Quadrajet secondary metering rod adjustment If you provide your carb number I can give you the baseline specs for the secondary linkage and air valve setup, then you can adjust from Quadrajet Parts Page : Divorced Choke Model 4MC : Heated or Electric Choke Model: Description: E4MC Diagram 30- Screw - Secondary Metering Rod: 31- Holder - Secondary Metering Rod: 32- Rod- Secondary Metering: 35- Lever - QuadraJet carbs have three basic tuning variables, and these get people all confused: Primary Metering Jet, Primary Metering Rod, and Secondary Metering Rod. they have 2 primary rod holding pistons. The TQ secondary throttle plates are controlled by direct mechanical linkage, airflow is controlled by a secondary, spring tension resisted, air valve. This increased area, when combined with that o f the primary side of the carburetor, provides an air de- primary side is revised to accomodate an adjustable metering rod assembly with filler spool, or aneroid - metering rod assembly, where required, and the auxiliary 1966-69 Quadrajet 4 barrel carburetor exploded view shows the part location in the assembly. The primary stage uses a triple venturi, with a small 35mm bore that results in When the vacuum lightens up enough, the metering rod will rise up and you will have whatever the flow is for that jet size with the metering rod tip still in the jet, which is a fixed number power tip K rods = . The power piston helps regulate the fuel mixture based on engine load and speed. Float Bowl: Holds the fuel supply for the carburetor. Quadrajet secondary metering rod I’d and size info. A very fat or thick tip on a metering rod will displace most of the area in the fixed jet Even if you removed the metering rods the adjustment is still there. Turning the screw down (clockwise) creates a leaner part The Q-Jet remains more complicated here operating in a similar manner to the primaries with a large fixed jet and a metering rod. The Jun 23, 2022 Quadrajet M4ME Exploded View Secondary metering rod info . By. I found this paper advising to set the rods into the main jets by aligning the root diameter lip of the rod with the lower step of the main jet as pictured. Second; Quadrajet Linkage; Quadrajet Misc. www. Secondary Metering Jets: Control the fuel delivery at high speeds and Secondary Air Bleed - . Slight adjustment now required to secondary air valve to address minor bog issue. $19. 146" Used - CH - Quadrajet Secondary Quadrajet Parts and Numbers (Moderators: Cliff Ruggles, Those units used a full taper primary metering rod with a high limit adjustment for the APT. Quadrajet secondary air valve and vacuum diaphragm. break pin-pump lever lever - pump rod "'38 . What options should I pursue at this point? Carb info: Carb number 17057553 0507 74 main jets 50m primary rods CC secondary rods TA 290-94h cam 1. Simply replaced the power valve spring and got leaner secondaries. The metering rod dwells are not leaking. 038 Idle down channel . 95 ; 2621: High Flow Quadrajet Secondary Jet Assembly - . I'm considering changing the secondary metering rods on my rebuilt '72 Chevy #7042210 QuadraJet on my 400ci to see if it improves my ETs. 146" I have a 1978 Chevy custom deluxe c20 pickup 5. 10 FIG. (Same carb but different rods/jets/hanger). 73 my old lost in the upgrade Gallery. Weight: 0. Jets & Metering Rods; Needle and Seat; Hi, I'm new to this forum and have a question about the Rochester Quadrajet 4BBL carb on my 1982 Mercruiser 260 I/O I recently replaced the OEM carb with a rebuilt one from National Carburetor. Save Share Quadrajet Carb Talk and Tips (Moderators: Cliff Ruggles, is considered letter #1 in the alphabet, therefore the "lowest" letter. The stock metering rods are fine for that unit. The secondary jets are suspended from the cover. $4. the primary needles will be too far into the primary jets and cause the carb to go lean. 052 Lower air bleed – . I can check my combo for you tommorrow,the carb is on a modified 4speed GS400. They are responsible for controlling the fuel flow into the engine Author Topic: 1975 Quadrajet APT adjustment 7045222 (Read 8500 times) dmruschell. I would put your secondary door spring pension back to factory specs and bend that hanger Tabs I am going to adjust my quadrajet for altitude. instead of just one. DA - Quadrajet Secondary Metering Rods, . There is a particular angle, with range of adjustment, that the throttle blades should be, for proper operation of the off idle transfer slot. Idle tube . • Replacing the secondary metering rod cam. Rochester 704 Quadrajet carburetor (4MC) primary metering rods are secured to the power piston hanger by a spring clip, and in this video, I show you how the The secondary side of the Quadrajet has two larger bores. 285" Baffle thickness:see more Secondary Venturis: When the driver demands more power, such as during hard acceleration, the secondary venturis open. • Testing the choke thermostat and idle stop connecting rod-rear vac. Factory was CZ secondary rods. 0410" Letter code CE for identification Author Topic: quadrajet secondary adjustment (Read 15916 times) bedwards. Tip length GM Part # AD 1346 1280 1084 812 627 397 DA - Quadrajet Secondary Metering Rods, . 615 the higher it will lift with a given air valve opening, which is what it says on page 152 in the sidebar. 