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Carburetor FYI

Started by Hollywood, March 17, 2009, 05:37:31 PM

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Hollywood

The '65 Cadillac came with either a Rochester 4bl carb or a Carter 4bl carb.  What was the reasoning for this?  Was it an option one could choose, or something that either the earlier or later Cadillacs of that year would dictate?  Was one better than the other, and did this (option/situation) occur in other years as well?....Whew, just curious and any insight would be appreciated!....Thanks, H'wood
Eric D. Cook
1965 Coupe deVille

Chris Conklin

Not really fact, just my guess - Most businesses would maintain multiple suppliers to keep them all honest.
Chris Conklin

Hollywood

I think Chris' "guess" may have some validity...I had a similar thought, as this would be a general practice with any business.  Again, if their is some truth to that then the other questions still remain.  Did one have an option, did certain Cadillacs have one or the other, or was it purely random on which carb it received?....And yet, which manufacturer is better?   H'wood
Eric D. Cook
1965 Coupe deVille

35-709

Both carburetors were good but you will find those who favor one over the other.  I was always a Carter AFB fan, probably because that is what I was exposed to first and was more familiar with.  Someone else may be able to explain how some cars got one and some got the other, it was not an option thing.  More likely they did it in batches because there were differences in linkage, etc., maybe 100 Rochesters and then 100 Carters, etc.  Sorta like tires, Goodyears for awhile then U.S. Royals, then something else.
1935 Cadillac Sedan resto-mod "Big Red"
1973 Cadillac Caribou - Sold - but still in the family
1950 Jaguar Mark V Saloon resto-mod - Sold
1942 Cadillac 6269 - Sold
1968 Pontiac Bonneville Convertible - Sold
1950 Packard 2dr. Club Sedan
1935 Glenn Pray - Auburn Boattail Speedster, Gen. 2

John Washburn CLC 1067 Sadly deceased.

Boys,

My take, from talking to the old boys, is that it was an issue to keep the carburetor manufactures in line. After 1937, LaSalle came stock with Carter Carbs. Cadillac came with both Stromberg and Carter.

My belief is that both Carter and Rochester are good carburetors. One can discuss venturi, flow, and such but both perfromed well. My pet peeve is that Carter had the metering rods that went through the primary jets and after time and wear elongated the jet holes. I have rebuilt numberous Carter carburetors, that had been rebuilt,  early ones to AFB's, and very few had new primary jets.

So, if the rebuild kit does not have new primary jets, the carburtetor will not act as new. End of story.


End of Rant

John Washburn
John Washburn
CLC #1067
1937 LaSalle Coupe
1938 6519F Series Imperial Sedan
1949 62 Series 4 Door
1949 60 Special Fleetwood
1953 Coupe DeVille
1956 Coupe DeVille
1992 Eldorado Touring Coupe America Cup Series

kelly

I believe the idea of keeping carb. mfrs. "in line" may be a good one as well.  Both had to meet a performance spec., or they would not have been installed as new. Some '57 models came with Carter, some with Rochester. Mine happened to get a Roch. 4 Jet. I put a reman. on and it works quite well.  My attempt to rebuild was thwarted by excessive wear on the main butterfly shaft, causing excessive vacuum leak.
   In later model cars, the newer Qudrajet by Rochester gained a reputation as "QuadraJunk". I'm not sure if this rep. was deserved or not. Lots of people switched to Holley replacements rather than learn to deal with the Quadrajet, or hire a mech. who could.
Kelly Martin
Kelly Martin
1957 Fleetwood 75
2008 DTS

TJ Hopland

Was it perhaps a qudrajet made by Carter? There was a time around that period where I guess Rochester could not keep up with demand so Carter built the Rochester design.  I think it was around 67 when most of the emissions started, the Q-jet was the only carb that could fairly easily meet the requirements at first so it was very popular.  I have some Ford manuals from the time that show it for some models.
StPaul/Mpls, MN USA

73 Eldo convert w/FiTech EFI
80 Eldo Diesel
90 CDV
And other assorted stuff I keep buying for some reason

35-709

"I'm not sure if this rep. was deserved or not. Lots of people switched to Holley replacements rather than learn to deal with the Quadrajet, or hire a mech. who could."

