I have decided that I dont care about originality anylonger. I hate the Rochester on the car as they are the worst possible idling carbs in the entire world. Is there a way to change it out or has anyone ever changed theirs. Id love to have a Carter as they are very easy to work with and they are just about the finest to work with.
I have a Rochester carb on my 76 Cpe de Ville and its been on there since 76 and it idles and runs like the day I got it. Any carb could go off so I would suggest you call "Hobbs Carburetor Shop" in Pelham, NH at 603-635-2415 and he's sure to take care of your carb if you have determined that the carb is your problem. He can send you a rebuilt one that will be like new and the cost is very fair. Just call him and see for yourself. EAM
Collector,
There is no reason that a properly rebuilt Q-jet will not idle correctly.
I have owned (and driven) dozens of Cadillacs over the last 30 years, and actually, I never had any carb problems with any of my cars.
Take the carb off, and send it out for a proper rebuild. If you want to keep the carb original, there are places that will re-build, and re-color the components to look factory fresh. You could also buy a used carb, keep your original one intact, and get the core rebuilt.
If you try to adapt something else, you have to change the fuel line, linkage, cruise control hookup, choke, etc......
You can get this to work.
Brian
Hello,
You may want to try these guys for either a rebuild of yours or advice on the best replacement - Carter or otherwise. They know their stuff and I'm sure they will be able to help you with your unit or with advice .
Daytona Parts Company
386-427-7108
www.daytonaparts.com
mail@daytonaparts.com
This company assembles nearly all the carburetor kits sold by other suppliers. They have the largest archive of original carburetor blueprints from the original manufacturers in the world. They make kits for virtually every automotive carb made from 1900 to 1980.
They also do top quality rebuilding of carburetors for those who don't wish to do it themselves. Check them out. You'll be impressed.
Ask for Ron Hewitt or Tim Hewitt.
I would run a vacuum gauge diagonstic test before you pull the carb.
A dry and a wet compression test too.
http://www.secondchancegarage.com/public/186.cfm
You did state you had a few pushrods that had problems.
Porter
You will be buying yourself a whole bunch more grief by even attempting to change the carb to something else.
You stated that there was a lot of gunk in the engine and that there were burred pushrods. Why would you think that all is OK to just put the engine back together? This is an indicator of deeper problems and I suggest that you do a more thorough diagnosis into this. If indeed this engine sat as long as it did, there may be stuck rings or valves that could have a bigger influence on idle quality that porting in the idle circuit in the carb may have.
Do a compression check, use a vacuum gauge like Porter suggests.
The carb will most likely need to be rebuilt for the reasons already suggesed.
This car has sat for a very long time and had little or no maintence done on it. That can be far more detrimental than having driven the car.
Mike
This came out of a 500. I never heard it run but it was in the guys daily driver pickup that he rolled over. He said it came out of a low mileage convert that had been sitting outside most of its life so the body was pretty far gone. He said the idle was a bit rough and he had a Holley on it. The oil pan and pickup tube had so much plastic in it I am surprised there was any oil pressure. The tips were all gone on the cam gear and I think there was one valve seal still more or less intact. Those heads are now in my car. I think all they did is a typical 'valve job' so things were not worn that bad because no hard parts had to be replaced.
(https://forums.cadillaclasalle.club/proxy.php?request=http%3A%2F%2Fi148.photobucket.com%2Falbums%2Fs35%2F73eldo%2FMisc%2Fvalve1.jpg&hash=57e9a93cbe83e8975e3c82a9945a7de29f204cb9)
Porter, That is the best article that I have ever seen on the use of the vacuum guage. Thanks, Herb Fearn #21704
You bet Herb.
Gotta run the proper troubleshooting tests.
My 66 429 pulls a steady 21 HG. on the vacuum gauge. Simple device and often overlooked by many.
Can't blame the carb here just yet.
Can use it to set your timing also if need be like up in the high altitude.
Maybe the mountain man John Washburn will jump in here - tuning expert.
If you don't have a strong steady needle on the gauge .....
Porter ;D
The vacuum gauge is a great diagnostic tool. Not only for the conditions described in that link, but for other things like checking ported vacuum signals for such devices as vacuum advances and EGR valves.
Also for searching out vacuum leaks in ancilary systems that don't work, or are weak and so forth.
The compression gauge can similarly find out specific problems if it is used correctly. No tool box should be without them.
Mike
If you want to trade, I may have a non rebuilt Carter which I don't care for.
If you want an easy reliable change you would likely want to go to a parts store and buy an Elderbrock, adapter plate, and pcs to change throttle linkage. I have a 56 with one mounted on it. And, I have to say, so far it is problem free. I may even buy one of those repro air cleaners off eBay and make it look stock.