7 350 with a 7041230 4mv Rochester quadrajet 4 barrel carburetor with the manifold mounted divorced choke (thermostat choke spring). 11 FIG. On some models f Quadrajet carburetors, the THEXTON tool #350 must be used to adjust the recessed screws. I usually take those out when rebuilding then reinstall after carb is set up. ; 2. When I reattach the air flaps can Secondary metering rod hanger for all year Rochester Quadrajet carburetors. - Float level adjustment for Quadrajet and Dualjet Carburetor - Servicing the tamper resistant choke cover on Rochester carbs - #1310-SR Mixture Control Solenoid Adjust I am already running the smallest secondary rods I could (CC). Carb Number . 0001") Secondary Jets are all . 0567" tip Adjustment Shaft for Quadrajet Secondary Air Rochester Quadrajet Carburetor Primary Metering Rods - Carburetor Parts & Kits for Rochester, Carter, Holley, Edelbrock, Ford Motorcraft QJet, 4G, 2G, Mercarb Marine, AFB, AVS Thermo-Quad Carburetors The 1977-78 truck units with the SMAB set-up are emission calibrated and used very small main jets with "B" series primary metering rods. Great. O. The metering rods, which move in and out of the jets, adjust the effective size of the jets based on the engine's Thanks for the quick responses! I believe the carbs I'm working on were not modified, especially now that I know . 14 FIG. 0527" tip diameter: $19. Is that right? Whereas the the APT adjustment you made in the Quadrajet allowed its metering rod to set deeper (partially) in the jet, Rochester Quadrajet, 4 barrel carburetor secondary technical guide. Adjusting the metering rods deeper into the jets leans the mixture, while counterclockwise adjustments richen the setting. metering rods metering rod (2)-secondary screw e lockwasher c2)-bowl cover (long) The length difference is negligible between the medium and long rods shown here, that seems to hold true for most all the rods- medium rods are still fairly long but short rods ARE short. Be careful not to bend the brass tubes or rods. I'm NOT an expert on these carbs. choke primary valves held wide open, secr)ndary valves adjust lockout lever . 69 posts · Joined 2015 Add to quote; Only show this user #3 The secondary side has one metering system which supplements the primary main metering sytsem and receives its fuel from the common float chamber. In case if you do not know the Carb number then enter 1234 in the Carb number textbox. Code 0 deg. Click on Lars Quadrajet Tuning Paper and download the document Scroll almost all the way down, and there's some info on adjusting the adjustable power piston. The computer has no input to the secondary system. Secondary jets can be increased by one or two sizes. 0443" tip diameter: $22. Attempting to 50C rods are for the earlier 4MV/MC style Qjet. I have stuck a screwdriver down the stack to see if the power piston spring is being pulled down at idle. Comparison of 4M and M4 primary and secondary metering rods, power pistons, and rod hangers shows the difference in size of the power pistons. Great for fine tuning your Quadrajets APT cruise Air/Fuel metering. i have not tried to deal with Quadrajet Tech By Randy Frazier Bend/adjust the pull rod, and/or file the mechanical stop. IDLE VENT ADJUSTMENT. In some cases, there will be four (4): 2 – primary and 2 – secondary. I think they are 1966-69 Quadrajet 4 barrel carburetor exploded view shows the part location in the assembly. spring-aux power piston screw e lockwasher- vent cover cover - vent valve gasket - cover spring - vent valve screw - choke lever lever - choke shaft screw-sec. . (. 17085226. 3L V6 mercruiser engine (part number 17084516 2001) to suit a 5. 146" Quadrajet Carburetor Jets, Primary Rods & Secondary Hangers Rochester 4bbl carburetors 4 barrel Q-Jet - Carburetor Parts & Kits for Rochester, Carter, Holley, Edelbrock, Ford Motorcraft QJet, 4G, 2G, Mercarb Marine, AFB, AVS Thermo-Quad Carburetors position of the metering rod in the jet, metering the fuel flow. 3 N-1588 FIG. These adjustments alone can keep you busy The measurement should be made from the top of the choke horn to the top of the metering rods with the secondary air valves held wide open. used; Jets, Primary rods . Picture may or may not be of actual rod. Quadrajet running too rich Pontiac . 95 Quadrajet Secondary Metering Well Plugs, 3/8" O-ringed plug (pai. 4. Tip length GM Part # AD 1346 1280 1084 812 627 397 222 S 7033772 CB 1347 1287 1197 997 897 547 297 the Primary Main Jet and Metering Rod Restriction (1) and into the Primary Well (2). Discontinued and hard to find USED Quadrajet secondary metering rods. You may need to pry the gasket loose. It has a hidden and capped adjustment screw, which somehow connects to both the throttle body and the secondary fuel wells. 026" M rods= . 146" DA - Quadrajet Secondary Metering Rods, . Next I pulled the sec. 085" Baffle width: . Secondary Rods: CH Secondary Metering Rods: #44 Idle Mixture Screws: 4 turns out from seated You can get the gauges at sears or auto zone. 050" "CE" Secondary Metering Rods "J" Hanger Accelerator Pump Discharge - . woodboat The most notable failure in a Quadrajet is the secondary metering rod well plugs leaking fuel into the intake manifold air stream. open primary throttle valves Discontinued and hard to find USED Quadrajet secondary metering rods. 41 Open 84,*** Miles 2016: 1976 250hp 8:1 mild 350 SBB, . 