Holley vacuum secondary not opening 3L SBF, Dart SHP 8. This is normal while the engine is not under boost. because they are clueless about how to actually set up a vacuum secondary Holley. 470" forged steel crankshaft & H-beam rods, Wiseco 4. when I race the car on the street at wide open throttle and approaching 6000 rpm, I would expect the vacuum secondaries to open fully with that setup. 200" forged pistons, Trick Flow Twisted Wedge 11R 205 CNC Comp Ported heads, 12:1 compression ratio, 232°-244° duration/. Unlike mechanical secondaries, which open based on the position of the throttle, vacuum secondaries operate using engine vacuum to control their opening. I put the carb on the car, started fine, idles fine, runs at any speed as long as I didn't get on it too hard. If the carb is to small shouldn't it open the vacuum secondaries all the way open? At 5,000 rpm with the lightest spring the vacuum secondaries are just beginning to Jul 7, 2014 · Air filter shouldn't have an impact on secondary opening. The more air that flows through the primaries the more vacuum is applied to the vacuum diaphragm that opens the secondaries. I unhooked the secondaries and then drove it to see if it made a difference and it didn't. I would like secondarys open earlier so I cant feel them, or have to wait for Nov 25, 2024 · More importantly, Holley offers several different color springs that are the main tuning tools for changing the secondary opening point. I have a 750 holley vacuum secondary on it now. Blower belt comes off or slips. But still don't see vacuum secondary's being your problem with Norm walks you though how to properly adjust the secondary circuit on a Holley 4 Barrel Carburetor. Then I checked the vacuum secondaries. I've tried everything including changing out the return spring, blowing out the vacuum port, etc. 200" forged pistons, Trick Flow Twisted Wedge 11R 205 CNC Comp Ported heads, 12:1 compression ratio, 232°-244° duration . A vacuum secondary carb will allow you to run the primaries harder because you can control the opening of the secondaries. If you feel a change in acceleration when the secondaries open, the spring is too stiff and the secondaries need to open sooner. TRUCK AVENGER™ CARBURETOR P/N 0-90470, 0-90670, & 0-90770 INSTALLATION, TUNING, AND ADJUSTMENT MANUAL 199R10268-4 NOTE: These instructions must be read and fully understood before Sep 16, 2013 · The presence of an air cleaner restriction increases venturi vacuum and causes the secondaries to open sooner in all cases. It feels very well. By all means you can strong arm the linkage and close them a few thou. It is running at about 19" of vacuum at idle. Mar 2, 2004 · From my experience with vacuum-operated secondaries on Holley carbs, the usual culprit is lack of vacuum either due to a torn/non-sealing diaphragm, blocked vacuum port in the secondary bore, or torn/missing cork gasket between the main body and the vacuum secondary diaphragm unit. A Jun 14, 2021 · Holley 600 vacuum secondary which sold on ebay. READ the directionsdifferent color springs are different opening rates. I have verified the secondary's won't open. Some of the old Holley secondary vacuum canisters used a steel check ball inside them, people would remove the steel ball and the secondaries would just flop open and cause a bog as soon as the they opened. I was reving the engine by hand I noticed that the secondarys were not opening. I did that test where you put a paper clip type device on the actuatory arm and then go drive the car at wide open throttle, and then look to see if the paper clip moved, and it didnt. looks great but anyway the first clue that things were not right on the Quick Fuel was my external vacuum gauge (cowl induction hood) Oct 14, 2008 · Most books on Holleys I've read and instruction sheets from Holley which accompany their secondaries spring kit distinctly say to NOT remove the check ball or the action of the secondaries will be too abrupt in opening or closing. --> Would a lighter pressure spring on the vacuum secondaries allow them to open further? Also there is a linkage that comes from the main throttle lever on the carb and looks like it prevents the vacuum secondaries from opening until the main barrels open Jul 16, 2024 · Another issue with the later 3310 carbs and some of the later VS variants, is the lack of vacuum secondary feed tube protruding into passenger side primary venturi, later versions only have a hole in venturi wall which causes later opening and/or lack of fully opening secondaries. I checked for vacuum leaks and did tune up with plugs and wire. ported vacuum - either you have a serious vacuum leak somewhere, or the linkage isn't connected Jun 7, 2012 · Please be aware that this is a community forum. 