody?

ttt

 

okay

one other question... Are any of you guys running edelbrocks or holleys, i am kinda leaning toward the holley because of all the parts in jegs/summit.

Opinions?

ZD

 

ZD -
Can you send me a photo or a sketch of the part that need to be installed...? If I know which one you're referring to, I'll be glad to give you detailed directions for installation.

The white substance on your carb is aluminum oxide: corrosion. If you get the carb really clean, it can oxidize slightly in humid climates. Also, if the cleaners you used were not specifically carb cleaners, they can be slightly corrosive to the aluminum/zinc casting. You can arrest and slow down this corrosive process by wiping the carb surfaces down with a rag that's been moistened with some WD40.

If you're going to do a carb swap to something non-original, go with a Demon. We're installing them out here and picking up over 2 tenths over comparable Holleys.

You can e-mail me with info on the carb linkage problem at:

daytime
lars.grimsrud@lmco.com

eve
v8FastCars@msn.com

 

Perhaps this will help you describe the part to Lars.

 

thanks lars, i'll email you a scanned outline of the part.

The demon car, are you using the race or the street? Did you buy it out of summit or jegs?

Thanks

ZD

 

Contact blkblt over on the C1/C2 Forum and check out his threads and postings on the Demon swap ("Lars and the Demon") He picked up the 750 vac secondary from Summit, and it was quite reasonable. He has all the part numbers/specs/info.

I'll wait for your e-mail on the part description and tag you right back with assembly instructions.

 

Zach -

The lever is the secondary lockout lever. It prevents the secondaries from opening when the engine is cold, thus preventing excessive engine wear and/or damage from full-throttle application on a cold engine (not good). In my Q-Jet tuning paper, I jokingly call this the "primary jet tuning lever" sice it can be used to lock out the secondaries during primary jetting and tuning operations. It is activated by the fast idle cam: when the fast idle cam drops down off the fast idle setting, it kicks the lever away from the secondary lockout pin and allows the seondaries to operate. The carb and engine will operate just fine without it, but you need to make sure you don't nail the throttle while the engine is cold since you won't have its protection. On racecars, we intentionally remove the lever so that it won't inadvertently lock out the secondaries at an inopportune time.

It is installed on a cast "pin" that sticks out of the carb housing just forward of the secondary throttle shaft, passenger side, about 1/2" above the secondary shaft. It simply pivots and flops around on the pin. The end that has a small sharply-cut notch in it is the end that engages with the secondary throttle shaft lockout pin. The pin has a flat spot on its end that "seats" in the lever notch. The lever is retained on the cast pin by the large sheet metal plate that holds the entire choke assembly to the side of the carb. This sheet metal assembly caps off the pin, and keeps the lever sandwiched in place. The lever is just out of sight on the photo posted above - just behind the rear edge of the choke housing.

Installing the lever at this point will require some finesse. If you have an electric or stove type choke (with the big, round, black cover on the side of the carb), the screw that attaches the choke assembly to the carb is located under the black cover. You need to removethe black choke cover and gain access to the single attach screw inside the choke housing. Once you get this screw removed, you want to be very careful. If you pull the whole choke assembly right off the carb, there is a little choke actuation lever inside the carb on the end of the choke shaft that will fall off and drop to the bottom of the carb. So, with the attach screw removed, you want to pull the rear edge of the assembly out just far enough to allow the lockout lever to be slipped into position on the cast pin. Then slap it all back together and install the screw and the choke cover.

Tag me back if any of this is confusing or if i did not do a god job of explaining things. I can shoot you a photo of the instalation if you'd like.

 

Lars-

Does it go on a pin that is on the carb or on the choke housing? there is one on the choke housing that is redish (rusted i guess) but that is the only pin that i see... i already pulled the housing, i'll have to wressle the green peg back onto the secoundaries opener rod thingie (specific aint i :D )

Thanks for the help but slightly confused :confused:

ZD

 

The boss, or pin, that the lever goes on is a cast boss that sticks out of the carb itself - it's not attached to the choke housing. Look at the secondary throttle shaft on the passenger side. The shaft has a thin steel pin stuck through it, about 3/32" diameter and about 3/4" long. The upper part of this pin (facing forward) is flattened. This is what the lever engages with. If you look at the end of this pin, then go about 3/4" up and 1/2" forward, there is a cast boss sticking out of the side of the carb (float bowl). The lever hangs on the end of this boss. Let me know if you see it.

 

i see it... how exactly do you get the "intermediate choke lever onto the intermediate choke shaft?" I think i can get the Secondarie lock out cam one thanks lars!!!

(now that i know what i'm looking for i can find the names in my carb book :D )

ZD :cheers:

 

I see you have the correct nomenclature for the parts down pretty good! Now, for those of our readers who don’t know what the intermediate choke shaft is, allow me to translate your question:

“How the heck do you get that little choke lever down inside the carb hooked back up to the stinkin’ shaft on the choke housing when you stick the housing back on the carb???”

Good question, and here’s the technique:

First, remove the screw that holds the choke lever arm to the choke shaft on the passenger side of the choke plate (right at the top of the choke air horn). Remove the lever, and remove the rod that sticks down into the carb. This rod is the intermediate choke rod. (On early Q-Jets with divorced chokes, i.e. no big round black doo-hickey on the passenger side of the carb, there is no screw on this lever. You simply pull the clip off the rod and disengage it from the lever.) As you pull the rod up, the little lever arm on the lower end of the rod will come up with it. Be careful! You don’t want to allow the lever to drop off the end of the rod. If it does drop off, you need to fish it out of there with a magnet, piece of wire, or tiny needlenose. If all else fails, you’ll need to remove the carb and turn it upside down to get the little sucker out.

