Converting Rochester Quadrajet to Manual Choke?

ClydesdaleKevin · April 27, 2012, 11:22 AM

I think Lefty did this with his Georgie Boy, and now I'm thinking it might be the best choice for us as well.

I have a 454 with a Rochester Quadrajet. How difficult is it to install a manual choke, where do you get one, and how much do they cost?

I'm still sorting out my own choke issues, and while I do have it working fairly well at this point, its still not quite right. If I adjust it to set completely, thus starting the rig easily, the high idle won't kick down. So I have it set at a compromise, which allows the choke to work somewhat and keep the high idle at warm up, but will kick down now...however, its a compromise for sure, and gives the carburetor a very slight but noticeable hesitation from acceleration to kicking down. With the choke turned enough to be disengaged completely, it starts hard, but runs perfect otherwise. Really gotta think about a manual choke.

Any thoughts, ideas, or suggestions about this? The carburetor was recently rebuilt by a trusted shop in Arizona, but now I'm thinking some of the issues it was having before the rebuild could be choke related. And since I couldn't leave the RV with them...being fulltimers and all...they did the best they could with the adjustments.

Since it runs perfectly with the choke fully disengaged, it seems to me that a manual choke would be the perfect solution...every other adjustment I make seems to just be a compromise otherwise. We just drove it 1300 miles with no choke, and it ran like a dream and got us a solid 8mpg.

I spent the last 2 mornings tinkering with the choke and dashpot settings, and I don't think I can get it balanced any better...but its not running nearly as well as it did getting here.

Kev

ClydesdaleKevin · April 27, 2012, 12:53 PM

I looked all over the internet and can't find a Q-jet specific conversion kit. Dorman-Help, found at Napa, OReilly's, and Advanced Auto has a cheap conversion kit that says "fits most carburetors" or "fits 95% of all carburetors."

Anyone know if its compatible with a Rochester Quadrajet, or where to get one that is?

Kev

Lefty · April 27, 2012, 07:13 PM

Kev,
I purchased a universal manual choke kit from AutoZone.. The one I purchased had the cable assembly, a dash mounting bracket, a universal L-shaped cable holding bracket, two different depth black plastic choke adapter caps, and some assorted shaft adapters and clips & stuff. I think it was only about $10 bucks... I'm about 90% sure it was a "HELP" brand.

Here are some shots of my installation, and I'll explain what I did as I go.

First, you have to remove the old electric choke housing, which is held in place by three screws or rivets... Be sure to save the little spreader things that go between the screw and the housing, as the kit doesn't include them & you'll need them later. Install the included shaft adapter, which slides into the housing and engages the lever inside to operate the choke plate. Choose the right replacement cap (mine was the shallow one) Install the clip assembly that holds the cable, and reinstall the screws/rivets.. as you can see, mine was riveted on. look closely and you can see the load spreaders underneath each rivet.. these help hold the cover securely. Oh, and I dropped the tiny brass screw that holds the cable once it's in the cable lock, which is why mine is bent a couple times around it instead.

This lever here, if it ever comes off the other end of the linkage down in the hole, is a real pain in the neck to put back on without taking the top off the carb... It took me a couple hours to get it to pop back in place, and I had to fabricate a couple of hook tools that were small enough and long enough to reach all the way down.

This is the L-shaped bracket that holds the cable behind the carb. It mounts to the intake manifold. Note that I had to cut the top of it off to keep it from hitting the bottom of the air cleaner, as well as giving it a twist so it aligned up better. This is what keeps the cable from pulling forward when you pull the dash knob out, as well as keeping it from pushing back when you push in on the dash knob.

Here's a shot showing where it mounts, as well as how the cable is routed.

Here's the same cable as it goes over the left valve cover, headed towards the outside of the A/C compressor.

Here you can see the cable going up beside the compressor, and thru a small hole I drilled in the carpeted area under the dash.

Closeup of it passing thru the floor... I drilled the hole just barely big enough to prevent any engine noise or air coming thru the hole.

