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The "hated" Holley carb! *UPDATE* Its fixed!

Discussion in '1973-1991 K5 Blazer | Truck | Suburban' started by Pure Insanity, Oct 14, 2001.

  1. Pure Insanity

    Pure Insanity 1/2 ton status

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    The \"hated\" Holley carb! *UPDATE* Its fixed!

    Most here have beat the Holley to death, because of the hill climb problems, and I understand that. I have defended them to the end having never had a problem on hills w/ mine.

    I pulled it apart today to reseal the front metering block and bowl, for a leak after it sat up for a long time. I found the reason I have never had a problem, mine has had an "anti slosh kit" installed. Basicly all it is, is a plastic rectangular vent, that extends to the front of the front bowl. Its called a "whistle vent" by Holley.

    Ok now I have a question, it is a 4150 carb w/ primary and secondary metering blocks, (not a sec. metering plate) dual feed w/ mechanical secondaries. It will idle fine and wrap up great, but it seems to give the motor a shudder just off idle that feels like a motor vibration. but if you go from idle to WOT, it skips over the vibe and tachs out. Its not a hesitation like stomp it and it falls on its face then takes off, its more like rolling into the throttle you will feel the shudder for a sec. then hang on. Also, the idle mixture adj. on the left side of the carb doesnt seem to do anything. The right side will do the normal bog down when you play w/ it, but the left side does nothing. Screw it in or out and nothing changes. I put in a new power valve while I had it apart, will this cause the shudder? I dont know much about the power valves and how they work. The one that was in it I think got wasted in a carb backfire, so I put in another. I may put it back in and see what happens.

    Everything is great except for the shudder. It runs excellent otherwise. and when I was playing w/ it I would stick my head under the Blazer to see if it smelled rich, and it did not, so I dont think its flooding and then sucking it up.

    Anyone have any advice???

    If ya can't stop.......Smile as you go under! &lt;img src="http://coloradok5.com/forums/images/icons/smile.gif"&gt;<P ID="edit"><FONT class="small">Edited by pureinsanity on 10/15/01 07:15 PM.</FONT></P>
     
  2. Thunder

    Thunder 3/4 ton status

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    Re: The \"hated\" Holley carb!

    You may need to put a stiffer spring in the vacume pod that controlls the vacume secondaries. Holley makes a kit that contains a bunch of springs to fine tune the opening of the secondaries. If they open too soon it will make the engine bog a little on aceleration
    Tuning Holleys is just one of the little joys of owning one.
    Your idle mixture scrwes should work on both sides. The valve body may need to be cleaned to get the left side working right.

    <a target="_blank" href=http://coloradok5.com/gallery/Thunders-Blaze>http://coloradok5.com/gallery/Thunders-Blaze</a>
    <font color=blue>NEVADA: Where the pavement ends, and the West begins.</font color=blue>
     
  3. Sparky87k5

    Sparky87k5 1/2 ton status

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    Re: The

    Thunder,
    "it is a 4150 carb w/ primary and secondary metering blocks, (not a sec. metering plate) dual feed w/ mechanical secondaries" This is not your street vacuum secondary type carb.
    Pureinsanity, what version carb do you have. On the front of the airhorn is a "list" # and model #. What are they?

    A good firm grip is my idea of gun control!
     
  4. Pure Insanity

    Pure Insanity 1/2 ton status

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    Re: The

    Its a mech. sec. carb. I dont like the vac. sec. I want to KNOW what is going on not come to an incline and have the carb decide what to do for me. LOL!

    After thinking about the shudder till almost 3 AM last nite, [​IMG] I figured that there must be some gasket material in the idle circuit on the left side. That would prob explain the shudder. Its hitting fine on the right side but the left side is going lean and is weak, But once it gets off the idle circuit and gets into where the carb is making power, its now flowing fine thru the jets, and flowing evenly.

    How is tuning one of the little joys of owning a Holley?? You have to tune a Qjet or Edelbrock. And when it comes to fine tuning a carb, the Holley just cant be beat. No metering rods, or little flapper over the secondaries, to tell the carb how much air is flowing thru.( I am drawing a blank on its name because I am not feeling too swift this morn. ) Play w/ that adjustment some time and see how much fun there is to be had getting it right again. Other than the fact that they make a mess cleaning up the gasket material when you break it down and you cant reuse the gaskets, they are incredibly simple to work on, and fine tune.

