Carburetor restore

[Mudbone]

I think this subject has been covered before but I couldn’t fine it. What is the best way to preserve the new carb look after rebuilding it? Paint, clear coat? Mud

[carbking]

Obviously, the best method would be to place the carburetor on a shelf in a climatically controlled environment. Assuming it was restored, the finish should last 20 or so years.

Oh, you wanted to actually use it? Put it on the engine, and periodically use a toothbrush and some clean gasoline to remove any stains. Again, assuming restoration, the finish should last 20 or so years.

For original finish, it is carburetor cleaner that removes the finish.

Jon.

[Mudbone]

Obviously, the best method would be to place the carburetor on a shelf in a climatically controlled environment. Assuming it was restored, the finish should last 20 or so years.

Oh, you wanted to actually use it? Put it on the engine, and periodically use a toothbrush and some clean gasoline to remove any stains. Again, assuming restoration, the finish should last 20 or so years.

For original finish, it is carburetor cleaner that removes the finish.

Jon.

Ok, you say "For original finish, it is carburetor cleaner that removes the finish." Do you mean once you cleaned it in carb cleaner the original finish is gone? Were they coated from the factory? Thanks, Mud

[Guest shadetree77]

Don't know how well it works as I've never tried it but how about this followed by a hi-temp clear coat?

Carb Renew 2

[NTX5467]

Seems like Eastwood had a "cad-colored" coating for use on carburetors, power brake boosters, etc? From some of the earlier postings of using that product, it seems that "discretion is the better part of valour", as many probably try to "make sure it's on there" rather than just a light coat, resulting in a more-orange tint rather than a "bright cad". Otherwise, you get the gray "base color" of the carburetor's metal.

I suspect that if you're going to use some sort of "paint", it would certainly need to be "fuel resistant" in capabilities, including "alcohol resistant", all things considered.

Perhaps the "cad coating" was more for corrosion resistance than anything else? IF I was seeing a car at a car show, I would "expect" the "plain look" as you would know the carb had had to have been rebuilt at some point in its life. If I saw a similar car with "too much cad", then I'd KNOW it had been rebuilt and the owner was a little too zealous in trying to replicate the original factory coating . . . which seemed to evaporate with age anyway.

Your judgment call . . .

NTX5467

[carbking]

There is sufficient information on this subject to do a book, if one had time to do a book. But in a nutshell:

Zinc alloy was/is used by many different manufacturers of carburetors for castings.

Zinc alloy is normally some shade of gray in color.

Most zinc alloy was originally coated to protect the alloy from oxidation. This protection was a chemical etching achieved by cold dipping the casting into a combination of nitric, sulphuric, and chromic acids mixed in fairly precise amounts. The greenish, goldish color on new zinc alloy is the residue from this chemical etching.

Dipping the castings in carburetor cleaner removes this coating, which then subjects the metal to oxidation and failure. Generally, the zinc alloy, after being subjected to carburetor cleaner, again becomes some shade of gray.

When carburetors are "restored", original finishes are reapplied to all surfaces.

As different companies used different zinc alloy mixes, the "color" of the castings, both without the chromate coating and with the chromate coating will vary.

The above just scratches the surface, as many different finishes were used as original, depending on the company and the application.

Jon.

[Mudbone]

Ok, so does anyone have a photo of what a 55 carb should look like as if it came off the assembly line? Silver? Gold tint? Main body only? Etc Etc. Mud

[carbking]

OK, for 1955

Buick might have used two different manufacturers of 4-barrel carburetors, Carter or Rochester.

If Rochester:

Zinc alloy castings (choke housing, airhorn, bowl, venture clusters) - zinc chromate

Here is a link to a very faded new old stock Rochester casting from a single barrel. One can see traces of the chromate (greenish-goldish color) residue, especially on the right side of the picture: http://www.thecarburetorshop.com/Rochestersealingridge.jpg

Cast iron throttle body - natural (rust brown, actually it was Parkerized [gray] but this color did not last long).

