This was a great chance to see some of the lesser-know makes and models. While there was plenty of Detroit muscle around, some of the highlights were historical gems like the stalwart General Motors Truck, the luxuriant Locomobile, the Harley Earl finned masterpiece ’48 Cadillac and many more that helped make the 20th century American car geist.

For working machines, patches, repairs and parts change-outs make the notion of “original” a tricky concept.  Suffice to say, this 1936 General Motors Truck (we call ‘em GMC now) isn’t the same as the day it rolled off the line in the year the Hoover Dam was completed, though it wouldn’t have been too far out of place.

Next to the $550 Ford, the 1913 Model 38 Locomobile at $4300 was very expensive indeed. Even so, this was the smallest, cheapest Locomobile that year. It featured a 477 cubic inch six of 43.8 horsepower, electric horn and electric lights. The particular car shown is thought to be the first car in Alberta equipped with these electric features. It’s been restored, but the leather upholstery is original.

Harley Earl, head of the GM Design Studio, ruminated on the tailfins of the P-38 fighter until new designs could be produced after the war. His vision was borne out in the 1948 Cadillac, the first of a dozen-odd years of finned wonders.

We’ve got a bunch more pictures from this show here. Besides the static displays there were various moving vehicles to see. One of my favorite displays were these old-timers – a couple of Model T’s and a Massey-Harris:

More information:

Locomobile Vintage Print Ads

1948 Cadillac Brochure

BDR 529. That’s the license plate of the Blues Brother’s (nearly) indestructible 1974 Dodge Monaco, the Bluesmobile, which starred in the 1980 Blues Brothers film. As Elwood said to Jake:

It’s got a cop motor, a 440-cubic-inch plant. It’s got cop tires, cop suspension, cop shocks. It’s a model made before catalytic converters so it’ll run good on regular gas.

We spotted the real thing recently in Revelstoke, British Columbia. Well, maybe it wasn’t the actual car from the movie, but it was a real cop car with all the right stuff including the police ‘Pursuit Vehicle’ badge.

Pursuit Vehicle badge

More than just a replica, this car looked like it might have chased down a few perps in it’s day, judging from the original equipment inside, including the SCMODS (State County Municipal Offender Data System) display:

Note also the 140 mph speedometer. More info on 74 Monaco cop cars is here.

Best of all, the Blues Brothers were there for the car show.  Well, almost… they were a really cool tribute act by the name of Blues Brothers Too. Check them out live at the car show:

At The Old Car Manual Project, we don’t sell manuals.  Everything is available to view or download for free.

All of our material is sourced from original scans that we’ve done ourselves or that have been contributed.

One place where good quality downloadable manuals can be purchased (in case you can’t find them on our site) is www.oldcarshopmanuals.com which has pdf ebook format manuals for General Motors products from the thirties to the early seventies, including Buick, Cadillac, Chevrolet cars and trucks, Corvair, some Corvette, Oldsmobile and Pontiac.

Another place, which also has some pdf versions of manuals on our site, plus other materials is www.carmanualsource.com.

Frédéric wrote to us from Dijon, France about his 1936 Buick:

Here are some pictures of my Buick8 of 1936.
It is being restored, but there are very few mechanical parts in France!
It was commissioned by the French army before WW2. In 1940, the Germans would have captured this car. In 1944, the U.S. military recovered the car and given back to the French army in 1946 … !
The speedometer is in kilometers / hour and not miles / hours.
There are currently only 5 models in Europe. I am looking for sponsors to help me restore this lovely car!

It’s a fascinating bit of history on wheels.  If you would like to contact Fred, please drop us a line and we’ll pass the message along. Click on any of the pictures for a full-resolution view.

The Old Car Manual Project has the 1936 Buick brochure here and some 1936 Buick ads here.

At the risk of becoming overly repetitive, I’ll deal with another common carburetor problem.

Typical inquiry: “My Rochester 2GC runs too rich; I suspect the jets have been changed to a larger size.”