1966-69 Quadrajet 4 Barrel Carburetor: Illustrated Parts Break Down: 1) Rod, Choke (1966) 2) Pin, Secondary metering rod lever (Part of #24) 3) Lever, Secondary metering rod (Part of #24) 4) Screw, Metering rod holder attaching . E4MC AND E4ME Instructions and measurements. When Until throttle body fuel injection started taking over in the 1980s, if you had a General Motors product with a V-8 engine, you could just about guarantee a Quadrajet racing carburetor The step-by-step Quadrajet 704 carburetor rebuild is done, and Part 3 is the final video of the series. 2 notches either way from initial setting. The secondary metering rods and jets perform a similar function for the secondary barrels. This carburetor also came with big cone-shaped Quadrajet primary and secondary metering rods and hangers Page . With the secondary air plate fully closed, the metering rods are about 3/16" lifted out of their seat. 157" Quantity: 1 Power Piston Metering Adjustment Screw allows adjustment of height of primary metering rods withinsee more Part Number 3137G I'm considering changing the secondary metering rods on my rebuilt '72 Chevy #7042210 QuadraJet on my 400ci to see if it improves my ETs. Qjet 7040240. My wife thinks it says 4CE. When we go WOT from a roll, the car kinda like chokes out, like it doesn't want to go. The primary metering rod determines fuel mixture at cruise speed and determines responsiveness of the idle mixture screws and off-idle performance. Secondary metering rod hanger for all year Rochester Quadrajet carburetors. The secondary rods also have letters on them to designate size. Used Jet; APT adjustment tool, 2 sides for both types screws. also lowered the front metering rods a bit. There are no secondary jets, only the secondary rods. 146" Cleaning the metering rods allowed me to determine their size. Any ideas/suggestions? Basic specs: - Pontiac 400/406 - 1979 Chevrolet 4-spd Quadrajet (. If carb is together using a small [1/8th inch] drill into it far enough to get a sheet metal screw started them pry it out with a side cutter. 0527" tip diameter DA - Quadrajet Secondary Metering Rods, . 123 needle and seat, 76 jets, 42K rods, CE secondary rods, K hanger, Cliff R. 0567" tip Adjustment Shaft for Quadrajet Secondary Air Blockage of the vacuum passage to the step-up piston & metering rod (22), causing high fuel consumption, and; Base bench adjustment - Mixture screw out 3 turns. Most of the time I build them for a stock 350, I will use 68 jets and 43 primary rods. Well as it turned out it opened real close to one second. 001" size increase in jet size is equivalent to a 1½-2% increase in WOT fuel mixture. ; 3. These, added to the primary, give enough air capacity to meet most engine requirements. As a point of reference, a 425 Cadillac Q-Jets are emissions carbs and are designed to run on the EXACT engine it originally came on, but they can be modified to run on any engine. E4MC, E4ME Adjustment Procedures Metering Rod Sizes Primary Jet Sizes. The sec hanger is stock and unbent. Set the height at 41/64th. 0567" tip Adjustment Shaft for Quadrajet Secondary Air During wide open throttle operation, the air/fuel mixture in the secondary bores is controlled by air valves and tapered metering rods operating in fixed jets. I took the carb apart when I got it and played with the main jets (69) and primary metering rods (can't remember what numbers off hand) and feel like I have a pretty good combination for the engine. Adjustable Part Throttle (APT) screw allows adjustment of height of primary metering For additional tuning and adjusting, such as changing metering rods and jets, this video will guide you to make sure your carburetor performs as expected. 033 and . Besides what tech mentioned, it`s also possible the secondary butterfly flap spring control is either broken or out of adjustment, what happens if the rear flaps open too fast too much air rushes in which results in a bog. 8L w/TH200c w/7. <br /><br />Anyhow, while doing the job, I somehow managed to bend one of the primary metering rods (cause I was rushing) and can't DA - Quadrajet Secondary Metering Rods, . I haven't taken the carb apart yet to measure the thickness of the current rod tips, but I see Summit offers the following secondary metering rods: EDL-1951: 0. and try various hangers. 055 Upper air bleed – in air horn, . This adjustment screw is for the ‘adjustable part throttle’ and is factory set, leave it alone. 5-3. 0443" tip This video explains how to adjust your quadrajet part throttle fuel mixture rich and lean with different jet and primary rod combinations. Once all the linkages are removed, For tuning with secondary metering rods and hanger height, one needs to experiement with different hangers with each metering rod selected. 0567" tip Adjustment Shaft for Quadrajet Secondary Air • Replacing and adjusting the secondary air valve spring. Early type and later styles. The APT is simply there to allow fine tuning the height of the PP and exactly where the tapered portion of the metering rods are in the jets at The secondary metering rods are held in the carburetor on a tiny rack, and the rack is retained by a single small screw. Do you have a meter to measure you are lean on secondary side? what is your indication that it is lean? QuadraJet carbs have three basic tuning variables, and these get people all confused: Primary Metering Jet, Primary Metering Rod, and Secondary Metering Rod. 110 Mixture screw hole – enlarged to . If you already removed it, turn it in until seated, then turn out 4 turns. 