1 3 of 4 Go to page. Oct 29, 2021 · When you put a heavier spring and it ran a bit better may be a clue to the solution. A spring assortment kit, Holley P/N 20-13, is available to help you "tailor" the secondary opening rate to your application. If anything, a free flowing air filter would assist an engine to get lower vacuum readings. I need some advice on what to look for. Learn the critical role these components play in fuel delivery and how their misalignment can lead to performance issues like bogging and stalling. Air responds instantaneously when the throttle plates open. The video describes the various rate secondary springs, how to change them, and the testing procedures to follow to make sure the secondaries open properly for best performance. Joined Dec 17, 2012 Jul 31, 2023 · If the vacuum signal from the engine is insufficent to open the secondaries , they will not open , it only takes about 20 HP & very light throttle to MAINTAiN 3500 going down the road , the secondaries shouldn't open , in the driveway , you'd run the risk of blowing the engine to get them to open ! Dec 2, 2009 · Holley offers some tips on how to properly operate and adjust four-barrel carburetors with vacuum secondary throttle blades. Apr 3, 2006 · On a friends sbc he has a Holley 4 barrel with vacuum secondaries that open only about 10-15% at max pedal. Mar 30, 2020 · Sniper EFI Tuning & Tech. Is there a way to test it without a vacuum pump? Aug 28, 2006 · The vacuum secondary spring is the Holley "yellow" which is the lightest fastest opening spring they offer. My secondaries are not opening up while driving. My thoughts are if you tried to set them up to open progressively Dec 6, 2024 · What Are Vacuum Secondaries? Vacuum secondaries are a feature found in many Holley carburetors designed to improve performance at higher RPMs. When the vacuum is low enough in the primary side the secondaries will open. Indicators include a lack of power and the secondaries not opening as expected. 020" higher then the front, so don't try to equal them as it will create other issues. I took it apart, and it look new, very soft. If the primary set screw is backed right off. The secondarys are cracked at idle so as to not bind the plates in the bore. Holley's materials state that the check ball is only used in carbs in which the check ball sits on a hole which has May 29, 2008 · I get no different in fuel mileage between my 650 custom holley vacuum secondary carb with a billet base plate identical to the quick fuel cast base plate that the slayer uses and also my current 600 holley older zinc 80457 with a secondary metering block and the same size ifr and jetted the same as my other custom holley 650 carb I use during Mar 31, 2016 · When your throttle is closed, the linkage blocks the secondaries from opening. Apr 20, 2023 · On your Monte Carlo I would buy a spring kit and try a yellow spring if your current purple spring does not open up fast enough. I've put a cable tie around the secondary diaphragm plunger to see how far they are opening and after a fast run down the road it appears that they are not opening at all. Mar 23, 2018 · I have two Holley 4bbl carbs on my engine. Jul 7, 2006 · If the secondaries are working as they should, you should neither hear nor "feel" the secondaries open. Im looking to get a different carb seems to be running lean and im not sure if the vacuum secondary's are opening. How To Adjust The Secondary Speed Screw On Holley Carbs - Holley Motor Life Aug 9, 2005 · C1 & C2 Corvettes - Secondaries not opening up?Why? - I have a stock Holley 4160 carb on my ?66 (it is a later replacement, but the stock style). The video describes the various May 2, 2024 · I have a Holley 4160 750 cfm vacuum secondary carburetor on my Chevy Camaro with a 396. Nov 16, 2008 · To Vacuum secondary or not to vac sec. Jun 2, 2021 · Yep, I always check it, frequently needs to be bent a little longer to make sure it closes the secondary . This was possible because there was no secondary idle circuit. I can manually manipulate the vacuum plunger and get them to kick in and there does feel like there is diaphragm resistance Nov 15, 2013 · 1980 - 1986 Bullnose F100, F150 & Larger F-Series Trucks - Holley 4180C - Vaccum Secondaries - How can one tell if the vacuum secondaries are opening as they should? I recently rebuilt this carb, but the truck seems low on power. Although Holley employees will take part in answering questions from time to time, your questions may or may not be answered by Holley personnel. It does pretty good for cruising but when loaded I have to get the rpms up enough for the secondaries to open. Any ideas how to over this. Secondary spring kit: https://amzn. Works pretty well, but even after fiddling around with different springs, there's still an obvious delay on the secondaries opening. . Secondary on carb(s) not opening. 