This does happen from time to time.  If your carburetor looks like it has missing pieces or has otherwise been modified, there is a good chance that someone has monkeyed with the internals.

Years ago, carb rebuilders would mostly find that 4-barrels had been messed with – QJets, Holleys and so on.

In recent years, since 2 barrel carbs have become socially acceptable, especially in the form of Tri-Powers and other multi-carb set ups, we in the carb business have found more and more “funny” Rochester 2 bbls in circulation.

What to do?

Go to our website with the Rochester carburetor manual: www.newagemetal.com

Here you can look up the specifications for your 1932-1979-ish Rocky carb.  For example, if you had a ‘71 Chevelle, you would go here: http://newagemetal.com/pages/Chevrolet/71/index.htm.

You’ll find scanned pages from the manual with part numbers listed against carb numbers.  If you want to know what jet is correct for your ‘71 Chevelle with a 7041114 carburetor, you would find (http://newagemetal.com/pages/Chevrolet/71/pages/63-69Chevy0112_jpg.htm) that the part number for the jet is 7002658.  The last two digits of the jet part number are the size in thousandths of an inch.

From the factory, the installed jets varied a bit for a variety of reasons. For the most part, 2Jet carbs should be within 1 or 2 thousandths of the size in the manual. Sometimes there were mid-year changes in calibration that weren’t recorded in the published manual, and in some cases it had to do with the nominal size and flow.

Rochester jets are calibrated against a standard jet.  In other words, there is a master jet with an orifice of exactly 58 thousandths to which every other jet is compared. The idea is that every jet labelled as ‘58′ will flow the same as the master jet.  This is why you might measure the hole in a ‘58′ jet and find that it’s smaller or larger.  The ‘58′ refers to the nominal flow, not the size.

Once in a while a jet with a different marked size would get installed in place of the nominal jet.  In other words, you might find a ‘60′ where you  expect a ‘58′ but that might be because the ‘60′ really flowed ‘58′.  Follow me?

In any case, if you have a single Rochester 2-Jet with a reasonable jet size and it runs too rich, you should check the following:

1) Ignition.  Always blame the carburetor last.  There is more on this here.

Check the timing.  If you have a Chevy engine with a harmonic balancer, be aware that the timing mark on the balancer may not be accurate.  As the rubber ring in the balancer ages, the outside hub will mover (“precess”, technically) so that setting the timing with a light gives you retarded timing. I’ve seen these be out by 20 degrees!

If you have points, check the dwell.  This should be 29-31 degrees on a V-8.  Also, check the play in the distributor shaft.  If it’s noticeable, you won’t get good ignition.

At this point, most folks these days go out and buy a new electronic distributor.  It’s not necessary, though, as all you need to do is rebuild the distributor with new bushings.

2) Vacuum.  A vacuum gauge is mandatory when working on old iron.  If your stock Chevy small block doesn’t pull close to 18″ of steady vacuum, you have a problem.  This is a subject for another long post!

3) Carburetor stuff.  If the jets are the right size and it still runs too rich there are a few more things to check on a 2G.

- float: on all carbs, a sinking float will cause flooding.  If the float is brass, shake the float to check for gas sloshing around inside.  If that’s the case, get a new one. If it’s a plastic float, replace it with a brass one.  The black plastic (nitrophyl) floats last 10-20 years and then are done.

-needle/seat: if the needle shows a scoring line where it fits into the seat, get a carb kit.

-power valve: rarely, the 2G power valve will leak.  If your power valve looks like it’s been butchered with a dull screwdriver, you may want to get a new one.  These are not part of a carb kit.  You can order them at here.

-accelerator pump check ball: if the accelerator pump discharge check ball is missing, or if it doesn’t seat, the 2G carb will sometimes siphon fuel through the accelerator pump circuit.  This ball is under the venturi cluster.

-wrong throttle body gasket: in most 2G’s from the late 50’s to the mid 60’s the gasket between the float bowl and the throttle body should have vent slots. Without these the carb might have a hot-soak flooding condition.  Note that marine carbs never use these.