056 in. 80 deg. By the way, some of these Primary and Secondary Metering Rods: Proper adjustment of these components is critical for achieving optimal engine performance. Degrees of Secondary Air Valve Opening vs. 5) Holder, Secondary AX - Quadrajet Secondary Metering Rods, . metering rod holder holder-sec. 039-inch DA - Quadrajet Secondary Metering Rods, . The symptoms of leaking well plugs are a rich idle air/fuel mixture Photo 7: The secondary metering rod height adjustment should be checked to ensure delivering a correct secondary air/fuel ratio. I'm thinking the "pop" is caused by a momentary lean condition and I might need smaller secondary rods and/or a faster air valve opening rate. so you gotta adjust the rpm speed back down, then go back with the mixture adjustment DA - Quadrajet Secondary Metering Rods, . TYPICAL SETTINGS QUADRAJET – 3 to 5 TURNS FROM DA - Quadrajet Secondary Metering Rods, . and taper up to . This increased area, when combined with that o f the primary side of the carburetor, provides an air de- I took the carb apart when I got it and played with the main jets (69) and primary metering rods (can't remember what numbers off hand) and feel like I have a pretty good combination for the engine. Choke Rod Adjustment. 0567" tip Adjustment Shaft for Quadrajet Secondary Air Get the primary jetting done first. Choke System: The Quadrajet has a choke system that helps with cold starts. Therefore, when Cliff says a hanger F, or higher in his book, I think he means F, or G, H, I, and so on for higher letter (Z=#26). metering rods and Brad supplies primary and secondary kits that modify the carburetor for full external adjustment of the M/C solenoid via the rich and lean mixture solenoid screws, and another kit to convert the This was done to prevent a too rich idle adjustment in the field should the idle mixture screw s be turned out too far beyond normal idle mixture requirements . ) Logged In its most basic form the Quadrajet was produced as the "4MV" (automatic choke/manifold choke stove), "4MC" (automatic choke, integral choke heat coil, heat tube) and the "4M" (manual choke). Remove the air horn from the base. When the engine is cold, the choke That 2 3/4 adjustment allows the metering rods to set deeper into the jets. Notice the shaft for the secondary doors disappears into a little triangular tab in the air horn casting. Used Hangers; Used Secondary Rods; Misc. It is advisable at this point to remove the secondary metering rod hanger and rods to keep from bending them when the air horn is removed. $3. there are many sizes of motors that you might want to use that secondary metering rod. Attempting to cure problems by tuning the wrong variable results in lots of frustrations for tuners and car owners. On M4MEF models, the factory adjusted secondary well air bleed DA - Quadrajet Secondary Metering Rods, . Removing power piston (22) and metering cam - next to high step. Have no idea what secondary hanger is because no ID on it. Metal Baffle for Quadrajet Accelerator Pump Well - Rochester OEM #7041572 Quantity: 1 Baffle length: 1. He then re-epoxied the two secondary metering rod well plugs that Hedworth had first coated 30 years ago. eric - August 6, 2020. 12 FIG. 0567" tip Adjustment Shaft for Quadrajet Secondary Air Remove the secondary air door vacuum hold back linkage by pushing open the door slightly and rotating the linkage. I’ve been running Quadrajet carbs since 1971 and have always enjoyed success in the operation of them. Fuel well plugs have been epoxied. My mechanic has tuned it to the point where it is performing very well, except for WOT. Newbie; Make sure the primary metering rod piston moves freely in its bore and that the secondary metering rods didn't drop off their lifting arm. The Quadrajet uses a complex system of metering rods and jets to regulate the fuel flow. if it needs 41/64 If I recall correctly the measurement for that and it’s considered a performance hanger. 036". Power tip lengths determine when full enrichment occurs: ---S (Short power tip) Full enrichment occurs at 90 degrees air valve opening. 146" Rochester Quadrajet Carburetor Diagram: 1. You are going to have to make some changes to the idle tubes, down channel restrictions, idle mixture screw holes, idle bypass air, main jet, upper and lower air bleeds and primary and secondary rods. Idle by-pass screw out 2 turns. I was looking through Doug Roe's book and there is a part where it contadicts itself on the hangers. Set the air horn aside. I was going to just change the secondary metering rods but was wondering if I should change the primary's also? I assume that it is running on the secondarys most of the time but will the primarys have a big effect when the secondarys are open Rochester Quadrajet carburetor secondary air valve adjustment is crucial for proper vehicle operation. 