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-   -   Which carburetor to use, Rochester or Carter? (https://67-72chevytrucks.com/vboard/showthread.php?t=815774)

AZ59apacheguy 12-16-2020 12:58 PM

Which carburetor to use, Rochester or Carter?
 
Hello all. Currently I have a 283 with a stock manifold and Holley carb. When tuned correctly it runs good, but I am tired of constantly having to mess with the primary/secondary float adjustments on this thing; seems as though I am doing it monthly. Having to use an adapter to mate the carb to my stock manifold, I just think it best to go back to a period correct carb. I know back in the day they used both Rochester 4GC's and Carter WCFB's. Searching the inter-web yields more Rochester's available than Carter's. Is one better than the other? Thanks

geezer#99 12-16-2020 01:38 PM

Re: Which carburetor to use, Rochester or Carter?
 
Shouldn’t need constant adjustments.
Might be a fuel pressure problem or level setting.

Changing to either new carb might not help. I think either one needs a max of 5psi.

Have you tried setting fuel level about 1/8 inch lower?
Where in the sw are you located?

AZ59apacheguy 12-16-2020 02:07 PM

Re: Which carburetor to use, Rochester or Carter?
 
1 Attachment(s)
Quote:

Originally Posted by geezer#99 (Post 8850741)
Shouldn’t need constant adjustments.
Might be a fuel pressure problem or level setting.

Changing to either new carb might not help. I think either one needs a max of 5psi.

Have you tried setting fuel level about 1/8 inch lower?
Where in the sw are you located?

Hi. I live in AZ. Fuel pressure is plenty good, not sure what " Level Setting " is, can you explain? Both Primary and Secondary floats are set with a little fuel leaking out like manufacture recommends. When setting the floats lower than level with the site plug, truck would stall with moderate braking. A little more history of my current setup...... A hot rod buddy of mine jetted down and placed this 650 Holley on my 283. He put a sniffer at the tail pipe and all the numbers fell within smog specs. I am not a skinny pedal stomper and am not looking for super high performance, I am really just looking to go back to as stock a set up as I can. Thanks
Attachment 2068076

geezer#99 12-16-2020 04:21 PM

Re: Which carburetor to use, Rochester or Carter?
 
Plenty good pressure could be too much.
Level setting is float level. Normally I set it lower than the factory says. About 1/8 inch lower.
You have center hung floats. They do flood when stopping hard. Side hung are better.
Can’t see your adaptor for the carb to intake.

Looks like you have a fuel pressure gauge.
What’s the pressure at?

AZ59apacheguy 12-16-2020 04:36 PM

Re: Which carburetor to use, Rochester or Carter?
 
Quote:

Originally Posted by geezer#99 (Post 8850838)
Plenty good pressure could be too much.
Level setting is float level. Normally I set it lower than the factory says. About 1/8 inch lower.
You have center hung floats. They do flood when stopping hard. Side hung are better.
Can’t see your adaptor for the carb to intake.

Looks like you have a fuel pressure gauge.
What’s the pressure at?

After I adjusted them level the last time, it will not stall when I brake, so that fixed that issue. It's around 9psi after warm up, higher when it first starts.

geezer#99 12-16-2020 04:48 PM

Re: Which carburetor to use, Rochester or Carter?
 
Put a fuel regulator on it.
No carb needs more than 5psi.

AZ59apacheguy 12-16-2020 05:55 PM

Re: Which carburetor to use, Rochester or Carter?
 
Quote:

Originally Posted by geezer#99 (Post 8850852)
Put a fuel regulator on it.
No carb needs more than 5psi.

Thanks for the info. I am already sourcing one as we speak, I also think I have one somewhere at home. I guess my question is, what did they do back in the old days? It is a stock mechanical fuel pump, the same used back in the day.....

Tom 12-16-2020 06:07 PM

Re: Which carburetor to use, Rochester or Carter?
 
I agree something is off. I've had to reset float level exactly zero times in my life driving here in Phoenix.

Dead Parrot 12-16-2020 06:43 PM

Re: Which carburetor to use, Rochester or Carter?
 
Quote:

Originally Posted by AZ59apacheguy (Post 8850877)
....I guess my question is, what did they do back in the old days? It is a stock mechanical fuel pump, the same used back in the day.....

They just ran the pump straight into the carb. Pretty sure QA was better then. Seems a fair percentage of the newer pumps put out too much pressure.

cadillac_al 12-17-2020 07:40 AM

Re: Which carburetor to use, Rochester or Carter?
 
I don't know where you guys get those high pressure fuel pumps. Every one I buy only puts out 5 psi. I would get a Qjet off a 305 and be done with it. The Holly does look cooler though.

AZ59apacheguy 12-17-2020 10:27 AM

Re: Which carburetor to use, Rochester or Carter?
 