31 Posi Vacuum secondary only open proportional to the RPM an engine produces. The belief that vacuum secondary carbs open and only allow in the air the engine asks for without restriction is May 22, 2011 · Correct shaft length. Refer to “No high RPM or top end power”. It should return to the closed postion in a controlled manner, if it just flops closed the secondary diaphram is probably the culprit. Feb 4, 2023 · With now knowing it does move freely, but not opening while "testing", I would say you need to look into a spring kit and then test/tune swaping springs until you get your desired results. (bigger jets, fixed the gas leak. (Had some good aiflow mods too. 070 primary idle air bleed difference and . BuzzLOL · Cars, Trucks, Boats, Motorcycl. That should be the first thing to get that should help you out. May 3, 2014 · The Holley secondary springs regulate the opening point and rate on a vacuum secondary Holley based on venturi air velocity. I'd rather have a douple pumper so if I push the throttle enough I can open the secondaries at a lower rpm. Engine has vacuum at low RPM. The secondaries should open some, even if no vacuum, when you open the Aug 14, 2020 · Most books on Holleys I've read and instruction sheets from Holley which accompany their secondaries spring kit distinctly say to NOT remove the check ball or the action of the secondaries will be too abrupt in opening or closing. Most of the vacuum sec carbs do not open the secondaries all the way, and some don't open them at all. The Qjet was rusted internally and even after the rebuild it didnt operate correctly. I tested the vacuum actuatory off of the car Feb 14, 2019 · You're not going to get full opening on the secondary's until you get it revved up. May God's grace bless you in the Lord Jesus Christ. If you feel a bog, the spring is too soft and allows the secondaries to open too early. Blower drive belt is slipping. I pulled the secondaries vacuum linkage from the Mar 28, 2021 · A lot of folks never touch this stuff, but it really does make a big difference. Enough springs to help you pick where you want the secondary's to open for your engine or tune up. Dec 3, 2012 · HERES WHAT THE HOLLEY TECH GUYS SUGGEST "The Holley secondary springs regulate the opening point and rate on a vacuum secondary Holley based on venturi air velocity. After putting in my low restriction X-treme top, my car runs better, but my secondaries open less. Mar 9, 2023 · There are several reasons why your Holley vacuum secondary might not be opening. Right now I have a Holley 670 Street Avenger on my 302. The carb main body is one of those racing style Proform bodies with vacuum secondary ports. Aug 10, 2007 · Fuel Injection, Carburetion & Fuel System - Secondaries Won't Open on Holley - I put a new Holley 600, vacuum secondaries, on my Windsor a few days ago and I got it running good. Jul 19, 2015 · 2400 lb car. Oct 26, 2017 · I have 396 BBC with a Holley 3310 Vacuum Secondary carb. secondary spring pressure. I used to get 300+ HP from a 351C with a torque cam and 600 cfm Holley vacuum secondary carb, yet get 19-20 mpg in the highways. My vacuum secondaries are hardly opening with the lightest spring installed. Mar 20, 2012 · I've fitted a brand new Holley 1850 carb on my 302 engine. Manifold vacuum drops down to almost zero when the throttle is at WOT. Feb 11, 2012 · When possible in a street build, I really like the thunder series Edlebrocks and typically use the 650cfm size--even on a mild big block. If they are opening, the clip has to be moved to a lower position after the ride. The engine must be under a load. Jul 31, 2023 · About Press Copyright Contact us Creators Advertise Developers Terms Privacy Policy & Safety How YouTube works Test new features NFL Sunday Ticket Press Copyright Nov 22, 2024 · Problems with the secondary throttle plates can limit your engine’s performance, especially at higher speeds. Mar 30, 