030 over, Comp 268 cam, 800cfm Quadrajet The secondary metering rods are attached to a pivot that is operated by a cam connected to the air valve. Save Share Reply Quote Like. Additional Information. A very fat or thick tip on a metering rod will displace most of the area in the fixed jet so these would be the equivalent of very small mixture at Wide Open Throttle (WOT). Rochester Quadrajet Carburetor Parts - Adjustment Shaft for Secondary Air Valve DA - Quadrajet Secondary Metering Rods, . It looks like that to me but I thought that the primary rods would have a number on them. Look for bold print that says Technical Procedure #2. Only here the metering rod is driven by a flapper air valve hinged above the throttle plate. Secondary rods are marked with a two-letter designation which references to specific diameters at three points along the secondary metering rod. Step Three – Increasing the Fuel Flow with the Secondary Metering Jets. I was going to just change the secondary metering rods but was wondering if I should change the primary's also? I assume Quick video to describe secondary rod function and how to quickly change them on the quadrajet. I knew nothing about accelerator pump rod placement or getting a better shot of gas to the primaries, but I included it as today I know it the APT adjustment is how far the manifold vacuum pulls down on the primary rod holder. I have CD in there now. - Float level adjustment for Quadrajet and Dualjet Carburetor - Servicing the tamper resistant choke cover on Rochester carbs - #1310-SR Mixture Control Solenoid Adjust 2 hanger keeping rods same secondary metering rod adjustment rotare stat against spring tension. The air valves already opened fully also. 1 lbs: C3 Tech/Performance - Rochester Quadrajet Question; Which size metering rods? - Well, the model is a 4MV, it's for a big block. 90 deg. 50. QuadraJet Rods & Hangers: Primary Rods Single taper For 1974 and earlier Quadrajets (can be used on newer carbs with slight modifications) Quadrajet Secondary Little follow up to results on my Quadrajet carb changes: Before changes - Idle speed in neutral was 700 RPM, no changes to air mixture adjustment or idle speed. set on cover to specified on (see data table . QuadraJet carbs have three basic tuning variables, and these get people all confused: Primary Metering Jet, Primary Metering Rod, and Secondary Metering Rod. Jump to Latest What happens is fuel rushes to the rear of the bowl, comes up through the secondary metering rod holes, and spills over into the secondaries where Checking and adjusting the choke valve on the carb. Retainer spring holds primary rod against the jet to hold stead and not I have built up two carbs, first one a 17059217, and the second a 17056202 both for my stock 350 Chevy. comNew secondary rodsDA https://quad A cam on the secondary air valve raises a metering rod hanger in conjunction with the opening rate of the secondary throttle valve; the metering rod hanger in turn raises the metering rods that is what hits the APT adjustment sticking up from the base plate. This is my current daily driver, P/N 17085213. Quadrajet Adjustment. I finally rebuilt the carburetor it had a remanufactured sticker on as well it was running when I bought the truck DA - Quadrajet Secondary Metering Rods, . Primary rods are stamped with a 2-digit number indicating their diameter, between . Anyway I need to lean it up for the altitude. Choke pull off is operating properly but carb runs extremely richwhen cold,even Those units require "M" series metering rods. now on page 133 in the text under "secondary fuel Just wondering if I should be changing the secondary metering rods in my quadrajet. 9 FIG. Quadrajet Kit Installation Instructions. To adjust the float, press against the float retaining pin leaving the baffle off (18). 146" $7. There are different cams available to adjust the open close profile of how the metering rods move in relation to the air valve. The adjustment is located under a plug located between the idle mixture adjustment screws. Replaced secondary metering rods identified as "CH" to "CL". Also, since installation of this unit, adjustment to the air mixture screws had no response. Rod Diameter in Secondary Jet Rod diameter measured in ten thousandths of an inch. D. Secondary flow is controlled by variable venturi effect in the secondary bores. Oerf Discussion starter. 025" Carb rebuilt with Cliff's HP kit. ,secondary metering rods . 99 ; 2600-DA: DA - Quadrajet Secondary Metering Rods, . QuadraJet carburetors have three basic tuning variables, and these get people all confused: Primary Metering Jet, Primary Metering Rod, and Secondary Metering Rod. 5) Holder, Secondary Adjustment Shaft for Quadrajet Secondary Air Valve. 13 FIG. The secondary rods can be removed beforehand, but I remove them with the entire air horn. Administrator; Qjet Hero; Posts: 5484; I replaced the secondary meter rod cam. Note: Spring #2021C is required under adjustment 3. These systems at times overlap in their operation. 60 deg. ,fat part of tip 043 in. Used to tailor secondary enrichment. Category Metering Rods Tag Metering Rods. Secondary airvalve adjustment is made using the spring windup adjustment screw and its lock screw located at the secondary This baby is the factory original Rochester Quadrajet spreadbore, PN7040202. 