With the rod and the lever out of the carb, proceed as follows:

You already have the entire choke assembly off the carb. Make sure the counterweight (the thingy that’s slipped onto the fat sleeve sticking out of the choke housing) operates freely, and that it’s resting on top of the actuating lever arm that’s attached to the intermediate choke shaft (that’s the green shaft that comes out of the choke housing). With the black cover removed from the choke housing, all parts should operate freely and easily.

Yank the vacuum hose off the choke pulloff diaphragm to get it out of the way. Make sure the secondary airvalve rod is attached to the choke pulloff (it’s “Z”-shaped on its end).

Now, hook the intermediate choke lever onto the end of the intermediate choke rod and let it dangle there. Carefully lower the rod with the lever dangling from the end into the carb and look into the hole in the side of the carb that the choke intermediate shaft will go through. Lower the rod and lever until the flat-sided hole in the lever lines up with the hole in the side of the carb. You can see it hanging right there.

Now, engage the secondary airvalve rod into the secondary airvalve slotted hole and slip the entire choke assembly into position: the choke intermediate shaft (the doo-hickey green shaft coming out of the choke) will slip in through the hole in the side of the carb and it will hit the intermediate lever that’s dangling from the rod. Since the angle is all wrong, it will not engage in the lever. Now, once the shaft is pushing against the dangling lever, slowly let the lever drop by lowering the rod that you’re holding in the other hand. This will rotate the lever around the shaft, and the shaft will suddenly engage into the lever once the lever hits about the 90-degree position. The entire choke assembly will now slip into position.

But wait! The lockout lever that you started with hasn’t been installed!

With the choke intermediate shaft engaged into the choke intermediate lever, you can now pull the entire choke assembly away from the carb enough to slip the lockout lever into position, but without loosing the intermediate lever off the intermediate shaft. As soon as the lockout lever is in place, shove the entire assembly into position and get that screw installed before you loose it…!!

Once you’ve done this a few times, you can hold the lockout lever in place with one hand; feed the intermediate lever and rod down the carb with the second hand; and install the choke with your third hand. I just showed my 19-year-old son how to do this, and told him he could amaze his friends with this trick. He told me his friends don’t know what a carburetor is….

Tag me back with any questions. I’ll be more than glad to give you a call and talk you through it.

 

lars... is there anyway to install the intermidiate choke lever with the choke housing installed, i cant get the screw out of the green rod, i'm afraid i'll strip it... i guess i might be digging through old carbs at junk yards a while :(

Thanks for the help... doe the demon carbs have stuff like this too? I dont like the super tiny parts that you cant get a light on... and cant remember how you did it last tim. :crazy:

Thanks again

ZD

 

You don't need to remove the shaft out of the choke housing - you install the whole thing as one assembly - you only need to have the cover off the choke housing in order to access the attach screw and to remove the spring tension from the choke components. Don't bother pulling the lever off the intermediate choke choke shaft inside the choke housing - no need for that. I can arrange to shoot some pictures of the process for you over the weekend if you'd like - just let me know.

 

that would be great lars!!!

Thanks for helping me out

ZD :cheers:

 

I'll dig a carb out of the basement this evening and head over the C1/C2 Forum member "blkblt" house - he has a really nice dig camera and a site to post up the photos from. I'll disassemble the choke area and yank the intermediate rod/lever out of it. We'll then shoot a concise step-by-step reassembly sequence for you and post it up here. It'll be either this evening (Thursday) or sometime tomorrow (Friday). Will that work?

 

lars... any time will work (this week next week next month), i am just thankful to have such a wealth of knowledge that is willing to help us not so great gear heads a kick start. If you ever write a book drop me a line, i would love to buy one :yesnod:

In the long run i think you'll be working on my carb sometime :D

Thanks again
ZD :seeya

 

ZD :seeya :

I just got an e-mail from "The Professor" (Lars). We will shoot the sequences later today, probably. I will post them on this thread, not on C1-C2. If you want information regarding Demon carbs, let me know (re: numeric comparisons Lars and I ran), or check out their website at:
http://www.gpt300.com/demoncarbs/index2.htm

I am running a Speed Demon 750 vac sec, EC on my '66, 427/425. The "correct" Holley is boxed and will go with the car if it is ever sold. I'll never put another Holley on it on my watch. :U :D

***********
Jeff
'66, Incorrect L72
"The silver Beast"
Keep on :seeya :seeya :flag

 

BLKBLT

is your car easier to start after the change? I would like to have mine (75) start up like or similar to a fuel injected car!!!

ZD :cheers:

 

ZD:

My 66 has always (in my 3 years with it) been a fast and reliable starter. Tap the pedal once and turn the key and she explodes to life at any temperature. Very nice... :D :yesnod:

I can see no difference in start-up between the Demon and the Holley. Aside from the additional 28 ponies to the rear wheels that we documented with the computer (and in driving!!), the big noticeable difference is throttle response and mid-range acceleration and deceleration....it is very smooth and much like FI, IMHO. The Holley I removed was fairly new (the old "correct" one is gathering spiders in one of Lars' corners) and was tuned by Lars, so it was running about a well as you can get a Holley to run, but the difference between the two carbs was/is significantly noticeable. Frankly, it has blown me away, since I NEVER expected anything that dramatic from a mere carb change. Needless to say, both Lars and I...and several other "LarsGarageBums"...have become believers. :yesnod: :yesnod: :lol:

********

********
Jeff
Ô66, Incorrect L72
ÒThe Silver BeastÓ
Keep on :seeya :seeya :flag