    As far as constant adjustments, I also disagree. I bolted this same carb on my last motor, tuned it once and forgot it. I retuned it after I let the rig sit for 5 years, and had to rebuild it. After I rebuilt it and retuned it, I drove the crap out of it for over 3 yrs, and never touched it.

    Most peoples perception of the Holley comes from people that play w/ them they go lean or the timing is not set correct and back fire thru the carb , blowing the power valve. If most people would actually TRY to work w/ one and read about and listen to people that do know them, they would be pleased. Most prob. I have seen come from blowing the power valve, after a carb back fire and it pops the power valve. After that happens, it will run rich no matter what you do, at all eng. speeds. The new Holleys have blowout protection on them.

    I will admit a stock Qjet will pract. run upside down, but beyond that, I see no other advantage. Put in the whistle vent and get similar results on hills w/ the Holley.

    I am not trying to put anyone down or anything, its just that my last rig had this same Holley and I great success w/ it. Idled fine and ran good all the way up to where I would shift at 7000 RPM (when ness.) and never once ran out of power due to going lean on the top.

    Its all in what you prefer, if you really want to run one, you will do the ness. reading and such to find out what has happened. 90% of the time its the power valve, which the others dont use so most people dont think of them.

    I just dont understand how such a simple carb can be considered so hard to live w/.

    If ya can't stop.......Smile as you go under! [​IMG]
     
  5. Pure Insanity

    Pure Insanity 1/2 ton status

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    Re: The

    The carb has been modified and the choke horn was milled off. So the numbers went w/ it. [​IMG] I would really like to know exactly what size it is, but there is no other way to know except those #s, that I know of.I am pretty sure it is between 750-850 CFM. It came off of a 350, so it should work fine on mine. I ran it for yrs on my Jeep 401 and it was perfect. The 350 I have in the Blazer is more motor than the 401 was so I figured it would be fine also and is, except this new found shudder.

    If ya can't stop.......Smile as you go under! [​IMG]
     
  6. K5RON

    K5RON 1/2 ton status

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    Re: The

    Tried the "Holley" thing with not much luck! Yes the "whistle" does help on the bowl vent but doesnt do much for the venturies and it won't fit with side hung floats! A slosh screen is made for the side hangers but it doesn't work well either.

    I went with 2BBL Pro-jection and love it! Extra crisp throttle response, easy set-up, take-off immediately upon starting and the big one.....no off camber flooding!

    Try your Holley over some medium size "whoops" , if it doesn't stall, you may have something there.

    Good luck, 'cause I had none.


    Ron


    '84 K5......Tree Fitty, SM465/Np205, D44/14BFF, Pro-jection! .....and of coarse no other color than Odie!
     
  7. 502Burban

    502Burban 1/2 ton status

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    Re: The

    It's been a while since I played with Holleys (all vehicles FI, now), but a couple things you might try. I agree that you may have some gasket debris clogging one side of the idle circuit. Obvious fix is to tear-down, clean and blow-out with compressed air.

    As for your power valve, just make sure that you used the same one that you had before, if it was working correctly. If your engine configuration has changed, you can size the power valve correctly by going with a size that is 1.5"-2" less than your cruise vacuum reading. If your engine cruises at 8" of vacuum, run a 6.5" power valve.

    The whistle you found will help with running on an incline. You can also get jet extenders, and (the best improvement, IMO) a spring-loaded needle and seat. I ran this setup on a 600cfm double-pumper mounted to a V8 CJ5 with good results. It takes some fiddling to get the seat height adjusted so that it won't flood on a hillside, but once you get it right you won't have to mess with it anymore.

    Hope this helps,

    Robb
    '73 GMC Suburban - 502DFI
    <a target="_blank" href=http://community.webshots.com/user/robbrj>community.webshots.com/user/robbrj</a>
     
  8. Pure Insanity

    Pure Insanity 1/2 ton status

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    Re: The

    If the whistle stops the fuel from sloshing out of the bowl it stops it from making it to the veturies, and flooding.

    I have been down some bumpy roads and such but never over whoops. I am not into the high speed bounce thing. I like keeping all 4 on the ground as much as possible. [​IMG]

    Inj. is nice, I do have to admit that, but I dont like computers of any kind on my rig. I can have a fire in the eng. compartment, rig up some wires and get it out of the woods. W/ a computer you will be towed out. There is just no way to rig up an injected truck, unless you carry a spare harness.

