Recent Posts

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21
Quadrajet Carb Talk and Tips / Re: Ethanol free fuel
« Last post by Cliff Ruggles on February 04, 2025, 05:46:36 AM »
Nothing really wrong with ethanol blended fuels as far as engine performance is concerned. 

It does soak up some water in a vented system, so plan accordingly.

It will also swell up and destroy most accl pump seals being supplied today.  My accl pumps and seals are impervious to it and the only ones out there with a lifetime warranty in any type of fuel.

Below is a pic of what happens to the "blue" or "black" pump seals from your kit if you didn't buy it here.

My seal is on the right.  These pics were taken during a class I put on couple of summers ago in front of many witnesses.  At the beginning of the class I put all three seals in pump fuel at 10 percent ethanol.

A couple hours into the class we took a break and this is the result.  Swollen pump seals result in difficult or "no-start" scenarios after the carb sits for a few days, and eventually they either roll off the pump or rip/tear.  Between fuel evaporation, drain back and none getting past the seal to fill the pump well on the upstroke of the pump cold starts are a real issue.

This is almost ALWAYS miss-diagnosed as a bottom plug leaking issue and starts a chain of events where the owner starts all sorts of needless repairs to bottom plugs that were NOT leaking in the first place.....FWIW.....
22
Quadrajet Carb Talk and Tips / Re: 17057231 specs?
« Last post by Cliff Ruggles on February 04, 2025, 05:37:19 AM »
Primary POE is just that.  It ADDS fuel with quick throttle movements and when pressure differential is greater above and below the primary throttle plates. 

It wasn't used on 99 percent of the Q-jets produced and they work fine without it.  I see no need to use it for anything more than it was meant for, really lean set-ups trying to squeak thru the EPA's ever tightening emission standards.

Since most of or all of the emission devices on these engines have been removed or disabled, and most also have engine changes, there is really no reason to use it or any advantages doing so.

Your Caddy carb is a nice unit, but as with any other carb selected it must be set up exactly for the application.  Out of the box it may show a slight advantage to other carbs from that period as the big Caddy engines weren't as efficient as other designs and it delivers more fuel just about everywhere in stock form.........
23
Quadrajet Carb Talk and Tips / Re: Repairing a main well plug leak
« Last post by Cliff Ruggles on February 04, 2025, 03:26:26 AM »
"I couldn't find how you do it in your book, thus the question posted previously"

Bottom plug leak testing and repair is covered at the beginning of Chapter 5 pages 71-72.
24
Quadrajet Carb Talk and Tips / Re: New accelerator pumps, which one?
« Last post by Cliff Ruggles on February 04, 2025, 03:19:59 AM »
The only difference is the accl pumps is the length of the pump.  Same springs, same USA made lifetime warranty seal.

The shorter pump is standard for Marine carburetors.  It was also used in the Edebrock 1910 "850" cfm high performance Q-jet.

                               
25
Quadrajet Carb Talk and Tips / Re: Who is Lars ?
« Last post by GSP7 on February 03, 2025, 10:16:04 AM »
For newby Q-jet learners like me, I found a good article Lars has, explaining Main Air Bleeds MAP, and Idle Air Bleeds IAP, and Idle Fuel Restriction IFR and different year range carbs '60s -'70s-'80

26
Quadrajet Carb Talk and Tips / Re: '66 calibration data
« Last post by novadude on February 03, 2025, 09:59:32 AM »
Thanks.  So in this case, more air would / could be added above the upper IAB via adjustment of the screw?
27
Quadrajet Carb Talk and Tips / Re: 17057231 specs?
« Last post by Cadman-iac on February 03, 2025, 08:37:41 AM »
 Just realized I asked about the wrong carb number. I meant to ask if the 17057231 a good one to use on a 350 SBC?
 Thanks for your help.
28
Quadrajet Carb Talk and Tips / Re: 17057231 specs?
« Last post by Cadman-iac on February 03, 2025, 07:05:29 AM »
 Thanks Kenth,

 That's a little more than what Cliff explained in his book.
 Does that Rochester book give any information on altitude calibration differences, or what might be different between federal and California carbs, or why one would have a pullover system and not the other?
  Is the 17057230 a good carburetor to use on a 350 SBC?
29
Quadrajet Carb Talk and Tips / Re: 17057231 specs?
« Last post by Kenth on February 03, 2025, 12:07:26 AM »
From the Delco/Rochester Manual:

30
Quadrajet Carb Talk and Tips / Re: Ethanol free fuel
« Last post by Cadman-iac on February 02, 2025, 11:58:50 PM »
Depends of the tune-up.

https://www.thecarburetorshop.com/Ethanoluse.htm

 Wow! That's a lot to take in. It sounds like if you use the ethanol-free stuff you can tune like the factory intended, but if you are using the ethanol crap you will have to recalibrate for it.
 Going with the ethanol-free fuel means that you will have to make sure you can get to another station that sells it if you plan on traveling too.

 Thanks for the link, that explains a lot.
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