And here is the dash knob in its holder screwed to the bottom edge of the dash (Make sure you hit solid wood or metal). There is a large nut on the backside that holds the cable assembly firmly to the bracket.

This shot shows the completed dash knob, and where it's located a little better... It's to the right of the steering column, directly above the left edge of where the doghouse sits. I could have routed it higher, and drilled a hole in the dash... but this location is handy and was a lot simpler.

Assembling the cable is done by threading it thru the dash mounting bracket first, then the hole in the floor, down past the A/C compressor, over the left valve cover about 2/3'rds of the way down the cover, across the backside of he intake behind the carb., thru the L-shaped bracket, and finally to the bracket on the choke housing.

Need more info, let me know.

ClydesdaleKevin · April 27, 2012, 08:19 PM

Thank you SO much for the pictures Lefty! That was way over and beyond the call of duty! I really appreciate it!

What I was having a problem with searching on my own was a compatability list...none of the kits I saw SAID they worked with a Quadrajet.

I am so going to do this next week, and I'll let you all know how it works out! It obviously allows the high idle linkage to still work, but give you control of the choke manually.

Thanks again Lefty! I think this is just the thing we need!

Kev

Oz · April 27, 2012, 08:30 PM

That was indeed an exceptional reply by Lefty. We have so many members, particularly the long time ones, who go to these same great lengths to help each other! You all are truly a blessing to everyone. Now, in response to your statement, "I'm still sorting out my own choke issues." The answer is simple: Stop pissing Patti off and she'll take her hands off your throat.

Lefty · April 27, 2012, 08:50 PM

lol Mark..

And thank you for the kind words. I had to remove the doghouse anyways to check the brake fluid and trans fluid today anyways, so it really wasn't any problem.

And in answer to you Kev, yes, it allows for the original high idle linkages to work without any modifications to them... the step links are located behind the choke housing, and operate by gravity. When you press the gas pedal, they swing around and engage the throttle shaft as long as the choke is in the closed position, holding it slightly open. When you push the choke in to open it, they will still be engaged and it will still run at fast idle until you touch the gas pedal, and they will disengage to your regular slow idle.
One thing, to close the choke, make sure you press the gas slightly while you are closing it, this takes the pressure off it and engages the high idle at the same time.

ClydesdaleKevin · April 28, 2012, 08:49 AM

I'm actually looking forward to doing this conversion. So on yours, what did you do, rerivet the plastic cover back in place? When they rebuilt my carburetor, they drilled out the rivets and tapped the holes and used screws, so its not an issue with mine, but I was just wondering if that is what you did.

And I know that linkage you are talking about...the one that goes down into the top of the carb body and barely hooks onto a flat metal piece that the choke shaft goes into...and yes...it IS a pain in the butt to get in all lined back up...it took me the better part of an hour yesterday when I removed the choke body and tried to get it back in. I did finally figure it out, but its not easy! I ended up unscrewing the one end from the butterfly, which allowed me more play room to flip the bigger end of that flat metal piece so that it faces the front of the engine...and then it still sits lower than the hole in the side of the carburetor. I used a long skinny screw driver to find the hole and line it up, and then had to wiggle it all back in place. And then reattach the top of that little rod to the butterfly.

LOL Mark! Patti had nothing to do with the choke....lmao!

Thank you again Lefty...that was awesome, pictures and all!

Kev

ClydesdaleKevin · April 28, 2012, 08:56 AM

Oh yeah, one last question.

The kits comes in 2 versions, a car version with a 5 foot cable, and a truck version with a 7 foot cable and an extra bracket. It looks like you got away with the shorter cable version.

Just checking to make sure!