Too bad.  The Quadrajet is an excellent carburetor and was used by GM, not just Cadillac, for many years for that reason.  Anyone who took the time to understand it, and its shortcomings (that all carbs. seem to have), had success with it and liked it.  For some reason it seemed to intimidate people because it was thought to be too complicated, a Holley would be a poor substitute overall.  A proper rebuild job on a Quadrajet is a far better solution than switching to a different carb and less expensive in both initial and operating costs.   
1935 Cadillac Sedan resto-mod "Big Red"
1973 Cadillac Caribou - Sold - but still in the family
1950 Jaguar Mark V Saloon resto-mod - Sold
1942 Cadillac 6269 - Sold
1968 Pontiac Bonneville Convertible - Sold
1950 Packard 2dr. Club Sedan
1935 Glenn Pray - Auburn Boattail Speedster, Gen. 2

joe12138

I've got two '65 Deville converts, 1 with the Rochester, 1 with the Carter. My experience is that the Rochester gives better fuel economy and maybe smoother acceleration, while the carter seems to have a lot more power and get up and go but sucks a lot more gas. But again, maybe it's just in the setup.

"Cadillac Kid" Greg Surfas 15364

Curious Joe,
What mileage do you get from each of them?
Greg
Cadillac Kid-Greg Surfas
Director Modified Chapter CLC
CLC #15364
66 Coupe deVille (now gone to the UK)
72 Eldo Cpe  (now cruising the sands in Quatar)
73 Coupe deVille
75 Coupe deElegance
76 Coupe deVille
79 Coupe de ville with "Paris" (pick up) option and 472 motor
514 inch motor now in '73-

Joe

I've gotten an honest 15-16 MPG with the rochester 4GC on highway driving. The Carter does about12-14 with the same type of trip. I don't check mileage too often, though. I didn't seek out 40 year old dreamboats with fuel economy as a goal!

"Cadillac Kid" Greg Surfas 15364

Joe,
Good to hear an honest man.  Most of us spend more on wax for our cars than gasoline, but mileage is just a kind of point of interest.  Typically a well running internal combustion engine (of 50's-80's era) will consume about .49 pounds of fuel per horsepower hour.  Stopping and starting 4800 pounds of Cadillac takes a lot of Torque, (hense the unbelievable 520 ft bls of the '429) abd torque relates to horsepower, and to get there that thakes fuel.
Mileage is extremely sensitive to driving habits.
You seem to have found the secret of the AFB.  Simplicity and CFM, and the CFM allows more mixture when you want it, and faster than seems to be the case with the Rochester.
Sorry for the rant, but I agree with you it would take a lot of gasoline savings to equal the no car payments and comfort.
Greg
Cadillac Kid-Greg Surfas
Director Modified Chapter CLC
CLC #15364
66 Coupe deVille (now gone to the UK)
72 Eldo Cpe  (now cruising the sands in Quatar)
73 Coupe deVille
75 Coupe deElegance
76 Coupe deVille
79 Coupe de ville with "Paris" (pick up) option and 472 motor
514 inch motor now in '73-

John Washburn CLC 1067 Sadly deceased.

Ok,

One last rant. With the AFB, the primary jets get out of round due to the metering rods. This = less gas mileage. Check the primary jets.

jw
John Washburn
CLC #1067
1937 LaSalle Coupe
1938 6519F Series Imperial Sedan
1949 62 Series 4 Door
1949 60 Special Fleetwood
1953 Coupe DeVille
1956 Coupe DeVille
1992 Eldorado Touring Coupe America Cup Series

Hollywood

Quote from: Joe on March 18, 2009, 02:08:15 PM
I've gotten an honest 15-16 MPG with the rochester 4GC on highway driving. The Carter does about12-14 with the same type of trip. I don't check mileage too often, though. I didn't seek out 40 year old dreamboats with fuel economy as a goal!
I may be mistaken, but I believe some of the "literature" for my '65 says that one could expect to get 10-12 MPG....Wow, if I would have expected to get that new no telling what kind of mileage I'd get now......Hmmm....I think I'll let that "sleeping dog lie".  I'm afraid to check!  :o H'wood
Eric D. Cook
1965 Coupe deVille