Hi all, thanks for the responses. So after work yesterday, I did a little fiddling on the carb. First thing is I found another pressure gauge, removed the current and installed the new one. Fired her up and fuel pressure was just under 6psi, so it seems my pressure is good and the last gauge was bad. I then let her warm up and pulled the sight plugs, the front float was level and once again the back float was high! Adjusted that and the engine runs better. Why does the float keep going out of adjustment?

AZ59apacheguy 12-17-2020 10:30 AM

Re: Which carburetor to use, Rochester or Carter?
 
Regardless, I still want to go back to a period correct carburetor for my 1959 1/2 ton. So which one is better, Rochester 4GC or Carter WCFB, does one have an advantage over the other? Thanks

vince1 12-17-2020 11:20 AM

Re: Which carburetor to use, Rochester or Carter?
 
I don't think you're going to find too many old timers here that would have had experience with both carbs from back in the fifties and sixties to give an accurate comparison.

Personal bias for me would be to go for the Carter. I have a 2 barrel WCD that I like a lot.

Those old WCFB's and 4GC's sure are expensive on EBay.

Dead Parrot 12-17-2020 11:56 AM

Re: Which carburetor to use, Rochester or Carter?
 
Might look at this: https://www.edelbrock.com/performer-...-egr-1404.html

The 14xx family is based on the Carter AFB which is period correct for your vehicle. It would have the advantage of lots of parts support.

geezer#99 12-17-2020 12:39 PM

Re: Which carburetor to use, Rochester or Carter?
 
Choice of carb depends on what year intake you have.
You’ll need to pull the carb off and measure the carb mounting bolt pattern.
There were some pattern changes around 1960.
And the throttle bore spacing changed as well.

AZ59apacheguy 12-19-2020 11:14 AM

Re: Which carburetor to use, Rochester or Carter?
 
1 Attachment(s)
Did some more fiddling and got some advice from my hotrod buddy yesterday. He said it sounds like the 0-ring has has gone bad and fuel is probably getting passed the needle valve. Sure enough, pulled the needle valve and the o-ring crumbled in my hand. Installed two new needle valve and will adjust sometime this weekend.
Attachment 2068497

AZ59apacheguy 12-24-2020 02:18 PM

Re: Which carburetor to use, Rochester or Carter?
 
Quote:

Originally Posted by cadillac_al (Post 8851059)
I don't know where you guys get those high pressure fuel pumps. Every one I buy only puts out 5 psi. I would get a Qjet off a 305 and be done with it. The Holly does look cooler though.

What brand/model fuel pump are you using? I just bought a Carter M4172 and it is rated at 5.5 to 6.5 psi max pressure

mattfranklin 01-20-2021 06:47 PM

Re: Which carburetor to use, Rochester or Carter?
 
Not to nitpick, but normally you just set the float level and leave it.
Then you adjust the idle mixture screws to keep it from dying and to make it idle smoothly. I skimmed through the post kind of quickly, so I may have missed the part where you said you were adjusting your idle mixture screws.

But also, I appreciate the part where you said you wanted to get it as stock as possible. Stock is stock and easier to adjust and specify parts for. Nothing to remember, other than the word "stock." ;-)


Quote:

Originally Posted by AZ59apacheguy (Post 8850845)
After I adjusted them level the last time, it will not stall when I brake, so that fixed that issue. It's around 9psi after warm up, higher when it first starts.


AussieinNC 01-21-2021 12:19 PM

Re: Which carburetor to use, Rochester or Carter?
 
Quote:

Originally Posted by AZ59apacheguy (Post 8851837)
Did some more fiddling and got some advice from my hotrod buddy yesterday. He said it sounds like the 0-ring has has gone bad and fuel is probably getting passed the needle valve. Sure enough, pulled the needle valve and the o-ring crumbled in my hand. Installed two new needle valve and will adjust sometime this weekend.
Attachment 2068497

Yeppers...pump gas with ethanol will chew up older O rings pretty quick....



:chevy::chevy::chevy:

68Gold/white 01-21-2021 03:08 PM

Re: Which carburetor to use, Rochester or Carter?
 
Quote:

Originally Posted by AZ59apacheguy (Post 8851837)
Did some more fiddling and got some advice from my hotrod buddy yesterday. He said it sounds like the 0-ring has has gone bad and fuel is probably getting passed the needle valve. Sure enough, pulled the needle valve and the o-ring crumbled in my hand. Installed two new needle valve and will adjust sometime this weekend.
Attachment 2068497

I had to perform this on a Holley recently, seemed to have seepage on rear float bowel, it fixed the problem!!!

CCCC 01-23-2021 09:39 PM

Re: Which carburetor to use, Rochester or Carter?
 
I have been running both types of carbs, for quite a while. The Qjet seems more complex and not as easy to rebuild, but when it is properly rebuilt and working right, it seems somewhat more flexible - little bit better mileage and good power performance. But, the Carter is easier for me to deal with and I like the set-it-and-forget-it aspect on most of these engines.

For these carbs, those comments about problems with fuel pressure over 5 psi are on the mark. I have learned to look at the pump specs before buying.


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