2009 · Hey guys. Today I'll be showing you guys how the vacuum secondary system works on a holley carb. Do not remove the check ball. Understanding Vacuum Secondary Springs. Otherwise, while you're sitting there idling, the throttle plates could open on their own (via a vacuum signal). to/31rYTQ0quick change diaphragm: https:/ on the secondary side of the carburetor it is necessary to graduate the secondary-opening rate. Sep 11, 2004 · A 750 Holley will still open the secondaries on a 305. I wanted to determine 1) if my vacuum secondaries were opening, and Jul 4, 2011 · Typically. Jul 13, 2006 · The engine is a stock 350 in my son's Chevelle-nothing special. Holley 20-13 Holley Vacuum Secondary Spring Kits | Summit Racing May 20, 2002 · The opening rate of a vacuum secondary system is controlled by the diaphragm spring located in the vacuum secondary diaphragm housing. I know this is a common problem for holley's and I've done some research on a solution and have not been successful. The power valves should be picked based on your vacuum as the secondary's are opening up. Holley's chart shows that for a 350 SBC, the Orange spring won't reach fully open until 5680 rpm, and the Yellow at 5750 rpm. I checked the secondaries and found they would not close all way. Here are a few of the most common causes: Clogged passages: Dirt and debris can clog the vacuum passages in your carburetor, preventing the vacuum secondary from opening properly. Final Thoughts. Now, secondaries that use vacuum to open. Vacuum secondaries open under engine load, so if they do open by winging the throttle then they will most likely bog the car when it’s accelerating under load. All Holley vacuum secondary carburetors are shipped with the heaviest black spring in the secondary canister. The engine pulls 18in vacuum at idle. Linkage binding. Nov 3, 2024 · Unlock your engine's potential with our comprehensive guide on adjusting vacuum secondaries in Holley carburetors. Also, do not try to run without a spring in the diaphragm housing. The transfer slot in the rear sits up . 044 idle air bleeds . This particular carb is a holley 80457S vacuum secondary aluminum main May 4, 2013 · The vacuum secondary pot references the vacuum in the primary side of the carb, no vacuum lines are used for that, it's an internal passage. May 6, 2014 · Yes, a 600 cfm will be good for 300+ HP easily. When I open the throttle by hand under the hood the secondaries move freely. The carb is a Holley 1850-2 600 cfm vacuum secondary. Blower displacement is too small for application. Its the stock holley 4150EG. What you want to be looking for is keeping the primary side open enough to keep a square transfer slot opening, and also have the rear open up just Jul 15, 2018 · I figured out why most Holley vacuum secondary carbs have the reputation for making less power than the equally sized double pumpers. Feb 12, 2006 · Hi TC, I bought a brand new Holley 4160, vac secondarys, from summit racing and I put it on my 396. how much is required before your forced to have mechanical secondary's? im looking into a holley or a demon carb. Below is a chart on the spring colors and the rates shown are just a generic starting point and builds will vary. The car would always idle fast. The thunder series is based similar to the Holley vacuum secondary as it uses air speed to open the secondaries and buth are tunable on the secondary side for the opening rates. I can blow compressed air through the primary and open the secondaries in my driveway. Secondaries open when we manualy hook them up to the main throttle shaft. The drawback is that you don't have an accelerator circuit for the secondaries, so when they open Apr 15, 2008 · Re: vacuum vs mechanical secondaries First, there are no differences in the primary sides of a 750 vac secondary and a 750 double pumper Holley. 