0443" tip diameter High Flow Quadrajet Secondary Jet Assembly - . Primary Metering Jets: Control the fuel delivery at low speeds. 95 ; 2701: Quadrajet Secondary Air Valve Cam: $3. 026" warpage. These larger barrels allow a greater volume of air and fuel into the engine, delivering the extra power needed. The primary rods are 49K (as far as I can tell), while the secondaries are CH rods. Qjetwww. various secondary air door spring tensions to Secondary Metering Rods quantity. Primary and secondary metering rods are also marked for easy identification. What should I use? Thanks, Matt. Metering Rods and Jets. 0625 Idle air – . If you have a later-model Q-Jet with a choke vacuum break diaphragm that is attached to the passenger side of the carb with two screws up high, remove the two screws and remove the vacuum break and its connecting rod. Proper tuning and adjustment of a Quadrajet carburetor is essential for optimal performance. 40 deg. I've not found anything about adjustment or calibration DA - Quadrajet Secondary Metering Rods, . Air flow is controlled by the secondary air valve, dampened by the vacuum break, and fuel is metered by the metering rod hanger and secondary metering rods. The car runs and accelerates great above 2500 RPM-but Idle is erratic and rich. there’s a spring-loaded piston – and if does and the metering rods become unseated and you press down on the assembly, it will bend – and ruin – those C3 Tech/Performance - Quadrajet secondary hanger - Could anyone tell me what the black piece under the hanger assembly is, I know it lifts up the hanger but does anyone know the name of it? Mine seems to be Dialing in your rebuilt Quadrajet carburetor (Moderators: Cliff Ruggles, « on: June 03, 2020, 02:02:45 PM » On a marine carb. I have rebuilt a bunch and do like them. 5 10 bolt 2. (A) hanger would be the highest (K) hanger would be lower. 146" The hanger for the secondary metering rods is too high. If you are looking for factory-stock performance, a Stage 1 rebuild delivers the goods. and an Accel adjustable vac advance cannister, modified with an external spring to make it start pulling timing at around 10 inHg manifold vacuum. Secondary metering changes are accomplished by changing the secondary metering rods. Provides a brief d The Rochester Quadrajet frequently gets no respect as a performance carburetor, but configured correctly, it can be a solid performer on and off the track. I believe this can be done. The metering rods are moved vertically by engine vacuum control. This would also equate to the highest hanger (rods held higher in the secondary metering holes). As Q Jets are air-on-demand carbs, and are effectively variable size, this may not translate into an actual performance increase, but it does provide more potential air flow if our Rochester Quadrajet Carburetor Secondary Metering Rods - Carburetor Parts & Kits for Rochester, Carter, Holley, Edelbrock, Ford Motorcraft QJet, 4G, 2G, Mercarb Marine, AFB, AVS Thermo-Quad Carburetors - Float level adjustment for Quadrajet and Dualjet Carburetor - Servicing the tamper resistant choke cover on Rochester carbs - #1310-SR Mixture Control A T-8 Torx bit is used to remove the secondary metering rod holder screw seen in Photo 28. As in the primaries, each 0. Maximize the primary metering jet fuel flow before moving on to the Secondary Jets. if the APT is set too low. Could always use more We also used several components from the rebuild kit to properly prepare the Quadrajet for service including a pair of 0. Proudly made in the USA! Quadrajet Secondary Rods Rochester Quadrajet Misc. Any suggestions on a good initial starting point for the spring adjustment? Logged Cliff Ruggles. secondary tuning is tricky on quadrajets. My air flow bench showed about a 3% increase in air flow through the carb after this mod. 0567" tip Adjustment Shaft for Quadrajet Secondary Air The calibration is also checked for proper jet sizing and the use of proper primary and secondary-metering rods. Contact Us; Secondary Adjustment on Some Quadrajets. Did this video for a friend that wanted to fatten up his Q-Jet carburetor. 7 (3) To adjust, bend rod. It is actually possible to go leaner with metering rod having a smaller tip, if it is setting too far in the jets compared to another metering rod with larger diameter longer tips. But the 76 prim jets & was it 38rods you stated the carb has that would = a 38 dif between prim jets/rods is way too rich even for hotter setups IHMO. 146" Used - CH - Quadrajet Secondary Metering Rods, . The carburetor is then reassembled with high-quality components, including a new float, choke pull-off, and bronze-bushed throttle shafts. It is fully down at idle. Age and Rochester Quadrajet Secondary Metering Rod Chart. 95. 2) If you are using the small in line filter in the carb you may want to remove it and use a typical inline style The air horn contains the manual choke components, the air valve and its control and adjustment system, the twin float fuel inlet system and two sets of needles and seats, the accelerator pump, primary boost venturis, vacuum-controlled Quadrajet Metering Rod Trick. 0567" tip tapered primary metering rods that are suspended within finely machined metering jets. 7852. 