Mr.Collector,
Surely you can find a brand new NOS Quadrajet to maintain the originality you demand. All of us have run quadrajets with a high level of success and if the wouldn't allow a decent idle you can be sure Cadillac would have corrected them. There is either a vacuum leak somewhere in the car or the carburetor has been poorly rebuilt or needs to be rebuilt correctly or there is something else wrong with your car.
More Quadrajets were replaced because of something else wrong with the engine. I have three "brand new but used briefly" carbs I bought in 72 for my eldo when I couldn't get it to run correctly. I don't remember what the real culprit was, but the carburetors, were not it.
Keep looking and you will find the Gremlin
Greg
Below is my response to another post because I think it may be relevant here.
Poor idle and other problems may be caused by today's gasoline and not by some malfunction of your car.
One of the problems that those of us who drive our cars regularly are facing now is the gasoline sold today isn't the same as it was 20,30,50 or 60 years ago. It's not even the same as it was last year.
Modern fuels are now formulated for modern cars with pressurized systems and fuel injection. They are more volatile than the fuels designed to run in our old vehicles. Cars which may already be prone to vapor lock are even more susceptible to it with today's fuels. Even if vapor lock doesn't occur, modern gasoline doesn't burn the same in our old carbureted engines.
Modern fuels can cause a host of problems that are sometimes impossible to diagnose when everything is in perfect order and meets factory specs. The gasoline, however does not meet factory specs for our cars and should be taken into consideration when trying to solve a problem that seemingly has no answer.
Ethanol is a big problem. I've been driving my 1956 CDV for 7 years as a daily driver. I've driven all over the Southeast on trips of over 2000 miles. I've never had a problem until recently. Many stations around here (Atlanta) now have signs saying gasoline may contain AT LEAST 10% Ethanol. That means it might contain more.
Ethanol is known to deteriorate, weaken and soften rubber. I have had to replace two fuel pumps this year because the diaphragm had been "stretched" and couldn't pump the volume required. One was a brand new pump, the other was a rebuilt unit.
On the '56, the pump arm travels only about 1/2". That doesn't allow for much error if the diaphragm is even slightly compromised.
I am now trying to find a brand that uses little or no ethanol. I may have to just bight the bullet and install an electric pump.
The point of all this is that the fuel you're using has to be considered as the source of any fuel related problem you may be experiencing. People who only drive their cars a few miles a year may not notice these problems but if you use your car for more than the occasional show, you will begin to see these problems.
I cannot seem to understand why you are having such a problem with the current gasoline with ethanol in it. I have five different cars and they "all" run perfectly with the ethanol. Never a problem.
Maybe you ought to examine your car a little more in depth to see why you are having a problem with this gas. I have a 76 Caddy. 86 Pontiac turbo, 89 Chevrolet Caprice, 90 Pontiac Bonneville and a 96 Buick Skylark and they all run very good with the current ethanol gasoline. How come you are having a problem? EAM
Your oldest car is at least 20 years newer than mine. I'm not having any problems with the way the car runs - only with its effect on certain rubber parts. This is a known problem with ethanol and some types of rubber components.
As for the gas itself, the federal government mandates so many different blends these days depending on the time of year, city or region, and even altitude, that the gasoline you buy will likely be quite different than the gasoline I buy.
Gasoline used to be the same from coast to coast. On a cross country trip today you could fill up your tank with as many as 12 different formulations depending on where you stop to buy it.
I'm not saying that the fuel is responsible for all fuel related trouble, just that it is something to consider when you have a problem.
In my case, all the evidence points to ethanol affecting the fuel pump. Other people may experience problems like vapor lock because of the higher volatility of modern gas.
It seems logical to take into consideration the fact that gasoline formulated for modern fuel injected systems is not the same as gasoline formulated for unpressurized, carbureted which were predominant when these older cars were built. Manufacturers of the time based their specifications for their vehicles on burning the gasoline that was available at the time - not the kind of gas that is available today. They had different octane ratings, different volatility ratings and different additives than today's gas.
So, all I'm saying is that all other things being equal, i.e. manufacturer's specs, that leaves fuel as the variable in the equation that could be the cause of someone's fuel related problem.
My old (non computer) cars only have a problem with fuel from one chain. They are a regional one that prides itself on 'green'. I suspect there is some other additive or perhaps a tenancy to get the blend a little on the high side that causes this. My newest cars seem to get slightly worse mileage when I use this brand of fuel also. Other than that one station vapor lock is the only problem I have with the blends we have had in our area for 10+ years now. Early on there were a lot of rubber problems but replacement parts all seem to tolerate it better. I have noticed that fuel lines get hard fairly quick.
Folks,
Just to add confusion to this thread. QuadraJets were made by both Rochester and Carter, so either is original.
John W.
I remember reading about the Carter Qjets. It seems it was a few years in the late 60's when GM (and a few others) went to the Qjets to meet emissions rochester was not able to keep up with demand.