Holley Carb: Proper Carburetor Jetting (CARB BASICS PART: 3)
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- Опубліковано 12 гру 2015
- Going through Holley Carburetor Jetting and How to Get it Right
link to 02 gauge - reading plugs with modern fuel is dead.
www.ebay.com/sch/i.html?_from=... - Авто та транспорт
That's deep! Thanks alot man! I'm 100x more confident about this job now.
Thanks for the information. It's great to hear from the more experienced gear heads. I'm getting back into drag racing since I quit in the late 70s. It's funny how things have changed with efi. Just give me that Holley carb man!
thanks for the tips and guidance. .definitely helps my overall understanding ...once again greatly appreciated.
The most informative video about jetting ever! Thanks for the info!
Thanks for the video! Now I have a better understanding why my engine likes 76/84 jets instead of 72/80(Stock). High rise DP intake and a 1" open spacer.
if i remember right on a holly carb the jet numbers are 2 % for each jet number. a friend had 1960 Buick. with Rochester 4 bll. he went to pikes peek . it all most didnt get to the top. i built him an AFB. the next time he went there he says it just as good at the top as at the bottom. years ago i did a LOT of work on AFBs. if you cant tell i like them.
You know why your videos are so good? It' not necessarily the content, but the way you deliver it. You don't spend a lot of time going, "Uh....so....uh....and then.....uh....you...............uh". Good stuff. I keep finding myself back on your videos.
I do wish i spoke better, i have improved over time. as an engineer, it definitely is not my strongest suite. i just hope that people are getting the info that they need!
Hollywood, you obviously didn't read my post. Open up your eyeballs, you doofus.
@@ThunderHead289 I came back to this video randomly and saw my face in the comment section. lol I've been farting around with the jetting on my holley dp. Taking my 66 F100 on a 1,500 mile trip this Saturday. ACK!
it does, thanks very much for the info. I will try that also and hopefully get this thing to run perfect. I'm not too far of the mark...
Thanks for the info got a holley 570 for my 4.8ls running very rich feel more confident about changing the jet after watching your carb videos
I've got a stock 289 A code with modified J code heads, 1.94 1.60 Ferrea valves, ISKY Mega 280 cam nets about .551 at the seat with 1.6 ratio roller tips. Using Try Y pipe that are wrapped with DEI Lava wrap, was having carb heat soak issues from the pipes, the wrap pretty much resolved under hood temps issues. Using Cobra high rise intake that is port matched, and blocked crossover, with open wood 1/2" carb spacer. Built up the carb using 3310-1 bowls, and throttle plate, 600 CFM 4150 main body that has been worked over machined to fit the larger 3310 base plate, smoothed out, choke horn is gone. Primary jets are Comp Jets 69.75 and 78 secondary with adjustable secondary vacuum pod 5.5 power valve it's a little fat but it runs really good 65-70' air temps I get about 11" vacuum at idle. Still little more work here, think it needs a good spark curve, I'm looking at the MSD E curve, and a good dual A/F ratio gauge.
you are really in deep to this!
allow me to potentially add to your list -
what type of fuel pump are you using? do you have a return line set up?
Really good videos body thanks.i just wondering I have 79 f150 whit a 460 engine I’m going to install a new 670 avenger is this going be ok or what you think.
I have a 77 Bronco that I am going to put a roller motor in and was going to go carbureted do to the simplicity. You stated that when you travelled through WV you had to re jet your carb a few times. Well, that's where I live and my day may start at 700' go as high as 4200' and return in the same day or half day. Seems kind of like a nuisance to stop and re jet constantly especially when you may change elevation of 2000' or more in less than 10 miles. Suggestions? Or would it behoove one to go with a Holley Sniper system? Thanks
Could you share your opinion on jet size. Holley 600 cfm 4160 vacuum secondary. Has listed jet size of 122-642. 1973 Pontiac 400. 700 ft above sea level, comp cam the smallest they had for RV type Power. . Holley performer dual plain with open spacer to convert it from a spread bore. 1967 Bonneville Convertible ( heavy car) dual exhaust and stock mechanical fuel pump. Rebuilt the carb has #41 jets in it?