I think that pretty much covers it for single carb applications.

From time to time I’ll try to answer a few of these here.

Cristobal from Chile wrote:

I have a oldsmobile omega 78′ with a V6 buick 231 engine, and a
rochester carburator 2GE model. I am trying to find the difference
between the 2GE and the 2G, 2GC and 2GV carburators, but i can’t find
it. The only difference that i could see, is that my carburetor uses a
solenoid and no automatic choke. Could you respond this doubt?

I sent you a pictures of the carburetor.

Good question!  This is the source of some confusion among Rochester owners.

The answer:

• 2G is the model of the basic Rochester Two-Jet carburetor with a manual choke (cable operated)
• 2GV is the same carb with an automatic choke when the choke coil is mounted on the manifold (a so-called remote choke)
• 2GC is this carb  with an automatic choke where the choke thermostat is attached to the carb and is heated with hot air from a tube coming from the manifold (heated by exhaust gas)
• 2GE is an automatic choke carb with the choke being heated electrically

There is more information and illustrations of the 2G family here. The complete Rochester manual up to 1979 is here.

What about the carb in the picture from Chile?  It’s hard to tell – I would guess it’s a 2GE with a missing choke housing, since there is no choke assembly visible.  In fact, in ‘78, at least in US production, GM cars used only 2GC or 2GE carbs.

The arrow in this picture is pointing to the 2GC choke housing.

In a 2GE carb, the only difference is that the housing has an electrical connector and there is no pipe fitting (for hot air) at the front.

Regarding the solenoid in the Omega carburetor above – this is an idle speed control (or idle stop solenoid), usually used to speed up the idle on air conditioned cars or for emission control purposes.  It’s not related to the operation of the choke.

In some cases, especially on smaller engines, the idle is set with the idle solenoid energized.  When the engine shuts down, the solenoid retracts allowing the throttle to close fully.  This prevents run-on when a high idle speed is required.

Back in July, the annual Lacombe Show and Shine was on and there were some really interesting vehicles as always.

This one is a 1955 Bel Air (Canadian production), equipped with a dual Fenton intake and headers.  Our shop built a pair of Rochester model B carbs for the owner.  It took a lot of tuning to get these to run right – I think the he may still be tweaking these.

With this set up there is less manifold vacuum at part throttle, so you need to shorten the power piston springs to keep the carbs from getting into the power mixture under light load.  Also, the jets need to be on the large side because of a weaker vacuum signal (due to the larger venturi area).  As well, the carbs should be synchronized.  Finally, you have to consider that Model B carbs came with various sizes of power channel restriction – essentially a fixed jet that determines how much additional fuel flows when the power system is engaged.

Another one I really got a kick out of was the GMC COE truck.  These are getting as rare as hen’s teeth.  You sometimes see Chevrolet Cab-Over-Engine trucks, but not so many GMC’s, at least not here in the Great White North.

Notably, GMC trucks like this usually used a Zenith updraft carburetor while the Chevy versions used a Carter BB updraft.  Of course the reason for the updraft carburetor was because of clearance around the engine.  This is why these continued to use updraft carbs until 1962, while GM cars had gone downdraft by 1932.

Elsewhere on the site we have some print ads for the ‘51 Studebakers, both cars and trucks. Also from Ron is a 1951 Studebaker booklet with test results from Mechanix Illustrated.

It covers the classic ways of tuning up the cars using simple tools and delves into the details of the typical Carter, Stromberg and Zenith one and two barrel carburetors of the day.

Some of the topics include:

• How to use a vacuum gauge, including for setting ignition timing
• Use of a compression gauge
• Testing the ignition circuit

Also, it has practical advice on setting up Buick Compound Carburetion, the quirky dual two-barrel set up used on the Buick straight-eight.

Find the full text here: http://carbkitsource.com/carbs/tech/articles/TuneUp/CarburetorTuneUp01.html