VCCA Home Forums TECHNICAL - GENERAL Mechanical - Engine, Trans, etc Carburetor Rebuilding kit

Steve - thanks for the tracking number. Will let you know if I find it.
Ray - so a 574S can be made into a 569S? Thanks for the offer on the kits. Will see how things go and contact you if needed.
Thanks to all who responded with info. I took the easy (and expensive) way out and bought a refurbished 569S supposedly properly calibrated and tested by a long established carburetor shop. Some of the details mentioned previously scared me away from getting a kit and doing it myself.

"Ray,

What is the secret sauce to get the plugs, jets, and check valves out? I always have a hard time with that."

Dave, the suggestion I got from JYD is to heat the stuck brass item to a dull red heat with an oxy-acetylene torch with a very small tip then let it cool. I tried that and it has worked every time. That, obviously, has to be done VERY carefully to keep the brass item as solid and not turn it into a liquid.

"Some of the details mentioned previously scared me away from getting a kit and doing it myself."
"Ray - so a 574S can be made into a 569S?"

Bertus, I see that you're selling some W1 carburetors. If you disassemble one of those I think you'll be astonished at how simple they are. There is no need to be intimidated. I made my own 569S and I'm just an amateur, not a pro like Jon, so how hard can it be? Complicated are a Quadrajet or a Thermoquad.

"The calibration at any value of vacuum is the result of the combination of the fuel AND air jets. Thus, looking only at the fuel jet sizes from two different carburetors does not tell the entire story. The air bleeds may also be different.

Carter used metering rod technology beginning in 1929. Thus the effective fuel metering at any vacuum (assuming the RPM is sufficient to be on the main circuit) is the dynamic difference of the AREA of the main metering jet, and the AREA of the rod located in the jet at that value of vacuum."

Jon's explanation is excellent and is in any discussion of how carburetors work like Doug Roe's publication on Rochester carburetors. If one accepts what Jon has explained I don't see how anyone can believe that "One size fits all". Carburetors have tremendous potential to optimize engine performance if they are calibrated exactly for the engine and operating conditions they will be used in. With such a huge range of interchangable metering parts available why would anyone not experiment to find what works best in their application? I've heard from Bonneville salt flat racers that in their experience carburetors produce more horsepower in that setting than fuel injection.

"An issue with the W-1 that can upset the metering is wear in the round hole on the throttle shaft bracket supporting the pump rod, and the pump rod itself. Wear will cause the throttle valve to be too far open for the position of the rod in the jet. This wear should be evaluated at any rebuild, and defective parts repaired/replaced."

Jon, thanks for pointing that out. In my own home amateur carburetor reconditioning efforts I have made a jig that allows me to put a bushing in that out of round hole to restore a correct fit. Also, those float bowl covers are abundant on ebay NOS to solve the same problem..

To me the castings of a carburetor are like my wife's crock pot. She puts in the correct ingredients in the correct proportions and what comes out of that is always delicious. If others believe that the "Just add water" stuff at the supermarket tastes the same we'll just agree to disagree. All of this is irrelevant to owners of trailer queens but vintage vehicles that are actually driven might as well perform at their full potential.

Ray W

Thanks all for the info.

Dave

Ray - the issue with the bowl cover you mention is a different issue, but only with the earlier W-1's. The 569s/574s use a revised bowl cover which eliminated that issue. The issue I was referring to is the steel bracket held on the back side of the throttle shaft with a single screw, and the "L" shaped rod connecting this bracket to the rocker arm at the top.

Jon.

Wow - sure are a lot of different opinions on carbs! Thanks to all for the info - very educational.
Doesn't seem to be a lot of demand for my old carbs so I think I will take one apart as a training exercise.

"Wow - sure are a lot of different opinions on carbs! Thanks to all for the info - very educational."

Yes, the abundance of "opinions" on these car forums, especially VCCA Chat and Stovebolt that seem to rely on single designated "gurus" no matter the subject, is what makes them amusing to read. If you ask Jon, a true carburetor professional, to explain how carburetors work or read Doug Roe's Rochester Carburetors & Emissions Controls you will learn why it's very unlikely that a carburetor specifically intended for one vehicle would also be perfectly jetted for another engine "out of the box".

I think the reliance on single experts on forums has the benefit of being easy and quick but how can these "Experts" know all there is to know, no matter the subject? Obviously they can't.

"Doesn't seem to be a lot of demand for my old carbs so I think I will take one apart as a training exercise."

Taking them apart won't diminish their value because it's probably been done many times before, as long as you reassemble them. When you take them apart don't be surprised to find missing and/or damaged parts. That's typical of those old cores.It's the prices you've put on them Bertus. For a reality check take a peek at W1 carburetors on ebay. Here's one with the flat throttle shaft arm that your '32 needs and at $19 "buy it now" there are no takers:

https://www.ebay.com/itm/VINTAGE-CARTER-W1-CARBURETOR-C-ORIGINAL-CHEVROLET-1930-1936-216-RAT-ROD/223287604102?hash=item33fcfa7386:g:cs8AAOSwI2xbeiEv:rk:51:pf:0

I've got several of them that I probably couldn't even give away because the cost of a USPS Flat Rate shipping box exceeds the value of a common W1 core.

Ray W

Bertus - - What carburetor shop did you buy it at? I'm looking for a 259S a 569S.

Thanks,
Dennis

Hi Dennis:
I bought it from "Carburetor Center" 3207 Peck Road, El Monte California 91731. (626) 448-8907

Bertus - the Carter W series of single barrel carburetor (W-0, W-1, and W-2) were excellent in their day, and are still excellent. They intimidate a few because they can be somewhat challenging to disassemble with out the use of heat.

Like most items produced by humans, they did have some "teething" issues, but by the 1939 Chevrolet (420s) issues had been corrected.

The W series uses a leather (totally impervious to alcohol) accelerator pump, and a mechanical power system. You never have to worry about replacing a fatigued vacuum spring, because the mechanical power system is mechanical.

Over the years, we have put W-1's on lots of different applications (including a V-12 Cadillac) with great success. One just needs to do one's homework as to venturi size, etc. when selecting the carbs. The infinite number of metering rod diameter combinations very precise tuning possible (I realize that having the ability to machine metering rods is an advantage here, but lots of standard rods are available). Carter produced 128 DIFFERENT type W-1 carbs, so often a matter of doing a bit of research. The large maroon Carter books often show up on Ebay for not a lot of money, and are an excellent reference.

Too bad that Carter did not continue the W-2 size (would have been correct for a 235 engine), but they did not.

Take one apart, and learn from the experience (first, print off the service instructions on my website). Pick the grungiest one you have. Once you have it apart, you will have confidence to rebuild the better ones.

One newer issue, definitely NOT the fault of the carburetor, but some of the cheaper aftermarket kits for the 483s and 574s are using the same weak pump cup expansion spring used on the newer Rochester Q-Jets. This spring is too weak, and the accelerator pump with this spring will not function correctly. The correct pump spring is the same size as the spring on the rebuildable earlier pumps. Issues caused by using incorrect parts cannot be charged to the carburetor design.

Jon.

Bertus.....Wow, thanks for response. I live in Apple Valley. I will ride my Harley up there and check them out.

Dennis