Great content. I would like to know if you can help me with what size jests I need for the elevation of 5,000? Thank you
Opinion? I also have a Holley 670 Street Avenger. Mine is on a 350 powered 65 impala. I bought the carb from Summit based on their advice after they factored in everything I was running. The car starts right away and runs decent but it seems the carb is running really rich based on the exhaust smell and it also stumbles when I floor it. I first thought my problem was timing but I haven't had any luck playing with that. If I decrease the fuel air mixture at the carb any more the car stalls as the meter adjustment is almost fully closed at that point. People who I've talked with on this suggest carbing down to a 600cfm and others have suggested just re-jetting my Holley to a set of smaller jets. My gut tells me to get a full dyno tune as I have a very tall cam. I just pulled my carb from the box and bolted it on. I only adjusted fuel and idle on the carb. Didn't touch the floats. I also am not currently using a fuel pressure regulator.
+RYTHMIC “RYTHMICRIOT” RIOT if you do carb down, go with the summit 600 - tremendous carb. if its bogging when you punch it and you have a tall cam, i almost guarantee its accelerator pump related. and lean! try idling at around 900 and setting your pump cam position accordingly. try this and get back with me.
NEED HELP WANT TO BUY A HOLLEY 600 for a 12a rotary but I think it needs jetted down to where if it was a 465CFM. What jets come in a 465CFM Holley?
this sound quality is far better!!!!!
I have black smoke sometimes . Do I need to jet down a bit?
Is there a specific O2 setup you would recommend for a 66 chevelle with a 427 big block? I am also running the 670 street avenger.
I have a chevy 305 small block and it has a 650 holley on it and im trying to figure out the best jets to run for best fuel economy does anyone know what will work?
Install an o2 gauge...saves time
I have a Quick fuel 600cfm that has bigger jets than the avenger I just bought. Both run rich to me. My question is if the avenger is really putting more fuel if the jets are smaller?
Look into air bleed jets, I had a quickfuel and damned if I couldn't get it jetted always so rich, ..... I found out later quick fuel had some real small air bleed jets causing a rich condition across the board just my 2c
Hi I have a holley 80309 with vacuum secondary I think I mixed up the jets in the secondary metering block when I took it a part there is a 80 and a 90 jet... so I would like to ask does it matter in which way they are positioned? If so where should each one go? Hope you or someome can help me.. Thanks in advance
just make sure the smaller jets are screwed into the primary side of the carb securely.
I am going to buy a fuel injection system in the future. I am planning on driving from Florida to Arizona and changing jets and metering rods often don't appeal to me. Is there a way around all this? Great video.
Its not as bad as it sounds if your just cruising through. Back when there was no EFI we drove our carburated cars all over without rejetting. I do remember it my car not running well when I was in the Rocky Mts though.
How do you keep fuel pressure steady?
I have a Holley carb question... I'm trying to save my mid 80's 1850 with a refresh after the car has been sitting for years. Question is how to remove the old gasket material? I'm no stranger to removing old gaskets from things and have worked on cars professionally. I have never seen gaskets so stuck on anything I have ever worked on. There has to be a chemical out there for this? Regular old locktite gasket remover doesn't even touch this. Even a razor blade doesn't do very well at all. It's like the gasket has turned into a rock. The carb body and other parts are too delicate to get crazy with a wire wheel.
Acetone and gloves. And a mask and a hot cup of tea 🍵
All you should have had to do is adjust the screws on the side of the metering block those meter the fuel not the air. And as far as changing Jets not everybody has access to a drag strip but if they do either a drag strip or a dyno that's how you really know what your motor wants..
Or just run a wideband. And the mix screws only directly adjust the idle fuel metering
Ever float has slightly different bouyancy. The need for adjustment is important
Does it hurt to run power valve block off plugs in both your primary & secondaries?? l just get tired of blowing my power valves & them having to replace them all the time, thank you for your time, excellent video👍👍
That's odd that you are blowing the power valves often. Drag racers and circle track folk will block off both power valves, but they also have to jet up for the difference. On a car that's driven on the road, your cruising fuel mixture would work out to be too rich. On a street car you want to retain the power valve - what carb in particular do you have?
