Sunday, May 19, 2024

What We Have Here is a failure to Carburete...


My brother owns a 1951 Studebaker Champion.  A nice one.  It should be, he spent $16,000 one year having it professionally restored.  

The 51 was the second and last year of the famed "Bullet Nose" Studebakers.  Intended to mimic the front end of a jet fighter, I thought they did so better than the tail fins that came out a few years later mimicked the back.  The 1950 was, if I recall, one of the hottest selling Studebakers ever.  The 51 wasn't nearly such a success.  For 1952, the whole bullet nose theme was dropped for a more conventional look albeit on the same "which way is it going?" body.

                                                               Not my brother's Car.  Just one like it.

Also for 1951, the big Studebakers, the Commander and Land Cruiser, swapped their big L Head six cylinder engines for a brand new overhead valve V8.  The Champions stayed with the little 169.62 cubic inch L Head six that had debuted at 164 cu. in. in 1939.   Other than a different bullet and grills and a more modern instrument housing, they were the same as a 1950 Champion.

So, one morning, I open my email and my brother has written asking for assistance diagnosing a cold starting problem with the Studebaker.  The symptoms; needing starting fluid to get it to fire, have to rev the engine for the first several seconds to keep it running and then rough idle for a while all pointed, in my mind, to a sticking automatic choke.  When I suggested that, he replied that it was the carburetor, not the choke.   Sigh.

For anyone with absolutely zero experience in the black arts that make carburetors work, the choke is one of several systems housed in the carburetor.  It is literally part of the carburetor.

So, how does one provide service that the owner doesn't want on a car that's 500 miles away?  Simple (I thought).  Send him a rebuilt carburetor that has a properly adjusted and working choke.

I found a number of the proper model carburetor on junk yards that sell on e-bay.  One was on a 1951 Champion so I bought it and ordered a rebuild kit.  When the carburetor arrived, it had a broken choke housing and the float bowl and all the passages were coated inside with a white mineral deposit.  Maybe it was corrosion.  It was tough - like enamel paint.  Not going to fix the choke with that and, not really being thrilled about having to clean out whatever that hard white deposit was, I bought one of the other Carter Model WE carburetors from e-bay.  I figured that as long as I swapped all the jets and things that made it fit one car or another, I'd be in good shape.  

When the second carburetor arrived, I noted several major differences between the two.  The second one has a much smaller bore and completely different venturi setup than the first.  I wasn't going to be able to just rebuild that one and swap in the right jets.  This job would require making the nasty one work again. It did, however, share two major castings with the first and one of those was the choke housing.  

The job was on.  I dismantled the one that I was going to salvage and ran it in the sonic cleaner. Didn't do much to clean it and didn't do anything on the white deposits.  The wife suggested trying vinegar so I filled the cleaner with a 50/50 mix of white vinegar and water. I let it soak for a week.  That did dissolve most of the mud and grease and it weakened the hard deposits enough that they could be scraped and wire brushed away.

Lots of brushing and picking with dental picks, wire brushes and gun cleaning brushes over the course of several weekends eventually produced a reasonably clean core upon which to assemble a properly working carburetor.

The rebuild kit was also from e-bay and it appeared to be well made.  It noted that all of its parts were compatible with ethanol gas too.  Brother runs ethanol free gas in the car but one never knows whether that will be available on a long trip. Options.

Some years ago, after I assembled my first AR 15 lower from a parts kit, a friend asked how difficult it was.  I told him that it was about like rebuilding a one-barrel carburetor.  Well, I guess I lied.  The AR was way easier.

Both deal with lots of mysterious little parts, clips, springs and check ballish things but there's several systems in a carburetor. They all interact and setting one system up affects the others. You have to assemble each system in the proper order and you have to make the various adjustments in the proper order. If you don't, all that time that you spent setting the choke unloader will have been wasted because you were supposed to set the fast idle cam first.


Fast Idle and Choke Unloader.  What could go wrong?

Besides having to go buy a couple of screw drivers and grind their tips to fit certain parts, the most troubling thing was the rebuild kit itself.  While well made, its instructions frequently referenced things that were not in the kit.  "Insert the metering rod gauge..."  Nope.  None in the kit.  "The clearance at the lower edge of the throttle valve should be as indicated in the table."   Table?  Nope.   It did have a thin cardboard gauge that worked for setting the choke unloader.  There was no table to tell me that the dimension was 3/16" but the gauge did have a 3/16" end and my shop manual had the table.  

The fast idle dimension for the throttle valve was supposed to be 0.45" according to the manual.  I wound up taking a micrometer and measuring all sorts of things around the house.  I didn't find anything that was 0.45" but I did find that one diameter on the metering rod from the donor carburetor was just under 0.45" and one small allen wrench that I have is just over. I set the clearance using the two as a go, no-go gauge.

Once all that was done, it was just a few minor clips and covers, oil a few linkages and the whole thing was back together.   

                                                            A gentleman always oils under the screw.

Not "Restored" to look like new but the choke moves freely.  Everything is set according to the book.  New gaskets.  New ethanol compatible needle and seat. New accelerator pump.  Just a neat old setup ready to give another seventy-three years of service.

Wednesday, December 27, 2023

Tuesday, December 26, 2023

Saturday, December 23, 2023

Wednesday, December 20, 2023

Tuesday, December 19, 2023

Monday, December 18, 2023