The Old Car Blog

Just outside Dog Rump Creek is my shop (The Carburetor Doctor) in sunny Stony Plain, Alberta.  I thought you might enjoy the view from my front door on this beautiful spring day, shortly after opening up this morning.

I came across a real gem at the Powerama swap meet today in sunny, warm Edmonton, Alberta, Canada. There is an outfit from Calgary that is producing licensed, poster sized versions of classic GM, AMC and Chrysler ads. These aren’t mere blow ups of magazine ads, but are lovingly restored and reworked to look great at 24″ by 36″. Stop by www.classicautoimages.com to browse their store.

Now in case you’re wondering, this isn’t a paid plug - I was truly impressed with the great idea that these guys have and the work they’ve done on these images. Of course, if they want to support The Old Car Manual Project by taking out a small ad, I won’t be offended.
As for the truthiness of my remark on Edmonton weather… well… while not actually sunny, it was only a few degrees below freezing with a little blowing snow. Could be worse, I say! After all, I didn’t see a single polar bear all day!

Here’s nearly three thousand pages of specifications, parts lists and service procedures for every Rochester carburetor from 1932 to 1980:

It’s a little hard to navigate, but within this collection are all the specs and part numbers for every Rochester carb for five decades, including all the muscle car era. Now you can settle that argument over the correct carb number for the ‘69 W-31 Olds you just picked up!

(Hint: the answer is here)

Before refinishing a carburetor, you’ve got to get it clean. In my shop (The Carburetor Doctor), I have several methods for cleaning and prepping, depending on what we’re dealing with. Let’s say you have a typical, reasonable condition, not-seized muscle car Holley or Rochester Quadrajet. The bodies of these carbs are green chromate-finished zinc; the throttle bodies are natural aluminum (see my previous post on this subject). In our shop we would remove the throttle plates, choke plate and all shafts and fittings before cleaning. More on removing shafts in a later post.

For your own sake, remember that I’m presenting this information only for reference purposes - you must use your own judgment and be sure that you are aware of any hazards present if you’re going to try any of these operations. Some of the chemicals and procedures used below are dangerous and are for professional use only. ‘Nuff said.

Here is a typical cleaning sequence for a fully disassembled carb:

1. Degrease: I use lacquer thinner, gunwash grade. This stuff is flammable and you don’t want to breath the vapors. Use caution. An overnight soak followed by a thorough brush cleaning is sufficient. Use a wood-handled bristle brush, not a synthetic one (they will fall apart). Work outside or in a fume hood.You can also use commercial carb cleaner. If your cleaner contains dichloromethane or tetracholoroethylene (2-layer type cleaner) DO NOT soak aluminum parts any longer than necessary. They will corrode if left overnight. Many bike carbs and SU’s have been ruined this way.
2. Air dry thoroughly and blow out with air. Wear eye protection.
3. Acid soak. I use a commercial metal cleaner which consists of mainly phosphoric acid and detergent. Soak for a couple of minutes until fizzing is evident and ‘white rust’ is removed. Don’t overdo it or your carb will be destroyed! If you don’t have this cleaner or you aren’t restoring the chromate finish later, you can use vinegar instead. It won’t attack the finish as fast, but will remove crud with a bit of brushing. Again, don’t overdo it.
4. Rinse thoroughly in hot running water.
5. Air dry and blow out very thoroughly. The carb must be bone dry for the next step. Bake in a 200 F oven for half an hour if unsure.
6. Glass bead: One way to get the carb down to bare, shiny white metal is to bead blast using very fine (#10) beads. Use clean beads and do the carb inside and out until it’s a shiny silver color. Use a blast cabinet and wear breathing protection.
7. Blow out thoroughly with a high pressure blow gun - a ’safety gun’ isn’t powerful enough. Wear full-face and eye protection and hearing protection and be thorough.
8. Acid rinse: Using the same type of phosphoric acid/detergent as above, immerse the zinc parts of the carb only for about 30s or so in a fresh, clean batch of metal cleaner. Aluminum parts don’t need this step.
9. Rinse very thoroughly in tepid running water (body temperature) until all signs of fizzing are gone.
10. Immerse in the chromate solution for the appropriate time (see below). This is the trickiest part, since it depends on the concentration of the solution, the temperature and on the type of carb - not all zinc alloys are the same. I will say more about the chromate solution below, but for now, suffice to say that it’s dangerous, expensive and tricky to use. You can immerse both zinc and aluminum parts for corrosion protection, though only the zinc parts will pick up the green colour.
11. Rinse thoroughly in COLD running water until all traces of coloured chromate solution are gone. Hot water will wreck the finish at this point.
12. Air dry.