ThunderHead289 / its a 1150 dominator on a 428 scj in a 67 galaxie xl, its a strip car but l do drive it on the street from time to time.
+GALAXIE 67 what led you to that large of a unit? What rear gears and tranny do ou have?
ThunderHead289 / its a C6 with a 3000 stall converter & a 9" with 4-11 the moter has been up grated to about a 525 with about 750hp it runs 12.2 which itsnt bad for a 4200lb car, lm still working on the waight problem?? not to bad, l started working on it in college for automotive, then it went in to storage for a long time, l just started on it again with in the last year & l forgot a lot about what l did, & after going through it lm starting to wonder why?? lll just go with yong & dumb
You need to get the anti blowout kit from holley, you drill a hole almost through your baseplate and install a little round valve (plug).
Have you ever fiddled around with aftermarket fuel blocks like the Percy Adjust-o-jet?
I have not, they are a neat idea but expensive. If have to be running an o2 to feel comfortable with one. I've moved away from holleys to the summit carbs that are a little different
It is interesting to hear good things about the summit carbs. In all my carb research and understanding very few people even mention the summit stuff. They usually mention on the top 2 and only the really expensive versions of both haha. Thanks for the series on carbs.
why do my idle enrichment screws not change anything all the way in no change i had devane carbs do some work on my carb that was suposed to lean out the bottom end he drilled some holes in the butterflies and opened something in the metering blocks and now when i stomp on the gas it pops boggs and runs like shit watcha think
+William Morton The idea behind drilling small holes in the butterflies is to give you a little more air to get the engine to idle without having to open the throttle blades so far and getting past the idle circuit. Often with a large cam by the time you get the blades open enough (enough airflow) to get it to idle you're past the idle circuit and into the cruise area or main circuit. with our hollies, we can open the secondary throttle blades a bit to account for this. this should have been done first before drilling. poping and bogging is a direct sign of a lean condition and that your now getting too much air.
- with the idle mix screws not doing anything, that only happens where the primary throttle blades have been opened to the transition circuit (rectangular slots).
- its hard to say without seeing it, but make sure first that your primary throttle blades are open to the right amount.
what was their reasoning behind doing what they did?
Good tips, but what you change to go leaner or richer? What part of the carb effects what throttle position or rpm?
Place respond we warriors need to know
hi i have a 305 with a 600 4160 holley. the prim jets were 66 so i changed to 62 . how do i find out if that is the right size for that motor im new at this thank you
Why are you at a 62 jet, would love to help you here
ThunderHead289 the 66 were too rich .
Run the car on the hiway, then pull the plugs. if they're sooty go down two jet size, if they're white looking go up two jet size. when they're tan color they're just right. That way you have the right jets for your location were you live.
just wondering, I need to step down on my jets... I have 66's in there now... fall is coming here in new england and my car is running very rich... any suggestions on what size I should go down to? 64? 62?
Usually you need bigger jets when it gets cold because the air is denser. How do you know that you are rich?
I've adjusted the carb as best as I can and you can smell fuel out the tailpipe still and rougher idle... When we had a cold spell down to the 50s the car ran smooth as silk. New carb also. I installed it about a month ago. Holley 600 on a 1964 Buick skylark 300 V8
I really think it's too much carb for the engine. But I figured I try the jets first. My friend suggested to me to go down to 64 from 66. Should run better now while it's still warm out during the day, and as for the winter months it should still be OK... He told me not to go too low only because if it's really lean I may run into major problems down the road
+Michael Holden jets play no factor into the idle, set your throttle blade so that only a square is showing on the transfer slots. Loosen your distributor hold down nut. Fire up the car and adjust the initial timing until you are idling at the desired rpm. Also, watch my video covering adjusting your mix screws with a vacuum gauge and do that also. It's all a balance, you will move the timing around a degree or two, adjust your mix screws a bit, and move the curb idle screw around a little (but only 1/4 of a turn either way from the transfer slot square on that one! ) does this make sense?
hey man. I have a Holley 650 on a stock 350 with long tube headers, I live by the Jersey shore so I'm at sea level, my carb has 582 jets on the primaries. does that sound safe? I don't have an Afr guage or even a bung in the exhaust for one. no spacers and a low rise intake, it's also spreadbore. carb is a 7002-1
I'd look into what that specific carb had factory, then get yourself a good 4 hole spacer and try it out. I Bet a stock jetting and the spacer would help things a ton. I wish I was around all the people who ask me questions, I'd just come right out and do all the tuning for them.