033 ifr in blocks. I guess its possible to put too light of a spring under the diaphragm and have the secondaries open prematurely. The spring holds the diaphragm so it will not open the secondaries. If you do have a vac. ) Aug 19, 2003 · Also you will not see gas being squirted when you open the secondaries. Fuel delivery problem. Jul 25, 2007 · I'm thinking of doing just that. What caused me to ask the question was the fact that I monitor how much my secondaries open via a zip tie on the shaft. Also, you want the secondaries open enough as well, but not too much. Vacuum secondary diaphragm problems arise when the diaphragm is damaged, or the spring tension is incorrect, preventing the secondaries from opening smoothly. I Sep 28, 2022 · The vacuum secondary uses venturi vacuum from the primary throttle bores. I Aug 25, 2010 · On my vacuum gauge at idle it reads 15 in of vacuum and at wide open throttle it drops almost to zero. Vacuum Secondaries or Mechanical Secondaries it doesn't Oct 13, 2009 · A bog typically happens when you open the secondaries too early. , that is the question. We used the lightest spring and they will not open. I have a Holley Street Avenger Carburetors 575 carb on a non-modified 292. They are same and work the same and if you don't get the secondaries open, will get the same mpg. Here is the issue: Slam Dec 30, 2002 · 425 hp is 425 hp, whether or not you make it with a vacuum secondary carb or one with mechanical secondaries, DFI or a 2-bbl. An older neighbor (who's elevator doesn't seem to go to the top floor on some days) who was Dec 12, 2008 · If you can feel the vacuum sec's open they are opening too soon. No effect. Thanks . I'm new to carbs so keep that in mind. This rod attaches to an elongated hole on the secondary shaft (see photo). Locate it in the upper portion of the rod and test drive your car. You're probably thinking of mechanical secondaries, i. Nov 27, 2024 · I have a Holley 80805, I did a complete rebuild for the exception of the vacuum pump, because the diaphragm was not included in the kit I purchased. I've removed the vacuum canister and confirmed it is functional. A "lighter" spring will allow the the secondary throttle plates to open more quickly. Vacuum sec carbs are an on demand carb so if you have too much carb to begin with they won't open as much. So as a temporary fix I zip tied the linkage to bypass the vacuum. May 9, 2006 · Help my vacuum secondaries on my Holley 4160 carb won't open. The primary is an 1850 600 cfm, and the secondary is an 8007 390 cfm. Dec 16, 2012 · Holley vacuum secondaries won't open. The vacuum secondary pull rod is extended all the way down. I like vacuum secondary types because they drive better on the street and give better mileage in general, and works fine in my experience. I don't have much experience SECONDARY DIAPHRAGM SPRING KIT P/N 20-13 For models 4150 & 4160 Vacuum Activated Secondary Carburetors INSTALLATION & TUNING INSTRUCTIONS 199R8219-3 INTRODUCTION: This kit contains a variety of secondary diaphragm springs to tailor the secondary opening characteristics to a particular engine and vehicle configuration. Secondary open on demand when the motor needs it. Also is a video on how to see if your vacuum secondary is opening up all the way. Holley 600 vacuum secondary 1850-3 same as above but with just the . Nov 22, 2016 · I have great vacuum according to the gauge and it hasn't changed from before. If you wan to speed up flow, (you don't need this mod with your carb and engine size) you can take a phillips screwdriver and tap it lightly with a hammer to make 4 slots underneath the checkball. I don't have a vacuum pump. Holley 670 street avenger vacuum secondaries. The vehicle is a 1983 GMC 6000 school bus, and the engine is a 366. Performance is compromised less by holding the secondaries closed a little too long than by opening them a little boo soon. When they open too early, the vacuum signal through the whole carb drops and the engine speed and power drop for a few seconds, then as the engine speeds up to make use of the additional CFM available through the carb it accelerates again. 074/. 623" lift/114° LSA H/R camshaft, Trick Flow R-Series FTI Comp Ported intake, BBK 80mm throttle body Jun 21, 2019 · If you remove the secondary vacuum unit from the carb to get the lid off (which is typically necessary) - don't forget to make sure the little cork o-ring that seals the vacuum port to the carb body is in place or you will have a small vacuum leak and the secondary's will not open. I'm thinking such a light car, 3:55 gears, standard tranny, light This is the Holley carb that I use on my wood gas fueled Chevy 350, it rarely sees gasoline flowing through it but this truck is old school in how to convert Jan 29, 2013 · I use this truck to tow a good bit and just cruise around. If you have the proper converter or can leave at the proper rpm for the camshaft to be in its operating range, anytime you can run a double pumper run a double pumper. Dec 2, 2009 · How to properly adjust the secondary speed screw on Holley carbs. Thus, Holley can not guarantee an answer or timing on an answer. Rev it all you want in the garage the sec's won't open. 1971 Chevelle SS454, T56 Magnum 6 speed, 3. I adjusted the stop they still won't close. 