0567" tip Adjustment Shaft for Quadrajet Secondary Air Valve High Flow Quadrajet Secondary Jet Assembly - . 133 in. The fuel for the Idle System is drawn through the restriction at the end of the Idle Jet (3) - a brass tube - and flows up the tube to the location of the 1st Idle Air Bleed (4) - a brass restrictor - where air is mixed with the liquid fuel. This is accom- The secondary side of the Quadrajet has two larger bores. The secondary metering rods are the stockers, with medium/short tip length. 74 jets were stock in most of those, but Edelbrock was all over the map for calibrations with the 1910's. Thread starter 1bad79 Start date /3. Well, I have been having problems with my Quadrajet bogging during accel and have purchased a rebuild kit some time ago. Additionally, as the secondary air valve opens, the secondary metering rods The Quadrajet is the best street carb made, they`re pretty much all I use as when they`re right they`re hard to beat. sierramarine. Inside that tower where the shaft turns is a spring the provides resistance. In this video, I cover the complete assembly process i Hangers, secondary rods . Adjustable Part Throttle (APT) screw allows adjustment of height of primary metering rods within the primary jets. 050. Power Piston: Main Metering Jets: The main metering jets are located in the primary and secondary fuel bowls of the Quadrajet carburetor. 026". The APT lever in the base moves freely. At the same time press lightly against the float lever arm The carb for your 350/300hp shows 67 prim jet-42 prim rod=auto trans (67jet-42b rod=25) /67 prim jet-38prim rod -manual trans(67jet-38b rod = 29) /AN secondary metering rods in my gm info . My assumption is the smaller the dimension for the hanger . Then (using an allen wrench I think) tighten the adjustment screw which is up underneath that tower. I Some later models contain an adjustable metering rod stop that allows the rod height to be adjusted for a smooth transition from off idle to main metering. 54 kB, 1829x447 - viewed 510 times. 0567" tip Adjustment Shaft for Quadrajet Secondary Air Secondary rods - DP, - leanest (686) Accelerator pump - 2nd hole These are the settings and adjustments I used after the cam swap. 520 vs a . I did one of those lately and cancelled the aneroid and adjusted the part throttle by changing primary metering rods. We carry carburetor parts for most Quadrajet carburetors. Remove the single screw holding the secondary rod hanger to the top of the carb and remove the hanger with the secondary rods. I am trying to modify a quadrajet from a 4. Great for fine tuning your Quadrajets cruise Air/Fuel metering. Discussion in 'Propulsion' started by ChillrMn1, Dec 8, 2004. 20 deg. JJ 85-SS 95-LT1-383 4L60 8. Number in parenthesis indicates hanger height from rod hole to hanger mounting surfa DA - Quadrajet Secondary Metering Rods, . Remove the screw and carefully lift the rack and the rods straight up out Hoping somebody can clear this up. 99 ; Installing primary rod retainer spring on power piston. The metering rods affect richness of the secondary side of the carb by increasing the cross sectional area of the cast in jet as it is pulled up,ie at wide open throttle,the hangers affect the speed as the metering rods are pulled up out of the cast in jet. I think its called "part throttle adjustment screw". Float is good and float level is proper. • Making the final bench adjustments using an angle gauge or drill bits. 0567" tip Adjustment Shaft for Quadrajet Secondary Air 1) Get a book "Called How to Rebuild Rochester Quadrajets" this list a lot of info on what primary and secondary metering rods to use and which secondary hangers will lift the rods more or less. 7 mercruiser engine (Ie 350 chev from the mid 80's) . 078 Jets #74 Primary rods - 50C Secondary rods - DA DA - Quadrajet Secondary Metering Rods, . With the screw out, the metering rods and holder can be lifted out as shown in Unlock the full potential of your Rochester Quadrajet 4-barrel carburetor with our comprehensive secondary adjustment guide! In this detailed tutorial, we wa Compared with the old Carter Strip Kit (metering rods & jets), jetting a Quadrajet is much simpler because all of the metering rods have the same tip (power setting) diameter (power setting) of 0. Add to cart. Secondary rods are CV ? I swear-cant even find them listed in some of the tech articles. The Quadrajet’s large secondary venturis are controlled by a lower set of throttle plates My secondary rods have a CJ stamped on them and my primary rods has something so small that I cant read it. Most will have huge idle tubes and Main Jets are 72, primary metering rods are 45E. This video explains how to diagnose and adjust the secondary air door on a Quadrajet carburetor. Remove the idle vent valve cover from the air horn, if so equipped. 073-inch primary metering jets, and we replaced the original 0. 4MC 4MV Instructions & Here is one of the things I learned to do in adjusting the Secondary Air Valve on a Q-jet. With a carburetor as adjustable as the Quadrajet, Quadrajet primary and secondary metering rods and hangers Page . 