The car is an 85 firebird. With no spacer the air cleaner touches the hood. Spacer isn't really happening lol
+Chris Bentley that's pretty tight. I recently did a little 2 part video series of working over a subscribers carb. Check my recent uploads. It lays everything out in one vid
I will. Thank you for all of your input.
What are 582 primaries, never heard of numbers like that on a Holley.
if youre only supposed to have the fuel at one curtain point in the bowl, why do they even make it adjustable?
The floats? If you have a fuel pressure regulator, turn it up or down, you will see the float level change. You will need a lower float setting to hold the level where it should be with more fuel pressure. Sounds stupid, but for whatever reason that's how it is. Float level settings are greatly effected by fuel pressure.
yeah me too but those guys dont share info because if you know what they do you dont have to pay them i just wonder if mot having any adjustment in the idle enrichment screws is leaning me out up top that was Never an issue before i have the enrichment screws one turn out any more than that and the idle goes down and it smokes and goes way rich at idle wich cuses me to open up my curb idle screw wich takes up transfer slot yadda yadda yadda is it possible he didnt drill big enough holes will to lean of an enrichment screw setting lean out the top end? wtf
+William Morton though it is true that each curcuit builds off of each other and hence why i have an order to the way im making these videos, it should not have that much effect to the point that you get lean popping. one turn? mine are always 2 1/4 to 2 3/4 on everything. all that aside, that isnt your top end problem. make sure they didnt fool with your float level, if its low it will adversly effect top end jet performance. did they tell you everything they did or did they just mess with your carb then give it back?
MAN, I haven't seen that big of a sentence in a long time.
Great video thanks yep I agree I have a circle track carb on my 69 250 they all say it was designed for that truck or big trucks in general they all ditch the 50 cc accelerator pump and use a 30 cc I called a well know carb seller builder for circle track he told me if I do that mod I will have a major stumble off idle and basically I just asked so there's no mods I can do to keep the performance but save a little fuel he basically said no ?????? Do why do they all drill the throttle plate holes out ,take off the choke plate , use a 30cc pump and all that ? Maybe he was running me around in circles ....
Have not heard from you in a while
Check my channel, I've posted a couple one being particularly interesting recently
how do you no what is the correct air to fuel ratio,like what is normal readout ?
cruising should be around be around 13 to 14 - i never go above 14 because of runner length issues. under power you should shoot for 12 to 12.5 - i usually have an o2 on board
+ThunderHead289
do you have a video of the o2 setup, how to plug it on?
i dont, hilarious really that i have never made a video on it. you have to weld in a fitting to your exhaust. its basically like an o2 sensor with a readout.
How to adjust the float on a non adjustable float Holley carburetor part number 80457-7
You would have to bend the tang connecting the float to the needle and seat. I wouldn't mess with it though if you do not have a sight plug.
ThunderHead289 Do you have any pictures of the float. that can give me a l deal how to set the float. none adjustable float Holley carburetor
Will Jets size will make your headers glow red?
Late timing will do that
@@ThunderHead289 I had like 3 people look at it and they can’t figure it out I recently put a new holly carburetor and after like 3 min of the truck been on idle engine bay gets so hot and headers start to blow red. I have a 383 stroker some one told me I might need bigger Jets.
What cause carb popping on acceleration
To much air not enough fuel = lean miss fire. Check make sure no vacuum leaks. Accelerator pump giving a good squirt of gas.
the 66 jets were too rich
my fuel pressure gauge jumps around all the time....is that a bad fuel pump?