    I do like the inj. But I prefer simplicity, when I am 20 miles from nothing in the woods.

    If ya can't stop.......Smile as you go under! [​IMG]
     
  9. K5RON

    K5RON 1/2 ton status

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    Re: The

    Yeh, I agree with the "user friendliness" of the carb. And the ability to "limp" home, but I think your more likely to get struck by lightening than have an underdash fire.

    Take your carb off and block off the bowl vents, then (not vigorously) shake the carb. you'll see!.........fuel will flow from the venturies. There is nothing in the circuit holding it back, otherwise the engine would get no fuel!


    Although harder to tune and parts availablilty is not so good, I'd run a Q-jet if there was a choice! (Q-jets will stall on "Whoops" also)

    I tried everything to make the Holly run off-camber i.e. extending the bowl vents, slosh screens, fuel pressure regulators, float levels, spring loaded needle and seat, larger damper spring on the float, different float composition. The thing that I found that worked the best was a shut-off button on the shifter that killed the electric fuel pump 'til I got through the tough stuff! I even had one of the stupid things that set fuel pressure according to engine vacuum. JUNK!

    I'm not saying Holley carbs SUCK just that I, in my experience, had no luck with Holley's in off camber situations.



    Ron


    '84 K5......Tree Fitty, SM465/Np205, D44/14BFF, Pro-jection! .....and of coarse no other color than Odie!
     
  10. Sparky87k5

    Sparky87k5 1/2 ton status

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    Re: The \"hated\" Holley carb!

    Off idle "shudder" as you describe it can be caused by the either the accel pump cam being in wrong hole or wrong cam used for your application. This cam is located on primary throttle rod lever. Holley makes various cams for many applications. The cam dictates the start, length and volume of accel pump discharge. Other item might be your "shooter" size. Acell pump discarge nozzels can be varied to increase quantity of fuel discharged. Most Holleys use something in the range of .028 - .032 nozzels. Hope this helps.

    A good firm grip is my idea of gun control!
     
  11. shupach

    shupach 1/2 ton status

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    Re: The \"hated\" Holley carb!

    ok i happen to have a 750 cfm holley double pumper, i realized that carb is too big, for how much can i sell it and where can i get a qjet(junkyard). and if i get a qjet wat must i look for? im not a carb genious, i just want something that works.

    phill
     
  12. K5RON

    K5RON 1/2 ton status

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    Re: The \"hated\" Holley carb!

    Well, if your running a Holley and want to go Q-jet, you'll need an adapter or a different manifold! Unless you have one of the old Holley spreadbores!


    Ron


    '84 K5......Tree Fitty, SM465/Np205, D44/14BFF, Pro-jection! .....and of coarse no other color than Odie!
     
  13. Pure Insanity

    Pure Insanity 1/2 ton status

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    Re: The

    Ron, all carbs have to bleed in fuel to the venturies. Maybe the Holley is more suscptible, I dont know. An under hood fire will also wipe out the harness. That is as simple as getting the tranny overheated w/ a plugged vent and having ATF puke out the dip stick tube and catch fire on the headers. like I said before I like Inj. I just prefer simplicity, thats all. I understand your not saying the Holleys suck, your just giving your experience as I have given mine. You dont like them and thats kool, I would run nothing BUT a Holley.

    Sparky, I have the cam in the correct position and I think it is the appropriate one. The shudder comes when you BARELY crack the throttle. In fact I am beginning to think that the shudder may be there all the time at anything under part throtlle where the jets come into play. I will have to go out and listen to it in a bit if I get to feeling better. I think it sounded strange even at idle. The more I think about it the more Im remembering that was odd. Before the new gaskets were put in yesterday I ran it leaking all over briefly. It did get warmed up good, and it seemed fine. Now it has that the shudder. It has got to be something in the metering block.

    502, thanx for the explaination of the power valves sizing. That has always been a grey area of tuning I couldnt get a grip on. And thanx for saying takes time to fiddle w/ it but once its adj. right you wont have to mess w/ it.

