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Old 01-02-2012, 06:31 PM   #1
zac
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Shaft bushings in Q-jet throttle plate

Has anybody out there done this? Where did you get the stuff, and how much did it cost? Was it easy to do? Anything you have to offer is appreciated. It's time to make the carb on my '70 work right. Thanks
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Old 01-02-2012, 06:52 PM   #2
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Re: Shaft bushings in Q-jet throttle plate

Buy 'em here:

http://www.cliffshighperformance.com/bushings.html

This will give you and idear on what's involved:

http://quadrajetcarburetors.com/bush...tructions.html

Gary
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Old 01-02-2012, 07:01 PM   #3
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Re: Shaft bushings in Q-jet throttle plate

I know a crazy old hillbilly, that used Brigg&Stratton valve guides, cleaned up with a Khoeler guide reamer, for best fit. Built the carb, & spent the better part of a week tuning. trust me, that Q jet is not for the "faint of heart"! The old bioch ran like stink on a 425 cad in my old longhorn, & it ran like stink on a 325hp 327, in my old flatbed. Biggest mistake I made, I traded that carb , for a new 650 speadbore Holley! That old Q-jet out Holleyed the Holley Some things can be done for very few dollars, if you understand mikes & reamers & are willing to tune till you "puke"! That old Q jet, is best left to the pros. Not saying that I am the pro, but I built 3 of thos carbs that yr.....2 worked great & the last 1 fell in the trash can. crazyL
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Old 01-03-2012, 09:08 AM   #4
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Re: Shaft bushings in Q-jet throttle plate

Why do you think the bushings need replaced? Are the bushings so worn out the shaft is sticking or does the engine smooth out when you spray a little water on the shaft momentarily sealing it?
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Old 01-03-2012, 09:53 AM   #5
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Re: Shaft bushings in Q-jet throttle plate

Lots of slop on the primary side, very high mileage carb, it's January and I got nothin else to do. It doesn't have bushings now, it has never been redone.

If possible I'd like to hear from someone who has actually done it. If the instructions tell you everything you need to know, then great--say so. But the kit to change the 203 transfer case in my '79 to part-time had instructions, and they sucked. Having said that, the link to instructions that Gary posted looked pretty good.
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Old 01-03-2012, 01:25 PM   #6
HEI451
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Re: Shaft bushings in Q-jet throttle plate

Why do you only want to slightly reduce the air leak with a solid bushing, when you can virtually eliminate it with a different "filling" material?

I do this all the time, and have one to do this coming weekend. I learned this when I worked for Holley in the race carb department,mbut use it on every carb I do, especially Q-Jets.

A solid bushing only takes some of the air leak away, because it still requires a clearance so the throttle shaft doesn't bind when the carb is retightened back to the manifold. The reason for the clearnace, binding, or, not causing it.

The right way to bush a throttle shaft is with TEFLON. On most Q-Jet's, the actual load surface in the base plate is not large, but, at the throttle bore edges, not all the way to the outside edge of the shaft bore. Most Q's have a .030 larger bore on the base plate from that load carry area, to the outside of the base plate. This .030 area is perfect to use a piece of .014/.015 teflon sheet (available from most better hobby stores), cut into the bushing. Yes, in theory, there is NO clearance, but, the teflon doesn't stick, nor bind the shaft, so, maximum sealing, no binding, and no outrageous machining work needed.

Q-Jet's are notorious for having binding issues when the front hold down bolts are usually way, way over tightened, literally bending the carb, top, body and base plate.

Also, when you refit the throttle plates after bushing, please, use a stainless steel button head Allen screw, Lock-Tite in place, and stake the threaded end into the shaft, to make absolutely syre they are tight, mand stay that way. To "qualify" the throttle plates in their bores, close the shaft and plates all the way against the throttle bores in the base plate, then, tighten the plate screws. When done, there should be easy movelemnt of the plates off the bore sides, without the plates sticking in the bores. Don't be surprized if you have to go over the qualifying operation a few times, it is extremely important to get it right.

Please note, on a very few Q-Jet's, and all the other carbs that don't have the bigger cut in the throttle shaft bores, I chuck the base plate into a drill vise, shaft bore up and down, then, align the bore with a straight shaft into the drill press chuck, then, remove the shaft and install the correct drill bit to create the teflon bore, and cut the bore down a bit, but, NOT all the way into the throttle plate side of the throttle bore. This way, I create a step at the inner edge of the shaft bore, to hold the teflon from migrating into the throttle bore. The stuff that hangs off the ends of the shafts keeps the teflon in place on the outer edges of the shaft bores.
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Old 01-03-2012, 06:13 PM   #7
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Re: Shaft bushings in Q-jet throttle plate

The teflon sounds interesting, but wouldn't a thin layer wear out pretty quick, putting you right back where you started?

My concern with the Ruggles kit is that it would be almost $80 to get it to my house. I would think he could do it for me personally for that price if I sent him the base plate.
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Old 01-03-2012, 06:20 PM   #8
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Re: Shaft bushings in Q-jet throttle plate

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Originally Posted by zac View Post
The teflon sounds interesting, but wouldn't a thin layer wear out pretty quick, putting you right back where you started?