Kev

Lefty · April 28, 2012, 10:03 AM

My choke was riveted on. I've seen them both ways, never understood why Rochester did some with screws and some not. I already had a good rivet gun, so it wasn't any problem to reattach it... I used my Dremel tool to cut the heads of the old rivets off, and a center punch to knock them out... but drilling them works too.
I think the kit I got was for the truck...not positive, but I'm pretty sure.
It's easy to cut the cable shorter if it's too long. Just pull the cable out of the housing, cut the outer housing to length, then push the cable back in and cut it to length.
Yup, that flat piece is the part of mine that came loose... It took me a long time to get it fished back into position, and was a royal PITA. That's why I warned you. lol

ClydesdaleKevin · April 28, 2012, 09:00 PM

Thanks again Lefty! I'm going to tackle this project this coming week, in between building a small run of catapults.

Kev

ClydesdaleKevin · May 01, 2012, 08:06 PM

While I was out picking up pizza and beer this evening, after working on the catapults all day, I stopped in at an O'Reilly's Auto Parts Store...and there, gloriously, was the Dorman HELP truck version of the Automatic to Manual choke conversion kit...10.99!

Sold!

Hopefully I'll have time to install it before Friday!

Kev

ClydesdaleKevin · May 09, 2012, 06:23 PM

I got the manual choke all installed today, and it works great!

I got to thinking about toggle switch idea that would light up the choke light on the dash if I forgot to turn the choke off, and realized it was a pretty stupid idea after all...lol! I mean, the high idle won't kick down if the choke is on, so it would be pretty hard to forget it was open.

Putting on the manual choke kit wasn't hard, just more involved than I anticipated...and I'm very glad I got the longer cabled truck version and not the car version. By the time the cable was routed to my satisfaction (and I'm pretty anal retentive with cables from my Navy and bicycling experience), there was only a foot or so of extra cable to be cut off. The linkage hardware is pretty flimsy, so I used a heavier cinch bolt and nut, square drive, so it wouldn't slip in the shaft coming out of the new plastic cover that replaces the electric choke, and that is when I realized the inside linkage, that engages the rod that moves the butterfly, was rotating slightly on the shaft! Cheap Taiwan crap! Anyhow, turned out they just didn't peen the metal enough, so a punch and my hammer took care of that.

I drilled a 3/8 inch hole right in the dash panel, right under the ignition switch, and mounted the pull knob there using a washer on either side of the panel for strength, and it looks great! Looks like its supposed to be there...lol. A few zip ties here and there to keep the cable at a gentle arc and true, and voila...finished!

So, a quick check of all the vacuum lines and it was time to start the engine. Throttle pedal pressed, choke engaged....VROOM!!!

I left the air cleaner off so I could inspect the cable for too much play or whatnot, but it was perfect. I let it warm all the way up, turned off the choke, hit the pedal, and it dropped right down to a nice 700 rpm, purring like a kitten. So the high speed idle is right where its supposed to be, 1800, as is the low.

All done!

One more project down, many more to go!

Kev

recycled55 · May 09, 2012, 11:06 PM

Its been a realllyyy long time since I messed with a choke conversion but I think after you start the engine and its running on high idle you can push the choke in and the idle will hold on high until you tap the gas pedal. It doesn't have to be closed until it warms up. Closed is only for start up.

ClydesdaleKevin · May 10, 2012, 09:29 AM

Thanks Recycled! I forgot to mention that that was what I did. I started it with the choke closed (knob pulled), and then was able to push the choke knob back in right away and it still ran perfectly on high idle. I'm guessing that on a really cold day, it might have to stay closed longer, but it was around 72 degrees outside when I did the conversion and tested it.

Once I pushed the knob in, the high idle speed dropped about 100 rpm, which was fine by me! I always thought 1800-1900 RPM was a bit high as a high idle speed with a cold engine, but that is what the specs call for.

Kev

Froggy1936 · May 23, 2012, 12:30 PM

Hey Kev The idle specks are goofy 1100 RPM high cold idle is plenty and 600 RPM hot is good (as long as engine does not stall when put in gear) I have mine set at 1000 RPM cold & 600 hot in Neutral. The slower the better for fuel mileage and who wants a cold engine lacking full lubrication spinning at 1800 RPM I also never run it up over 4500 RPM & then thats only in 1st gear Frank