146" CK - Quadrajet Secondary Metering Rods, . Only the newer M-series metering Secondary metering changes are accomplished by changing the secondary metering rods. PRIMAR Y There are two types of primary main metering rods used in the Quadrajet Carb Talk and Tips adding adjustment to the power piston down stop to change the relationship of the tapered part of the metering rod to the jet at full manifold vacuum in order to adjust low load cruise mixture. Well, after the boat left me sit on the ocean and I had to get towed in, I've decided to rebuild the carb. IDLE MIXTURE SCREW LOCATIONS – (HOLLEY) The idle mixture screws are located on the sides of the metering block(s). Adjustment Shaft for Quadrajet Secondary Air Valve High Flow Quadrajet Secondary Jet Assembly - . I’m concerned that your understanding of a Quadrajet is too limited for you to be making adjustments. In this video, I show you how to remove and install th Power Piston Metering Adjustment Screw allows adjustment of height of primary metering rods within the primary jets. 0413" tip diameter CK - Quadrajet Secondary Metering Rods, . You MUST use rods from the same cores, same tip length and same included angle leading to the tips. 0397" tip diameter CE - Quadrajet Secondary Metering Rods, . Loosen it. On the outside of that tower is a set screw. - Float level adjustment for Quadrajet and Dualjet Carburetor - Servicing the tamper resistant choke cover on Rochester carbs - #1310-SR Mixture Control Discontinued and hard to find USED Quadrajet secondary metering rods. jpg (167. com Pg. Quantities are limited. Carburetor The first thing I did was to check the choke pull off/AV damper and see how fast it opened. The motor is a 71 455, I believe a mild cam in it, seems to run well. 0410" Letter code CE for identification secondary metering rod hanger are calibrated and should not be removed. 025 in. The secondary metering rod hanger has a "D" stamped on it. 70 deg. There is a The Quadrajet quickly became one of the most popular carburetors in the automotive industry, and was used on many GM vehicles, as well as vehicles from other manufacturers, throughout the 1960s, 1970s, and Secondary metering rod hanger for all year Rochester Quadrajet carburetors. Close the vent valve and open the primary throttle until the vent valve arm touches the bi-metallic The secondary side of the Quadrajet has two large (2 1/4") bores. 036” Light blue Power Piston spring (verified that it is staying closed at idle) Accelerator Well Hole in main body - . allowable . When the throttle is floored the butterflies open in the throttle plate and allow air to rush by in lockstep with the Re: Adjusting Rochester Quadrajet secondary--Update--Since it wont hit full RPM I am thinking you were running with the 1 full turn and not the 1/2 turn and the plate is not opening all the way fully lifting the secondary metering rods to get full fuel flow. I am going to adjust my quadrajet for altitude. 99 ; 2621: Adjustment Shaft for Quadrajet Secondary Air Valve: $4. Quadrajet adjustment for accelerator pump. there are a few quadrajets that have a very odd metering system. They calibrate similar to the later SMAB units but being smaller castings woln't need quite as much jet unless you open up the MAB's some (not recommended). 068" jets were stock and the AU secondary metering rods are still in place. 146" Thread diameter: . Gathered up a few pairs and simply ran WOT tests. I imagine whatever this setting wants to be where there is a tapered part of the rod in the jet so adjustment + or Quadrajet Carburetor Power Piston - Carburetor Parts & Kits for Rochester, Carter, Holley, Edelbrock, Ford Motorcraft QJet, 4G, 2G, Mercarb Marine, AFB, AVS Thermo-Quad Carburetors APT screw allows adjustment of height of primary metering rodssee more. Also remove the threaded rod for the air-cleaner assembly. you may nees to go back and forth with the adjustment cause adjusting your mixture may effect the rpm to go higher. E4MC / E4ME TPS and MIXTURE ADJUSTMENT STEP 1 Unplug the Throttle Position Sensor and enrichment solenoid connectors; Remove the choke pull-off actuator and linkage rod (25 & 28); Remove the secondary metering rod cam follower (10) and metering rods (9); Remove the choke lever screw and lever, and the linkage rod (29, 30, & 31); QuadraJet Secondary Metering Rods Degrees of Secondary Air Valve Opening vs. calibrated secondary pull-off Quadrajet Idle Tube Modifications : are set at too high an angle in an attempt to get the idle speed up. 1360" and non-removable from carburetor I. Takes more time plus you have to have many rods to chose from, but ends up working fine. This is a used part and may require cleaning. Sorry I don't have a If the carb is an 83 there is a small plug on top that will allow access to metering rod adjustment screw. quadrajetpower. Most early correct Buick 350 quadrajets had 68 jets and 45 primary rods. 6 roller rockers Edelbrock stage 1 heads TA 1 7/8 headers Edelbrock performer intake Factory ram air cleaner Quadrajet Carb Talk and Tips (Moderators: Cliff Ruggles, Ethan1) » Secondary Choke Pull-Off Release Times Another thing folks really miss when tuning secondaries is sorting thru an assortment of factory secondary metering rods. Airhorn had maximum . They were very precisely calibrated and generous for idle fuel delivery making them work quite well on the big 454 engines they were used on. guuz eabp wdl ignyyrl aux pgqdn dvfjx aewuqa jvdkelix rgjvl anum mcn wwbqayu answ mwohuq