My concern with the Ruggles kit is that it would be almost $80 to get it to my house. I would think he could do it for me personally for that price if I sent him the base plate.
Cliff bushes EVERY used carb, he builds. I believe the bushing material is bronze.

Call him, but he says he's currently not taking in any more work. He says he will put you on a list.

YES, he's THAT good!!!

He's got a Q-Jet book out, he will sell you a copy, or most major book retailers have one. I bought one at Hastings, around $25.00

The book tells it all. I've read mine over and over, making notes, am hoping to buy some parts soon.

I thought I knew a lot about Q-Jets, I did... now I know HOW they work...
I'm sick of spending hobby dollars on luxury items like gasoline, and groceries...

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Old 01-04-2012, 03:49 PM   #9
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Re: Shaft bushings in Q-jet throttle plate

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The teflon sounds interesting, but wouldn't a thin layer wear out pretty quick, putting you right back where you started?
no different then a large bronze bushing, cept metal to metal will wear quicker.

don't matter how thick said material is, neither is going to get smaller with wear.
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Old 01-04-2012, 07:49 PM   #10
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Re: Shaft bushings in Q-jet throttle plate

Well, lets see, so far, over 600 base plates, of all kinds, some with one heck of a lot of miles on them sinve teflon installation, and, no degradation of the teflon, and, no leaks, but that has only been for the last 35 or so years I have been doing carbs, for myself, and others.

I guess we'll have to give all of them a few more decades before we rush out and say the teflon works, huh!
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Old 01-04-2012, 10:40 PM   #11
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Re: Shaft bushings in Q-jet throttle plate

When I rebuilt my Holley 3310-1 about 20 years ago, the kit I bought (Holley kit) came with the teflon strips for the throttle shaft bores. I haven't checked them in a while, but last I knew they were just fine after 120,000 miles or so.
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Old 01-05-2012, 01:07 AM   #12
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Re: Shaft bushings in Q-jet throttle plate

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When I rebuilt my Holley 3310-1 about 20 years ago, the kit I bought (Holley kit) came with the teflon strips for the throttle shaft bores. I haven't checked them in a while, but last I knew they were just fine after 120,000 miles or so.
Those strips come in the kit because certain Holley shafts have a recess on the shaft itself that the teflon strip goes into. If you have the more standard shaft, the strips will do you no good because there is no clearance for them. You would have to enlarge the bore in the base plate.
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Old 01-05-2012, 11:56 AM   #13
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Re: Shaft bushings in Q-jet throttle plate

Those strips in the Holley kits are there to be added, by real world carb techs that know Holley service procedures, because MOST 4 bbl Holley carbs came with front teflon strips, but didn't have them installed on the SECONDARY shaft from the factory. The secs shafts were cut, but, not bushed. The rational opn that was, primary shafts are constantly in rotation, secfondaries aren't, so, less wear on the secs shafts, more wear, needing bushings on the primaries.

Lets not get out of perspective here, folks, the main reason to bush the shafts is to reduce the air leaks past worn shafts. Bronze/solid materinal bushings still need clearance, so, they only reduce an air leak. Teflon is a lot better to reduce even more, the clearance on cab shafts, thereby further reducing air leaks and binding at those shaft-base junctions. There are the not so great ways carb guru's use, the solid materials/clearance bushings, and, the way Holley does it, that method YOU can do for yourself, with simple hand tools, a very small number of specialty tools, like a drill press and drill bits, scissors, and a little teflon sheet, and ingenuity/effort, in your OWN GARAGE, if you are mechanically inclined.

Choice on which method works for YOU, is....all YOURS.
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Old 01-05-2012, 08:50 PM   #14
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Re: Shaft bushings in Q-jet throttle plate

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Originally Posted by HEI451 View Post
Those strips in the Holley kits are there to be added, by real world carb techs that know Holley service procedures, because MOST 4 bbl Holley carbs came with front teflon strips, but didn't have them installed on the SECONDARY shaft from the factory.
Man.....this is just not accurate. I had to really hunt in my shop to find the correct throttle shaft that is cut for these teflon bushings. Let's just say I have one or two shafts laying around. I guess I should back up a minute. That would depend on what you normally have your hands on. I do very little vacuum secondary work. It's mostly double pumpers. Below are 2 shafts. One is correctly cut for the bushings that come in the rebuild kit and measure at .3350 in the recessed area. The other shaft is a double pumper and the recessed area is .3555. The .02 is the space needed for the strip to work. As you can see, even the center part is cut for the strip. You will NEVER see a double pumper with that recessed area. Actually, you will NEVER see a double pumper with the strips. The reason why Capt used them was because the carb was a 3310 variation and those carbs do use them which is why they are in the kits.

I'm stating this because I don't want some mechanically minded person trying to make them work and getting frustrated if the shaft is not cut, and you have a zero chance if it's a double pumper. Now with that said, I have use the teflon strips on double pumpers and it is tricky. You really have to profile down the thickness of the new strip to almost paper thin for it to work. It's also hard to get the strip in straight because there are not really any "walls" to hold the strip in place like the other shaft.

The old strips you see actually cam off that shaft with was on the REAR of an 1850 600 vacuum carb.
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Still getting loose (carb test)

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