If everything is done right, the zinc parts of the carb will be an iridescent olive-green colour, just like new. Be warned though, it’s tough to get it right.

If you’re doing a backyard resto, you can stop after step 5 or 9 depending on your equipment. Usually, it’s best not to remove the finish (step 6) unless you’re going to redo the chromate. So, I would stop after the vinegar rinse if that’s the case. Now you can invest in a can of Eastwood carb finish and spray the carb. It’ll look OK from a distance, and even better when the hood is closed.

About the chromate solution

This consists mainly of chromium (VI) oxide (aka chromium trioxide) dissolved in water with a bit of nitric acid added. These are dangerous chemicals in untrained hands!

If you want to try, you can obtain the chromate mix (solid) from Atotech. Minimum quantity is 100 lbs - enough for a lifetime. Follow the mixing directions and prepare a solution of about 30 g / L of the solid mix in water. Add about 1 mL / L of concentrated nitric acid.

With this solution, it takes a 10 s soak for a typical Holley or Rochester carb to form the chromate coating, OEM style. The picture above shows a 1969 Buick GS400 Quadrajet that was refinished using this procedure.
As I said, this isn’t really practical or advisable for most people.

Next time, I’ll go over how the other finishes are done.

If you’ve been to oldcarbrochures.com or tocmp.com in the last few days you’ve either had slow access, or none at all. This is because we moved the site to a new web host in the hopes of having better service, and ended up with hardly any access at all. Bottom line with web hosting is caveat emptor.

In fairness, the site had become very popular and very large (25,000+ brochure pictures, 40,000+ pages, 400,000 visitors per month). Accordingly, it seems that it’s time to move to the next level, which is why we’re moving to a dedicated server (more expensive still!).

This will take a while, so please bear with us and stay tuned for the next incarnation of Old Iron Online!

I have just acquired a 1952 Chevrolet 3800 extra long bed (9 ft) 137 inch wheelbase truck.

Does anyone have any reliable parts sources for specific parts for this model. Apart from the engine, cab sheet metal and rear fenders, it seems as though most parts are specific to this model.

Any and all information would be appreciated. Also I would love to be in contact with any one else out there restoring the same or similar model truck.

Now that the new oldcarbrochures.com site has been up for a month or so, it has accumulated hundreds of brochures for American, European, Asian, Canadian and other cars and trucks - about 24,000 images so far!

If you have old brochures that you would like to share with the world, you can register at the site and upload your scans yourself.

Eventually, we would like to build a comprehensive library of car literature up to 1987 (our cut off for ‘old’).

One of my recent favorites is this fabulous 1929 Nash brochure

Here’s a wonderful postcard I received from Mano Forsman, a major Old Car Guy and avowed ‘53 Cad lover from Sweden (click to enlarge):

Being in the carburetor business, I get asked about refinishing carburetors quite often.

I have learned that there are a lot of misconceptions out there about the finishes on carburetor parts, so I’ll take a stab at clearing things up a bit.

There are three main materials of which carburetors are made: cast iron, zinc and aluminum. Starting in the 30’s, cast iron started to be replaced by zinc and in the late 50’s, aluminum replaced a lot (but not all) zinc.

In most cases, cast iron is finished in black oxide though it’s sometimes painted black. Carter recommended a special black carburetor paint when rebuilding a carb. Thus, while carbs like the W-1 Carter were originally black oxide finished cast iron, many of them are now - correctly - a semi-gloss black.

Rochester carbs also used cast iron in the throttle body section. This part was always black oxide and there was no factory paint recommendation.

The most well-known carburetor material is olive-green colored zinc. Zinc itself is a bright silvery metal that reacts with air and water to make a powdery white material often called ‘white rust’ . To prevent this, carburetor parts are treated in the factory with a chromic acid solution, which forms a thin layer of ‘zinc chromate’ on the surface of the metal. This very effectively protects the metal underneath from being damaged by water or air. This is why carburetors are usually green!

The last finish is natural aluminum, which is found on carbs like the Carter AFB (Aluminum Four Barrel) and Ford 2100/2150.

The Carter WCFB carburetor used all three materials: cast iron in the throttle body, zinc in the float bowl and aluminum in the air horn.

Next time, I’ll write about how to restore some of these finishes.

The new classified ad site and online swap for The Old Car Manual Project is now up and running at classifieds.dogrumpcreek.com. This is a place where you can list your old car parts, literature and even cars, for free! It’s hosted by Dog Rump Creek Auto (another one of my projects) and is intended to provide a medium for finding and selling parts without the hassle and expense of sites like ebay, or having do dig through mountains of unrelated junk on general purpose classified sites.

Have a look, try it and let me know what you think.