Steel pieces - yellow zinc (the yellow conversion would fade leaving the appearance of white zinc after several years)

Screws - YELLOW ZINC (this finish was changed to black oxide about 1956, but you asked about 1955)

Tag - I don't remember, but think they were aluminum

If it were Carter:

Zinc alloy castings (choke housing, pump jet housing, and bowl) - same zinc chromate as used by Rochester.

Airhorn (aluminum - natural)

Cast iron throttle body - painted with "Carter Special Castiron Paint (this paint was close to a 60 percent gloss).

Steel pieces (including screws). Carter was located across the street from Howard Crown Plating. As steel items came in from the stampings plant, they were hustled across to street to Crown, where they were electroplated with one of four different finishes (whatever Crown was running that day). These finishes were: zinc, either white or yellow; or cadmium, either white or yellow. I have some new old stock Carter carburetors that exhibit all four finishes. As Crown ran more white zinc (maybe 60~70 percent), the probability would be high that most, maybe all, of the steel pieces would be white zinc.

Tag - brass, or steel with brass electroplate.

Jon.

[old-tank]

Jon as usual is right on target. For what it's worth, untouched Rochesters I have seen are very heavy and definite on the gold for the cast parts; The Carters seem to have faded gold or a rainbow effect on the bowl only.

(You cannot see much of it anyhow under a dark hood, with the air cleaner and muffler installed...it's going to be a driver isn't it?)

Willie

[JohnD1956]

I don't know about not seeing much of it Willie, look at your own signature picture? You gotta raise the hood at the National to be in the Gold Senior Driven Club.

[old-tank]

I don't know about not seeing much of it Willie, look at your own signature picture? You gotta raise the hood at the National to be in the Gold Senior Driven Club.

John

That picture was taken with sun at the back of the hood in addition to flash. I have never seen points deducted for improper finish on the carb. The one in the picture was a crusty old carb that was lightly glass beaded and clear coated --- there is no trace of gold on the bowl. By the way it runs good :)Willie

[Mudbone]

I pulled the carb out of the cleaner and this is what they look like. I think a light coat of Eastwood’s bare metal satin clear and run it. Mud

[Dwight Romberger]

Check out Robert's idea-Carb Renew II. Eastwood has two versions in rattle cans: Bronze Carb Renew II and Silver Carb Renew II

[Guest shadetree77]

Mud, is that Eastwood clear heat proof? If not I'd recommend VHT Engine Enamel. They can be bought at almost any auto parts store and they do make a clear coat.

[carbking]

Please remember that the ORIGINAL purpose of the ORIGINAL finish (in most cases, there are exceptions) was to PROTECT the metal from oxidation, NOT to make it look pretty.

Jon.

[Mudbone]

Please remember that the ORIGINAL purpose of the ORIGINAL finish (in most cases, there are exceptions) was to PROTECT the metal from oxidation, NOT to make it look pretty.

Jon.

But I like pretty, Oh I forgot, it's just a driver. Mud

[buick840]

Just wondering how much difference, if any, there is between a 55 Carter 4 barrel carb off a 322 compared to one of a 54 322?

Interchangeable?

Performance the same?

[old-tank]

Brian

The 54 version is taller, so you would not be able to use the stock air cleaner/muffler without hood interference...it also has smaller bores, so performance will probably suffer.

Willie

[buick5563]

Darnit.

Willie beat me to it again!

[NTX5467]

(NO "on time" points for you, today!)

[buick840]

Brian

The 54 version is taller, so you would not be able to use the stock air cleaner/muffler without hood interference...it also has smaller bores, so performance will probably suffer.

Willie

Rats!!

There is a 54 Carb and manifold for sale locally but not much use to me if it won't do the job.

Guess I'll be posting another wanted advert for a good 4 barrel for the 322 I'm going to swap into my 55 special.

What about a 56 carb? I might know where there is one of those

Better luck next time Mike..........the early Texan catches the praise;)

Thanks Willie.

Edited July 7, 2013 by buick840 (see edit history)

[carbking]

But I like pretty, Oh I forgot, it's just a driver. Mud

Nothing wrong with "pretty" on a driver. The point of my post was that protection was generally the goal. And my belief is that protection should be done first, "pretty" second.

One of the "pretty for no apparent reason" carburetors is the Carter YH used on the turbocharged Corvair. The standard chromate was done to the body, but then the body was additionally painted black, and all the steel pieces as well as the tag were chrome-plate. WHY???

