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Holley Carb Wizards?

Discussion in 'Shop Talk' started by Birken Vogt, Jun 17, 2016.

  1. Jim D

    Jim D Senior Member

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    What td25c said!

    If fuel runs or drops into the carb venturi (into the intake) when the fuel is pressurized but the engine isn't running, float level or needle valve leakage or internal leakage is the problem.

    If it seems like there is over-enrichment when the engine is idling or at throttle tip in, the ignition system could be the problem.

    Three psi fuel pressure to the carb, while it is on the bench, will tell you if there is a float level or needle valve or an internal leak problem. Plastic and rubber needle valve points die, and leak.
     
  2. RonG

    RonG Charter Member

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    I am a Mopar man too and have rebuilt many Thermoquads and have found that one gotcha to watch for is those composite floats that come in the rebuild kits need to be checked for floatation.I always put mine in a bowl and compare them for specific gravity and make sure that both floats are the same before I install them.Ron G
     
  3. lantraxco

    lantraxco Senior Member

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    And the o-rings in the bottom of the composite bowl yeah?
     
  4. Cam85

    Cam85 Senior Member

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    Don't do it to ur self mate Holleys are a nightmare I had a brand new 600 cfm vac secondary's square bore on the 308 in my boat and not me my mate Reece ore my old workshop foreman could get it to run right this was a fresh eng very mild new ign new internals ect paid big bucks for a guy from Brisbane to try and tune it ended up throwing the holly in the trash went for a quick fuel carb and never looked back about 45 minutes of fiddling and she has never played up since the extra $400 bucks on the carb is the best headache removal money I ever spent.

    If u decide to argue with the Holley some things to remember they like air lots of it if u change jets the power value may have to b monkeyed around with u will never get the throttle pump adjusted just right the later model bowl upgrades with auto shut off floats are a good thing 4wd bowls are a good thing big fuel lines are a good thing and high octane God new clean fuel is a good thing.

    But like I said don't do it to ur self go and talk to a local carb specialist they should b agel to sort out an upgrade for u no problems bolt on set mixtures and forget
     
  5. Cam85

    Cam85 Senior Member

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    A high quality vacuume gauge for tuning is a must also a new set of plugs is a good idea and have a look at leads dizzy cap rotor button ect if ur still running points buy a new electric ign dizzy bosh Dom good range and complete kits u will b surprised at how much better this setup is solves a lot of so called carb problems strait up if it was me I would do the pair and forget about it.

    That's only my opinion
     
  6. hetkind

    hetkind Senior Member

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    Sorry to hear about your boat motor issues...


    Holley makes a special marine carb, and boats don't need much in the way of accelerator pumps or vacuum secondaries.

    If the secondaries are mechanical, their only tuning is carb linkage AND main jets, and the main jets usually match the primary.

    Could you have gotten a second hand carb sold as new? I know many speed shops where the shops buddies have their pick of the stockroom and what doesn't work for them gets reboxed and resold to innocent walk in customers. I can't tell you the horror stories I have seen in the speed shops in the states.

    Howard

     
  7. fast_st

    fast_st Senior Member

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    Awww, I've had a few Holleys and they've been fantastic, a Holley isn't a Holley isn't' a Holley though, while they may all look alike and bolt up, you have to get the right center and match the airflow to the application, then the right power valve, squirters, idle and main settings, there is a process. Often for say if you were running a 308 at 6k rpm you'd need maybe a 500-550 cfm, so 600 is a little big, you'll loose a little snap out of the hole, Once you're sure your throttle shafts aren't leaking you start with the idle settings and go up from there. I've had a few that were screwed up all the way through with mish mash parts and a total headache. Holley has a huge table of parts for dialing in.
     
  8. Birken Vogt

    Birken Vogt Charter Member

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    OK so here is the final update on this saga.

    I was going to go with this guy http://www.thecarbshop.com/ but dragged my heels, and unfortunately his widow told me he was found dead under his work bench at about 82 years old and the fire department had to pry the door open to get to him since he locked it good in his inner city shop I guess.

    His friend Diego was supposed to be taking over the business but I got no return call from him.

    The only other place that looked like a good fit for me was this: http://www.carburetorusa.com/ so I contacted him and sent the carb off in March or April. Apparently he has a lot of work, months went by, I called, he told me the place in the queue, it moved up very slowly and when he did get to it it was a long time to rebuild. All kinds of things wrong with it, the "new" floats were bad, governor problems, and parts extremely rare.