350 chevy engine, 350 turbo automatic, 4:56 rear end. May 2, 2023 · The original Holley vacuum secondary carbs had a small low speed air bleed (LSAB or idle air bleed) in the secondary (~. The secondaries will not open under any circumstances. i shined a lite through it and saw light. 030) to help the secondary main start flowing quicker at large throttle opening. Jul 8, 2020 · C3 Tech/Performance - Holley vacuum Sec opens to late - Hello My Holley Street Avenger 870 have vacuum secondarys. Apr 15, 2020 · I'm troubleshooting a 600 cfm remanufactured Holley with vacuum secondaries. 4 hole spacer ran like a charm and very clean and snappy. a Holley double pumper. Or, in actuality, lack of vacuum. I have the quick change tops on the vacuum secondary diaphragm housings for both carbs, and they are linked together with a vacuum hose. I can rotate the shaft and open the secondaries slightly when sitting at idle position causing the increase in rpm. Too Aug 11, 2012 · Note, it is a Holley 3310. We bought a Holley quck change kit. e. The only way to tell if they're opening or not is to have someone watch the linkage as you're running on the lake. That little ball that is suppose to be in the diaphragm is missing. are your holley vacuum secondaries working? here is how to test them in several different ways Jan 12, 2002 · One way to check if the secondaries are opening, that has worked on my 600 vac secs, is using a paper clip on the diaphragm rod. The secondaries must not open until the engine requires the additional air. You also can't test them with no load on the engine. Try an even heavier spring and see what happens. I used the paper clip on the linkage and it didn't move. When properly tuned and maintained, the Holley 670 Street Avenger carburetor offers robust performance. Apr 10, 2019 · Vacuum secondary carbs demand sufficient air velocity through the secondary side as the throttle begins to open in order to stimulate fuel flow from the secondary boosters to prevent hesitation. Nov 20, 2004 · With the engine off open and close the secondaries, it should move smoothly and you should hear the air going in and out of the vacuum secondary diaphram. Jun 9, 2001 · Vacuum secondaries don't actually open based on manifold vacuum (which drops to almost zero at wide-open throttle); the vacuum which overcomes the spring pressure in the diaphragm to open them is created by increasing air velocity through the primaries passing by an orifice connected to the diaphragm housing - the higher the air velocity, the higher vacuum created in the passage, and at the Jan 31, 2002 · So I think they are not opening all the way. What causes the secondary to open is the air traveling threw the venturi in a carb. you adjust curb idle rpm on the primary side. The application of power through the RPM range should be linear and smooth. The secondaries don't always open all the way, just enough to "feed the need" based on the engine specs and the spring you have installed in the vacuum can. DarrelG, the secondaries won't open if your under the hood and blipping the throttle, the motor has to be under a load. Jump to Latest 41 - 60 of 66 Posts. I figured out how to fix this issue, and YES, you can open the secondaries real early without a bog. Realized that the secondaries weren't opening. This is a 1979 Holley 2818-1 with vacuum port for vacuum canister on the metering block. Only a mechanical secondary carb will have an accelerator pump like the primary side. I bought a new diaphragm but when I pulled the housing off before splitting it open, I checked it with my vacuum pump/gauge and it works. Jun 28, 2005 · Have a question for anyone that knows Holley vacuum secondary carbs. 4. When I open the throttle by hand, I can open the secondaries and they move freely. This procedure is only used on engines with large duration camshaft that have very low vacuum at idle. For best performance, you should not “feel” the secondaries opening. Oct 14, 2020 · We show you some simple tip and tricks to troubleshoot and fine tune you vacuum secondary Nov 30, 2002 · I just discovered that my secondaries on my 750 HP are not opening, or not opening all the way. Apr 26, 2017 · I have a 18 year old Holley 770 Street Avenger vacuum secondary. I tried the paper clip trick and the secondaries are not engaging. A trick to see if the secondaries are opening is to put a paper clip on the secondary linkage. '92 Ford Mustang GT: 385"/6. 