    If ya can't stop.......Smile as you go under! [​IMG]
     
  14. Thunder

    Thunder 3/4 ton status

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    Re: The

    OOps It was a little late when I was on last night guess thought I read 4160. Also ment to say meetering block instead of Valve body.
    I really wasn't putting down holleys but they do take some tuning to make them work. Every Q jet I have bought has been pretty much plug and play.Unless it was on a built engine.
    I ran and tuned Holleys and AFBs all my life. And I do agree I dont think there is any carb that can be as easily tuned to run as good as a Holley. They are a good street carb
    But for hard offroad use nothing except FI can beat a Q-jet
    I live in the most mountainous state in the nation.Because I like them, I have tried many times to modify Holleys to make then dependable in the steep terrain I drive in but have had no luck making them run better than a Q jet.
    As long as you keep Holleys in the flatlands or little hills(under 6000 ft) they do fine. Just try to take one straight up a steep mountain from 6000 feet up to 10000 feet and tell me how great Holleys are. If you make it. I have had Holleys flood out or dry out the jets on me too many times and leave me in tight spots, on very steep terrain to ever trust one again.
    They just dont fill my needs for a offroad carb. But I still think they are a Great carb. And for most uses they will work very well

    <a target="_blank" href=http://coloradok5.com/gallery/Thunders-Blaze>http://coloradok5.com/gallery/Thunders-Blaze</a>
    <font color=blue>NEVADA: Where the pavement ends, and the West begins.</font color=blue>
     
  15. shupach

    shupach 1/2 ton status

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    Re: The \"hated\" Holley carb!

    i can get a manifold adapter, im running a holley street dominator intake. but wats the average cost of a good junkyard Qjet and which one is the best for a 400 and how do i identify? sorry about all the questions.

    phill
     
  16. Pure Insanity

    Pure Insanity 1/2 ton status

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    Re: The

    HEHE! I reckon I should have stated long ago that I live in Fla. and there are few if any hills here. [​IMG] I have done some steep climbing before w/ it. Hard to judge but poss. 250 feet at about a 60deg. incline. Maybe I have just gotten lucky, and got one that responds to the mods well.

    If ya can't stop.......Smile as you go under! [​IMG]
     
  17. K5RON

    K5RON 1/2 ton status

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    Re: The

    Sorry for getting off the subject of this thread, but I tend to agree with Sparky. Sounds like a slight "lean" stumble. Upon cracking the butterflys, manifold vacuum drops and a big rush of air enters the engine. The accelerater pump overcomes this "lean" condition. I would tend to look in that direction, if in fact it is the carb!


    Ron


    '84 K5......Tree Fitty, SM465/Np205, D44/14BFF, Pro-jection! .....and of coarse no other color than Odie!
     
  18. Pure Insanity

    Pure Insanity 1/2 ton status

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    Re: The \"hated\" Holley carb!

    I REALLY would not recommend using an adapter to get a spread bore onto a square bore. You are basicly creating another venturi. How far built is the 400 you have, If its fairly stout Id say look for a 454 Qjet. If its stock get a SBC Qjet.

    I really have doubts on the adapter, if you were going to put a sq. bore on a spread bore thats on thing but, shrinking the secondaries like that may cause problems. I have never done this so I am not sure how it will work. It just seems like it would be a problem.

    If ya can't stop.......Smile as you go under! [​IMG]
     
  19. Pure Insanity

    Pure Insanity 1/2 ton status

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    Re: The

    Well I listened to it again. It IS shuddering even at idle. It sounds like the right side is good and the left is not. Which makes sense that the left side idle adj. is not doing anything. It is running at idle, its just not real happy about it. [​IMG] 1/2 the motor is running correct, the other half is being more or less drug around by the stronger side, causing the vibration. The shudder is best descibed as a bad plug. (but it is not a bad plug) As I said if I go to WOT or anything above idle or fast idle it is fine and smooth. It has GOT to be in the left side idle mixture. When I say just off idle, Im talking hardly a difference in RPM, just off idle. The shooters are coming in right off the bottom when the throttle is cracked, so I will assume that the cam is correct. BTW I forgot to mention it has a 30cc primary and 50cc secondary acc. pumps

    In a while I will have to go pull it off, and open it back up.

    If ya can't stop.......Smile as you go under! [​IMG]
     
  20. shupach

    shupach 1/2 ton status

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    Re: The \"hated\" Holley carb!

    maybe i should skip these complications and just rejet the the carb, cause the last thing i wanna do is put another intake on it, the engine has stock running gear(pistons, crank) i bought some reconditioned cylinder heads and supposedly an RV cam, its more like the stock v8 cam for the 88 350. and then i put a new carb and intake on it. its running rich(black stuff on inside of exhaust). so i figure ill just rejet it, its for mud neway so ill be in the high rpms.

    phill
     

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