Rochester 4 bbl carb squeal - The 1947 - Present Chevrolet & GMC Truck Message Board Network

ChevykidHB · 11-06-2013, 12:56 AM

hey guys got a 350 with the Rochester 4 barrel. and its got what i though was a belt squeal but turns out its the carb? time for a rebuild? or is it just a vacuum line? thanks!

Twisted78SS · 11-06-2013, 01:04 AM

Ya know, I think I have one of those too,

Thought maybe it was just me.. Mine is a brand new old stock Edelbrock quadrajet. Not sure what to do about it, can't find any leakes etc..

ChevykidHB · 11-06-2013, 01:10 AM

i have a feeling its a vacum leak but i dont know much about carbs at all. im learning as i go. my secondaries also seem to not open which makes me think it might be a vacum leak.

ChevykidHB · 11-09-2013, 10:45 PM

scratch all that. was the belt. swap yours out if you haven't already

swamp rat · 11-10-2013, 01:09 AM

Quote:

Originally Posted by ChevykidHB

scratch all that. was the belt. swap yours out if you haven't already

That's funny as hell, i had a belt squeal that was driving me nuts, i was blaming the alternator bracket alignment, alternator pulley, and even the water pump pulley alignment even tho i had seen worse alignment not squeal at all, tried 3 different belts too, turned out it was an unplugged vacuum line on the back of the carb.

ChevykidHB · 11-10-2013, 01:30 AM

haha right on it was really driving me crazy for a few weeks until i finally got it

Twisted78SS · 11-10-2013, 01:37 AM

Well,

Can't blame the belts on mine, I ran it without any belts at all as a means to eliminate them.. Still have a sqeel / squeak.. Vacuum gauge doesn't indicate a leak that I can pinpoint..

Not sure what to do next. Only happens a 1/2 3/4 throttle

**bigmac73** · 11-10-2013, 06:59 AM

sounds like it is just air flow going into the air horn on the top of carb, i had a 72 with a 307 before and every time you downshifted and stomped it , it would made a squeak or whine sucking air in,does it happen with the air cleaner off??

swamp rat · 11-10-2013, 12:54 PM

Woops, i stand corrected, it was the port on the manifold for the transmission not a port on the carb, i had used the port on the carb then forgot to plug the fitting on the manifold.. so i plugged the carb port and went back to the manifold port and problem solved.

ChevykidHB · 11-11-2013, 06:51 PM

damit! spoke to soon. i tested it out again today and it still making that squeal with and with out the air cleaner. what did you do to fix the carb on the 307?

11-06-2013, 12:56 AM	#1
ChevykidHB Registered User Join Date: Oct 2013 Location: Huntington Beach, California Posts: 18	Rochester 4 bbl carb squeal hey guys got a 350 with the Rochester 4 barrel. and its got what i though was a belt squeal but turns out its the carb? time for a rebuild? or is it just a vacuum line? thanks! __________________ 1970 c20 cst 350/400 14bolt rear

11-06-2013, 01:04 AM	#2
Twisted78SS Wide n'Low Join Date: Jan 2007 Location: La Center, WA Posts: 1,511	Re: Rochester 4 bbl carb squeal Ya know, I think I have one of those too, Thought maybe it was just me.. Mine is a brand new old stock Edelbrock quadrajet. Not sure what to do about it, can't find any leakes etc.. __________________ Trippin Hazard.. 67 swb, Gold Member.. 68 Suburban Air Force Retired

11-06-2013, 01:10 AM	#3
ChevykidHB Registered User Join Date: Oct 2013 Location: Huntington Beach, California Posts: 18	Re: Rochester 4 bbl carb squeal i have a feeling its a vacum leak but i dont know much about carbs at all. im learning as i go. my secondaries also seem to not open which makes me think it might be a vacum leak. __________________ 1970 c20 cst 350/400 14bolt rear

11-09-2013, 10:45 PM	#4
ChevykidHB Registered User Join Date: Oct 2013 Location: Huntington Beach, California Posts: 18	Re: Rochester 4 bbl carb squeal scratch all that. was the belt. swap yours out if you haven't already __________________ 1970 c20 cst 350/400 14bolt rear

11-10-2013, 01:30 AM	#6
ChevykidHB Registered User Join Date: Oct 2013 Location: Huntington Beach, California Posts: 18	Re: Rochester 4 bbl carb squeal haha right on it was really driving me crazy for a few weeks until i finally got it __________________ 1970 c20 cst 350/400 14bolt rear

11-10-2013, 01:37 AM	#7
Twisted78SS Wide n'Low Join Date: Jan 2007 Location: La Center, WA Posts: 1,511	Re: Rochester 4 bbl carb squeal Well, Can't blame the belts on mine, I ran it without any belts at all as a means to eliminate them.. Still have a sqeel / squeak.. Vacuum gauge doesn't indicate a leak that I can pinpoint.. Not sure what to do next. Only happens a 1/2 3/4 throttle __________________ Trippin Hazard.. 67 swb, Gold Member.. 68 Suburban Air Force Retired

11-10-2013, 06:59 AM	#8
bigmac73 Senior Member Join Date: Mar 2012 Location: Chesapeake, Va Posts: 1,275	Re: Rochester 4 bbl carb squeal sounds like it is just air flow going into the air horn on the top of carb, i had a 72 with a 307 before and every time you downshifted and stomped it , it would made a squeak or whine sucking air in,does it happen with the air cleaner off?? __________________ Mike 72 C-10 Cheyenne off frame resto and Upgraded to 4 wheel disk, Tilt, Dakota Digital Dash / Rear slider. 421 SBC / TH350 3000RPM Stall Progression Ignition /Holley 750 DP/3:73 gear Eaton Limited Slip unit / 2 1/2 exhaust glasspacks

11-10-2013, 12:54 PM	#9
swamp rat Registered User Join Date: Oct 2007 Location: Spanaway Posts: 8,451	Re: Rochester 4 bbl carb squeal Woops, i stand corrected, it was the port on the manifold for the transmission not a port on the carb, i had used the port on the carb then forgot to plug the fitting on the manifold.. so i plugged the carb port and went back to the manifold port and problem solved. __________________ Mike. Swamp Rat build thread : http://67-72chevytrucks.com/vboard/s...d.php?t=595019 72 3/4T 4X4 4" BDS Lift 33" BFG's

11-11-2013, 06:51 PM	#10
ChevykidHB Registered User Join Date: Oct 2013 Location: Huntington Beach, California Posts: 18	Re: Rochester 4 bbl carb squeal damit! spoke to soon. i tested it out again today and it still making that squeal with and with out the air cleaner. what did you do to fix the carb on the 307? __________________ 1970 c20 cst 350/400 14bolt rear



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