    So in September or October I finally got it and put it on the shelf where it sat till today since I had no time or the weather was too rainy to work, or both.

    Put it on, fired it up, truck purrs like a kitten (for an old HD gas pot that is)

    I was impressed with his skill and work quality and expertise even if it did take a long time.

    Now I am getting no oil pressure reading but I think it is an electric problem, single sender terminal measured no voltage stopped or running and I can hear oil trickling back to the pan when I shut down so I am pretty sure it has pressure, no reason for it not to. On to that another free day.
     
  9. td25c

    td25c Senior Member

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    Glad to hear you got it fixed Birken !
     
  10. Willie B

    Willie B Senior Member

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    Mine is a 1976 Chevy (see avatar) 427 truck engine. After a few rounds with the Holley, I gave in. A longtime acquaintance worked in a parts store. He's into Chevy big blocks. He convinced me to switch to an Edlebrock. I have never regretted it. I want to say it is a 550CFM that can be converted up to 650 CFM.
     
  11. Birken Vogt

    Birken Vogt Charter Member

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    I had considered switching, but with all my misadventures switching stuff like this around, I didn't want to get into a secondary project. This thing runs an Ottowa backhoe (pictures of that soon) and I don't know how the distributor mount vacuum governor interacts with the hydraulic pump, etc. I just want it to work the way it was intended to work. Also in the previous post I forgot to mention cost. North of $400 if I recall correctly. But I would do it again if I had some kind of special truck that needed it. If I could stand the wait.
     
  12. Willie B

    Willie B Senior Member

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    There is a guy in Castleton VT usually does them next day.
    I know he receives them UPS, and FedEx. from all over the country.

    Willie
     
  13. Birken Vogt

    Birken Vogt Charter Member

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    I also wanted to thank you for this tidbit. Even though it really was the carburetor in this case.

    This little tidbit has really helped crystallize my thinking. I work on a lot of spark ignition engines with problems "nobody else has been able to fix" and looking back on my experiences, the above quote always seems to be the cause of failure.

    Just last week I had a small single cylinder engine with plenty of fuel, spark and compression known to run good recently that would weakly fire or pop out the intake. Replacing the coil was all it took. I guess it was still sparking, just at the wrong time.

    The trouble with ignition problems is they are so hard to prove without swapping one-of-a-kind parts that if you get wrong, you eat.
     
  14. Ratmotorhead

    Ratmotorhead Well-Known Member

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    Float level is high Loosen the flat screw on top of bowl and turn the nut to lower the float there is a window on side of bowl gas should just trickle out when idling. If it keeps coming out side window hole the seat is bad at float
     
  15. smoke

    smoke Member

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    im 100 % a holley man for almost 55 years...best carb made, easy to repair easy to adjust...if its a 4 barrel remember this the frt butter flys cannot be open at idle more than the small air ports located in the frt bores...if they are past those two slots it will render your air mixture screws useless
     
  16. f311fr1

    f311fr1 Senior Member

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    Dean Nickerson in Bristol PA for carb work.
     
  17. Willie B

    Willie B Senior Member

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    I had a book on Holley carbs, I loaned it when I bought the Edelbrock, I think I could get it back. There was a boatload of theory in it.
     
  18. hetkind

    hetkind Senior Member

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    My book on Holley carbs is on the shop shelf. I am running a two barrel on both 62 Town Wagon and 68 Utiline...the 7448 350 CFM. I like the smaller venturies since they improve bottom end torque. What info do you need?
     
  19. DMiller

    DMiller Senior Member

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    One of the most often ignored aspects of these is being tanks too much. The anodizing erodes over time to where becomes non-existent. We found out in the early years of throttle body when the coatings wore off the bodies the Idle Air Control could not make up for thru the aluminum vacuum leaks, a problem experienced on carbs but never identified as could somewhat adjust those out, kind of. Too old, all the anodized coatings gone and you may never get a carb to run reasonable. Power valves were a real PITA as the first back sneeze an engine makes usually pops the diaphragm, then you have to pull the jet block to replace it, floats can be fine as to set and the power valve leak that cannot be adjusted for while runs rich as hell.