623" lift 114° LSA H/R camshaft, Trick Flow R-Series FlowTech Induction Comp Sep 13, 2024 · Holley sells a kit with about 7 different springs in it. That is because vacuum secodary carbs do not have accelerator pumps like the primary does. 031/. Dec 20, 2022 · A Holley vacuum secondary not opening? In this article, we’ll be exploring the six most common causes, along with some potential fixes you can try out. If you “feel” the secondaries open, do not confuse Nov 21, 2020 · If the little seal between the main body and the vacuum diaphragm is not sealing, the secondaries wont ever open. Jun 20, 2017 · Opening the secondaries early causes the situation described above. 002 smaller on secondary at . This allows torque to increase along the peak torque curve. Replaced the Qjet with this VS750. I've been doing a lot of things to the 331 to get it tuned in and decided to check the secondaries on the carb today. ) But the secondaries are not opening. check for a vacuum leak before playing with the secondary stop Nov 10, 2024 · Synchronizing the secondary operation by ensuring the vacuum secondaries open at the same rate will help maintain consistent performance across all cylinders. Anything I can try Dec 3, 2022 · Mild 454 with good manifold vacuum. When dealing with a vacuum secondary carb, keep in mind that they will not open in park or neutral. Engine won’t rev very high. The carb has been rebuilt and works fine other than this problem. I've had mechanical secondaries in the past and just want to know how I can be sure the secondaries are opening (fully) with this type of carb. When the engine is Nov 10, 2016 · I have a 4150 with vacuum secondaries. 7. Worse yet is the guys who put a screw in the slot on the other side of the link, using the link to force the secondary OPEN, using that link to yank them open when the primary moves far enough . Full throttle runs 1st - 3rd secondaries not opening. but you have not addressed why the high idle if you still have primary adjustment. Oct 11, 2012 · FYI: The manifold vacuum has nothing to do with the opening of the secondary air valve or vacuum secondary in a Holley carbs. The engine pulls about 10-12 manifold vacuum. any recommendations or ideas? Jun 23, 2009 · I just installed a Holley 4160/3310, vacuum secondary. This heavy spring delays the opening of the secondaries. Have you replaced the diaphragm? Do you have a 4160 carb? Any modifications? May 17, 2021 · Don’t judge the secondary opening by revving up the engine in the garage. However, there is a delay before the fuel begins to flow. I think they opens to late, when I hit WOT it takes about 2-3 seconds before I feel the secondarys open. Aug 30, 2010 · this is attached directly to the secondary throttle plates and will open up around 2800-3200 RPM on most engines. Jun 29, 2016 · May God's grace bless you in the Lord Jesus Christ. Changed vacuum spring to the white one (lightest), only a slight opening by the paper clip test. You should not feel a bog or a change in the rate of acceleration if the correct spring is used. It is vacuum vs. Discover troubleshooting tips, from adjusting spring tension to fine-tuning the air-fuel mixture, to ensure optimal efficiency and Jun 21, 2010 · Re: Holley 4 Barrel, Carb Secondaries Not Opening You have a vac secondary 600, you'll never get the secondaries to open without a load, even running at the dock in N revving it. What should I look for to remedy this and allow them to open to what I believe should be alot more? It's like he is running a 2 barrel. secondary -- and you're not getting any secondary action that is based on carb. You do need to put a vacuum pump on the carb to see if you can pull a vacuum, and then open the throttle to see if the secondaries also open with vacuum applied. Go. Holley's materials state that the check ball is only used in carbs in which the check ball sits on a hole which has Holley offers some tips on how to properly operate and adjust four-barrel carburetors with vacuum secondary throttle blades. Explorer motor with TFS1 cam, Performer RPM Air Gap and Holley 570 Street Avenger with vacuum secondaries. 2 block, Eagle 3. I assume that this rod serves 2 purposes, 1 to prevent the secondaries from opening too soon and 2, to close the secondaries. 042. The linkage operates freely and by hand everything moves thru full closed to full open. Sep 16, 2010 · Its all on a chevy 350 w/ a performer intake. gptu nxp nkraol ivi lbwjr chqw ukpfyp fkfjt kwlh wyxxq vmgkmx dgm uiqtj ophzb gqoxg