Author Topic: Holley Carb Leak?  (Read 1078 times)

Kelley W King

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Re: Holley Carb Leak?
« Reply #30 on: May 15, 2018, 11:10:58 AM »
Glad it is fixed. You may never know what the problem was. Next time post some pics so people will know what you actually have. The rear pump stuff really got people wondering.
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x66 714

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Re: Holley Carb Leak?
« Reply #31 on: May 15, 2018, 11:19:57 AM »
I'm glad to hear it's fixed Danny. I've been watching this post from the start because mine does something similar. Can anybody who knows the 4053 explain what ball Danny might be talking about in the secondary? Thank you, Joe
See America's First, Chevrolet

1968 Z/28 Corvette Bronze. Black Hounds Tooth. 02E Los Angeles born 3/13/1968 pnt OO. Purchased March 1976
1969 SS396 Yellow/Yellow 08E Norwood born 8/28/1969 pnt 76E. Purchased April 1981

cook_dw

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Re: Holley Carb Leak?
« Reply #32 on: May 15, 2018, 12:13:16 PM »
Secondary diaphragm check ball




Check ball is used to limit the amount of air the diaphragm sees and allows a more progressive opening of the secondaries.  If the check ball was left out it would not cause the issue that Danny was having.  Diaphragm still holds the secondaries in closed position through the use of the spring.  It requires velocity of air traveling across the venturi in order for the diaphragm & secondaries to work.  Simply revving the engine does not create the amount velocity for the secondaries to open unless to go WOT and even then it is very minimal.  Most than likely the pv was the issue in this case.
Darrell Cook


If you have a 68 L78 or Z28 Camaro please contact me so I can add your vehicle to my database.

Kelley W King

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Re: Holley Carb Leak?
« Reply #33 on: May 15, 2018, 12:46:30 PM »
I have replaced sec vac diaphrams and really did not notice the ball. Looks like it might keep a backfire from blowing the sec diaphragm also. I agree with DW that the check ball was most likely not the problem.
69 Z28 RS Scuncio Hi Performance
69 SS L78
67 SS Chevelle
64 Corvette
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77 Trans Am Special Edition

cook_dw

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Re: Holley Carb Leak?
« Reply #34 on: May 15, 2018, 12:54:18 PM »
Some carbs have it some don't.  Just depends on how its circuited..  But for this discussion the 4053 has the check ball and is needed to work correctly as per how it was engineered.



EDIT:

I have posted this before and is a good starting point in understanding how a Holley works..  There are more detailed articles out there but this one is good.


http://www.hotrod.com/articles/ccrp-0807-holley-carburetors-basics-guide/
Darrell Cook


If you have a 68 L78 or Z28 Camaro please contact me so I can add your vehicle to my database.

janobyte

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Re: Holley Carb Leak?
« Reply #35 on: May 15, 2018, 01:59:08 PM »
Quick question while we are on carbs: do the new holley 4053's come with blow out protection?

Had a lead on my oe carb but trail ended up cold. So picked up a new one last month. Emailed holley, waiting on reply. Vendor was not 100% sure.

68 Z/28  born with: 302, drive line, etc..

cook_dw

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Re: Holley Carb Leak?
« Reply #36 on: May 15, 2018, 02:16:56 PM »
I can't say for certain but you can pull the baseplate off and verify by looking for the valve.  I am pretty sure all carbs built now have them but I would still double check for piece of mind.  Waiting on Holley for a response may take a while FWIW.  They also offer a kit to install the valve into older carbs as well.


Image pulled from Google search.






Holley 125-500

https://www.jegs.com/i/Holley/510/125-500/10002/-1?CAWELAID=1710509952&CAGPSPN=pla&CAAGID=15769068431&CATCI=pla-194396695511&CATARGETID=230006180037474968&cadevice=c&gclid=EAIaIQobChMI9v3D5PKH2wIVxJyzCh3UeAD1EAQYASABEgJQiPD_BwE
Darrell Cook


If you have a 68 L78 or Z28 Camaro please contact me so I can add your vehicle to my database.

dannystarr

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Re: Holley Carb Leak?
« Reply #37 on: May 15, 2018, 03:44:56 PM »
Good to know on the check ball. THAT'S why the rebuilder said you really don't HAVE to have it. But glad it's back in if 4053's are supposed to have them. I have installed 6 of those 125-500 kits so far, in my cars and on some friends carbs. I DID make a mistake and installed/drilled one in the wrong place. Car would NOT run below high speed idle. So be careful when installing for correct location. I have bought 1 of the new 4053's and it did NOT come with that protection. I called Holley and they said they are not in there, and the tech didn't know why it wasn't in all new carbs. I can just about bet it won't be there. Just order the kit. MAKE SURE you set the bit depth  stop accurately. I am sure you will. It is a tricky measurement. Thanx again to all... Danny

janobyte

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Re: Holley Carb Leak?
« Reply #38 on: May 15, 2018, 04:30:41 PM »
Ok, thanks. On the shelf, so i will take a look later.
68 Z/28  born with: 302, drive line, etc..

Kelley W King

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Re: Holley Carb Leak?
« Reply #39 on: May 15, 2018, 05:52:38 PM »
I am running 3 Holleys now without the protection. I have had a blown out PV years ago but I think it takes a serious back fire.
69 Z28 RS Scuncio Hi Performance
69 SS L78
67 SS Chevelle
64 Corvette
66 GTO Tiger Gold
77 Trans Am Special Edition