they are in the main body, above the venturi, just near the accel pump shooter.
maybe this pic can lighten up my words
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| Tuning a holley https://www.slantsix.org/forum/viewtopic.php?t=12749 |
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| Author: | slantyslanterstien [ Sun Apr 24, 2005 3:26 pm ] |
| Post subject: | Tuning a holley |
I need some help with my truck, it runs terrible and has a big flat spot in the power band, I am running a holley 350 cfm 2 barrel with number 50 jets and a 6.5 power valve, clifford headers and water heated intake manifold, 2.25 daul exeust with free flow mufflers, Ignitor ignition, new wires, coil and spark plugs. It is stock internal,no cam. I can't get it to run right I've tried differt jets and power valves but it backfires and runs bad. its not to bad if you accelerate slow. please help. |
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| Author: | Charrlie_S [ Sun Apr 24, 2005 5:30 pm ] |
| Post subject: | |
What year is the truck, auto or standard shift? Is the backfire, out the exhaust or intake. Just a couple of guesses, adj the valves. Try changing the accelerator pump cam/shooters, if the backfire is in the intake. Need a little more info. |
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| Author: | Dennis Weaver [ Sun Apr 24, 2005 5:37 pm ] |
| Post subject: | |
...and if it bacfires out the exhaust, it's probably that holley running rich and intermittently fouling the plugs (putting out the spark) and then igniting the mixture in the exhaust port/manifold. D/W |
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| Author: | slantyslanterstien [ Sun Apr 24, 2005 6:52 pm ] |
| Post subject: | |
it backfires mostly through the exuast but sometimes through carb after you rev it up. i am sorry if i didn't provide enough info, i am new at this. it is a 81 Dodge pickup with a maunel 4 speed. what do you me by ''valves'' and ''cam/shooters''. we can get it tuned to idle nice. and when going down the road it seems to run worse in 3rd gear than the other gears. |
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| Author: | slantyslanterstien [ Tue Apr 26, 2005 6:52 pm ] |
| Post subject: | |
I pulled a spark plug out and the holley is defilently running to rich, should try smaller jets ? |
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| Author: | argentina-slantsixer [ Tue Apr 26, 2005 9:50 pm ] |
| Post subject: | |
Nope, you need to A) reduce the idle air jet and B) enlarge the main circuit air jet. those are two little holes on top of each barrel on the fuel bowl/metering block side. The larger one is the idle air jet. The smaller one is the main circuit air jet. Go 0.9 mm on the main air jet and 1.15 on the idle air jet. You need to fab a li'l insert in order to remove the original idle air jet and install a new one. You can use a small screw remover to pull out the li'l bronze insert on the idle air jet. (this is to be performed on the two barrels) Do that trick and then tell me. Also if you enlarge both your main air jets to 0.9mm use a 54 jet on the driver side and a 50 on the passg side of the metering block, and get a #28 accel pump shooter. |
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| Author: | slantyslanterstien [ Wed Apr 27, 2005 3:41 pm ] |
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Where are these jets? are they on top of the metering block? do i have to drill them out? |
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| Author: | argentina-slantsixer [ Wed Apr 27, 2005 9:43 pm ] |
| Post subject: | |
they are in the main body, above the venturi, just near the accel pump shooter. maybe this pic can lighten up my words
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| Author: | slantyslanterstien [ Thu Apr 28, 2005 2:34 pm ] |
| Post subject: | |
Thanks for the pics. Do the jets just pop out? The carb I have on the truck is a used one and the main air jets are missing. I have another used holley which still has them in there, but the idle air jets in both of them are bigger than 1.15. Where would I get new ones? And how do them come out? |
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| Author: | argentina-slantsixer [ Thu Apr 28, 2005 6:30 pm ] |
| Post subject: | |
You ain't need to pop out the main air jets. just ream them to .9 or .75 if you wanna keep mpg a li'l bit more friendly to your bank account.  about the idle air jets, they always are kinda way too big. Especially being not present (I take that you have 2 large holes where the idle air jets are supposed to be, ain't that true?) Those are bronze inserts, you can line'em up in a small lathe, using solid brass or bronze stock (even aluminium stock can do the work) you can drill 'em with a 2.25 mm drill and then if they didn't loosened up you can remove them with a screw extractor. Then, you can use a tapered reamer and line a tapered insert (it would be more easy to press fit) or just measure the bore and line up another insert .03 mm larger in diameter and hammer it on (using a pin remover tool that has the adequate size). one word of advice, bore your new insert just a tad less than the size I recommended (use a 80 wire gauge drill) and then ream it till it idles nice (you'll have to take the thing appart 2 or 3 times but once you do so she'll be perfectly dialed in)don't hesitate on droppin a PM if you need further assistence, I can even take special snaps if you need to "see" any particular part of the work) |
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| Author: | slantyslanterstien [ Tue May 24, 2005 8:18 pm ] |
| Post subject: | |
I tried a carb body with air jets closer to the size and there was no difference. I tuned it some more and it backfires through the exaust a lot less but the flat spot is still there. When I try to accelerate it just boughs down and sputters and won't go and backfires through the carb. I know I should have put a performance cam in it but when I was going through the motor I did not know of this wed site. Have any of you done what I did to the motor? And if so what carb did you use? |
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| Author: | argentina-slantsixer [ Tue May 24, 2005 10:32 pm ] |
| Post subject: | |
So far so good. a) ream the air jet to my specs B) use a 54 main jet on the drivers side of the metering block, a 52 on the closer to the valvle cover side. C) advance your timing to at least 10 BTDC. You can go 15 if you rcurve. D) ream your accel pump jets accordingly with your jet sizes. Start with a 25, then ream a lil the passg side shooter and some more the other side (the one that has the bigger fuel main jet) tell me how ya doin with this. |
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| Author: | Dennis Weaver [ Wed May 25, 2005 8:40 am ] |
| Post subject: | Correct Holley Tuning Procedure |
This is the only way to tune a holley properly: 1) Drain fuel from carb (most of it already leaked out, so there won't be much). 2) Remove lid from trash can. 3) Vigorously discard holley in can. 4) Cover holley with old newspapers or rotting vegatables to mask the offensive odor (and so no hapless winos will find it and think they've actually stumbled upon something of value). 5) Re-affix trash can lid. 6) Push can to curb. D/W |
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| Author: | argentina-slantsixer [ Wed May 25, 2005 11:58 am ] |
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c'mon dennis... we all know that there's no such thing as holley correct dialing in or tuning procedure. Holleys can't be tuned. period. is like finding the holy grial... you're always this close and it fades away... one thing's for sure... you'll end up finding the holy crap trying to tune up a holley. I'll tell you this: I came across an US holley last week... man, that factory sux. I'm begining to think that your american holleys are produced with pride in INDIA... I'll swap my 1 barrel soon and I'l send it to you as I promised, and you'll see what I'm talking about. |
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| Author: | slantyslanterstien [ Wed May 25, 2005 7:26 pm ] |
| Post subject: | |
How do you ream something that size?, those things are tiny. Yeah its a pain to dump all the gas out when you take the fuel bowl off each time. I was looking though my fathers back room where keeps all his car parts and I found 2 holleys that looked terrible but I thought I'd take them apart to see what kind of jets were in them. I took all the srews out of the fuel bowl but it was stuck so I tapped it with my screwdriver and it fell off along with it a bunch old fuel (only holley I seen that didn't leak) of corse it it all fell on my pants. That gas must have been 20 years old and stunk awful bad. Burning the holley is a good idea. |
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