Danny Borelli jumps around from say 1 to 5 or just bounces between 4-5? Is it a liquid filled gauge?
Vaporlock I have the same issue...run a return line.
yes,liquid filled, jumps from like 2 to 5...
Danny Borelli the mechanical pumps will do that to a degree. If you are having issues with how it runs, I do also recommend a return line with return style regulatory
my fuel pump does have a return line
hell i dont know the guy is suposed to be the shit did the carbs for farm truck and daddy daves somoma and shit so if the primary throttle blades are passed the slot at all the idle enrichment screws wont work they never worked ever even before he drilled the butterflies i have no clue man i started out with a pig rich idle conditon on a car that ran pretty damn good to a carb that idles alot better and lower rpms locked in at 34degrees but now runs like ass it frustrating
+William Morton gotcha, first thing i always do with tuning any serious car is hook in an afr gauge so i know where im at. it just sounds lean up top which wouldnt have to do with the butterflies. so quite possibly that is all set up right. wish i knew what he drilled in the metering block.
Had to stop in the West Virginia mountains to rejet your carburetor .. sounds like you need to buy an Edelbrock 800 CFM
+Kenny S that statement makes zero sense son
Not to mention edelbrock carbs are garbage
he said i know exactly whats wrong with your carb these quickfuels all do the same thing he took off the metering plate stuck a drill bit inone of the holes and said .035 ok come seeme tomorrow after work and it will be done i came back the next day there was holes in the butterflies and he said put it on your car turn the idle enrichment screws in until it starts to stumble then back them off till it smooths out plus 1/4 turn when i got it jome and put it on it barely wanted yo run wouldnt hardly hold 500rpm and the idle enrichment screws yeilded no change called him up told him what was happening and he said turn up the curb idle screw no more than half a turn a little over a quarter turn yielded 800 rpm so i took it for a ride idle enrichment screws at about 1 1/4 turn good down low garbage anything passed 3500 got worse when i turned the enrichment screw in more but 1 1/4 was still too rich at idle black smoke bad fumes 2 turns om afraid would drown the thing i went 1 3/4 turns and the idle went down wich required more curb idle and the cycle starts all over
+William Morton what type of fuel pressure are you running? do you know? thing is way rich, usually a big cam takes more idle mix because the reversion requires a richer mixture. try opening the secondaries a bit first to get a bit more air in. that idle just isnt right at all.
your timing is going to hurt your idle if your shooting for anything less than 1200. im sure youd be around 19-22 idle with 32-34 total, with an aggressive advance curve. i just have never been successful with locked timing myself.
if it were my car, not having personal physical knowledge on your car, id set it up first with a carb spacer and a regulated fuel pressure at a consistent 6.5 to 7.5. have my primary throttle blades set to just where the square is showing, idle mix screws 2.5 turns out. timing set to at least 18 degrees with total at 34 (all mechanical). stock sized jets in the carb. id then light it off. thing should hold an idle there and you can tune accordingly. what size engine do you have and what sized carb?
when i was 16 i had a quick fuel carb and i paid someone 50 bucks from a speed shop to help me tune it. they didnt tell me what they did and it never ran worse. from then on i decided id learn this shit.
Confusion here. "Jet up" and/or "Jet down"....no definition for either. "Jet higher" ..... "Jet lower" .... neither defined. No examples given do that a person could try to guess what you mean.
Move on to the next youtube video to figure out what is going on.
Who has ever heard of stopping a family car driving through some mountains and disassembling the carburetor to make it through.
Your credibility is just ruined.
I really dislike "experts" like this.
I say exactly what to jet up and jet down for, and if you go up 5000 feet in elevation, your going to need to rejet. This isn’t rocket science. Snow mobile guys make these changes religiously.
I really dislike ignorant people who are incapable of learning or wrapping their head around the shear quantity of info that they don’t know.
See, two can play at this game.
ThunderHead289 this is what happens when someone understands what your teaching ua-cam.com/video/4qHP14Uxt8o/v-deo.html , thanks for taking the time to make these videos