Consider:

(1) The carb on the turbo-Corvair is almost buried from view.

(2) The carb on the Cadillacs of the same year got standard finish.

(3) The carb on the supercharged Studebakers got standard finish.

(4) ALL other YH Carter carbs got the standard finish.

So why did the turbo-Corvair carb get the "pretty" treatment?

Jon.

[Mudbone]

Thanks for all the info guys. The nice thing about the carburetor is that if you don’t like it, pull if off and change it! I will be posting the completed picks on the “Me And My Buick” section. Mud

[60FlatTop]

There is a carb cosmetic treatment that can make a real good conversation piece. Here's the story:

For a few years in the 1990's my daily driver was a 1956 Olds Holiday 4 door hardtop with a Super 88 engine and no Super badges. The car had a 4GC that I converted to electric choke.

I was never able to revolve a lean stumble problem. When the engine was off I had a good shot of fuel from the accelerator pump. When it was running, no fuel. My final thoughts were that some porosity existed in the casting around the accelerator sump that connected to a vacuum passage and sucked it dry while running. Anyway, I could live with it and eventually sold the car.

As part of the troubleshooting I took the car to Tom Toal who was a Rochester Products engineer. He started with them in 1962 on the tail end of 4GC production and is the guy who designed those extra long screws in the rear throats of the QuadraJets. He did that so they wouldn't fall in. I spent about 3 hours with him assembling and disassembling my carb and trying to de-bug it. He charged me $90 plus the kit. I would gladly spend that 10 more times just to hear his stories about his career at GM.

One story was about the Gold Carburetors. Rochester would send out test carbs to the various GM divisions and the division engineers would tweak the settings for the best performance with an engine/transmission combination. When they found the exact setup they wanted for production they would send the carbs back with the preferred carb painted gold. That was the standard for a given model. Tom had a few gold painted ones sitting on a shelf in his garage.

Now, if you are the kind of guy who likes to lean on a fender and spread it a little deep, just what color would your carb be?

On the side, Tom was always requested to be taken away for engineering duties when Ed Cole was in Rochester, New York. Tom was his preferred driver. That gave Tom a whole bunch of historical stories from Ed that went back into the 1930's. I am really lucky to have had those few hours with Tom.

How did we do? We didn't fix it. At one frustrating point Tom even asked me if I was a plant from someone trying to pull a joke on him. I wonder if there will be a gold carb at the Nationals.

Bernie

Edited July 7, 2013 by 60FlatTop (see edit history)

[carbking]

Great story! I must remember to ask Tom about his driving next time we speak.

As to your lean hesitation:

Fuel volatility started increasing in the 1970's, by the late 1980's it was ridiculous (although less than it is now)!

Your Rochester 4-Jet (4-GC) was designed to work with a volatility of maybe 5.5~7 on the Reid Vapor Pressure Scale. Even at this volatility, Rochester (and others) had an issue with fuel percolating in the pump well. The vented accelerator pump was designed (by Stromberg, in the 1940's) to allow the percolation air bubbles to go through the pump vent, thereby relieving pressure in the pump cylinder under the pump. Too much pressure in this area would knock the pump discharge valve off of its seat, causing the fuel in the pump well to slowly diminish in volume until it was empty.

Carter had the same problem with the AFB carbs, but solved it by changing the mass of the pump discharge valve (Carter mostly used a pointed piece of square brass).

Double pumping the footfeed will recharge the pump well, and eliminate the hesitation with the second pump. Other than that, one might try having the discharge check ball for the Rochester made from a material more dense (heavier) than steel.

Jon.

[60FlatTop]

Tom will remember the Olds we blew the muffler off. And we beat the check ball to death. I solved the problem. There are lots of nice cars with AFB's and Q-Jets.

The best story was Ed Cole's early cold start testing in northern Wisconsin and the chickens. Get him to tell that one.

His other memorable advice was that carburetor design is not engineering. It is art. It has been close to 20 years since I spent those few hours and that advice has helped me solve some apparently untenable engineering problems. Glad to here he's still kicking.

Bernie