Edelbrock 1806 Tuning
01-29-2011, 05:13 PM
#51
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Join Date: Aug 2010
Location: tn
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When you say on a level surface, how much difference does it make with say going up hill or down hill?
I know all about the float issue. When my car was still an I6 in highschool, that happened alot with rebuilt carbs, until we got a brand new carb.
I have already replaced the needles/seats once. I did that when I put the Edelbrock fuel pump on to replace the Summit brand pump that was putting out way too much pressure. It was around 8 psi. Now its about 6 psi.
I know all about the float issue. When my car was still an I6 in highschool, that happened alot with rebuilt carbs, until we got a brand new carb.
I have already replaced the needles/seats once. I did that when I put the Edelbrock fuel pump on to replace the Summit brand pump that was putting out way too much pressure. It was around 8 psi. Now its about 6 psi.
Stock edelbrock carb pump discharge valve can be overcome by diaphragm pump when 4 wheeling across very steep mountain terrain. My brother installed a special off road pump discharge valve w/ spring in his Jeep.
Did you ever tune idle lean enough to produce a white #1 plug?
01-31-2011, 02:22 AM
#53
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Join Date: Aug 2010
Location: tn
Posts: 889
Pull #1 plug.
If plug is not white then tune carb by ear to leanest smooth idle.
Pull #1 plug again.
If it is white you are at lean idle.
I run between lean idle to 1/2 turn CCW past lean idle.
Run sufficient idle RPM to satisfy your cam shaft oiling requirements.
Don't tune WOT lean.
If plug is not white then tune carb by ear to leanest smooth idle.
Pull #1 plug again.
If it is white you are at lean idle.
I run between lean idle to 1/2 turn CCW past lean idle.
Run sufficient idle RPM to satisfy your cam shaft oiling requirements.
Don't tune WOT lean.
03-10-2011, 02:30 AM
#54
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Join Date: Dec 2008
Location: Texas
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This is more of a curiosity than anything. Has anyone ever adjusted the secondary air valve? Its the part that looks like a choke on the secondaries. This is the only carb I have seen that had this. Apparently the others have a velocity valve. Its purpose is to keep the car from boggin down from a rush of air before there is enough fuel present when the secondaries open.
03-10-2011, 09:14 AM
#55
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Join Date: Oct 2006
Location: Cork, Ireland
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the setting in the user manaul (the base setting) worked perfectly fine for me.
The idea is that in a _holley_ vacuum advance the carb does not allow the secondaries to open until the vacuum in the primary drops. in the edelbrock AVS carbs the secondaries open manually together with the primaries (wit that usual delay). however the engine can't suck through the secondaries until this upper plate opens. It's controlled by vacuum. So again the same thing you need the throttle wide open and load and rpm for the carb to open that secondary "choke plate".
so again, the description in manual for baseline setting works quite well. (somethig like open screw until the flap opens then close by 3 turns ...?) lemme check for you
yep, found it. AVS adjustment:
http://www.edelbrock.com/automotive_.../1000/1802.pdf
ADJUSTING THE AIR VALVE SECONDARY
1. With Torx drive (T15) and flat blade screw driver in place, loosen
Torx screw, make sure flat blade is secure to prevent loss of spring
pressure (See Fig 12).
2. If you lose spring pressure, turn flat blade screw counter-clockwise
until the air valve reaches closed position plus 1-1/2 turns to
achieve the factory setting.
NOTE: Turn only 1 full turn beyond closed position for
1803/1804 factory setting. For single carb applications, set
1803/1804 carburetors to 1-1/2 turns past closed position.
3. The factory setting is the most common setting. If additional tuning
is required, turn the air valve screw counter-clockwise to make the
air valve open later, it is not recommend to go beyond one turn more
than the factory setting, or more than 2-1/2 turns past the closed
Fig. 11 position.
The idea is that in a _holley_ vacuum advance the carb does not allow the secondaries to open until the vacuum in the primary drops. in the edelbrock AVS carbs the secondaries open manually together with the primaries (wit that usual delay). however the engine can't suck through the secondaries until this upper plate opens. It's controlled by vacuum. So again the same thing you need the throttle wide open and load and rpm for the carb to open that secondary "choke plate".
so again, the description in manual for baseline setting works quite well. (somethig like open screw until the flap opens then close by 3 turns ...?) lemme check for you
yep, found it. AVS adjustment:
http://www.edelbrock.com/automotive_.../1000/1802.pdf
ADJUSTING THE AIR VALVE SECONDARY
1. With Torx drive (T15) and flat blade screw driver in place, loosen
Torx screw, make sure flat blade is secure to prevent loss of spring
pressure (See Fig 12).
2. If you lose spring pressure, turn flat blade screw counter-clockwise
until the air valve reaches closed position plus 1-1/2 turns to
achieve the factory setting.
NOTE: Turn only 1 full turn beyond closed position for
1803/1804 factory setting. For single carb applications, set
1803/1804 carburetors to 1-1/2 turns past closed position.
3. The factory setting is the most common setting. If additional tuning
is required, turn the air valve screw counter-clockwise to make the
air valve open later, it is not recommend to go beyond one turn more
than the factory setting, or more than 2-1/2 turns past the closed
Fig. 11 position.
Last edited by kalli; 03-10-2011 at 09:35 AM.
03-14-2011, 09:13 PM
#57
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Join Date: Dec 2008
Location: Texas
Posts: 4,462
Thanks Kalli, thats interesting. I probably will not mess with it, since I don't seem to be having problems with that. I just have never dealt with it before. I would like to see if it opens all the way with the car running under heavy throttle.
Last edited by tx65coupe; 03-18-2011 at 04:00 AM.
03-15-2011, 12:58 PM
#58
6th Gear Member
Join Date: Oct 2006
Location: Cork, Ireland
Posts: 6,417
the seondaries in a edelbrock always will. however if that top plate will open and how far ... i don't know how you would want to find out :-)
You could always try adjust half turn in either direction to see if it makes a difference. if it doesn't seem to make problems, leave it at what it is.
You could always try adjust half turn in either direction to see if it makes a difference. if it doesn't seem to make problems, leave it at what it is.
03-18-2011, 04:01 AM
#59
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Join Date: Dec 2008
Location: Texas
Posts: 4,462
Yeah there is really no way to do that. It will rev to fast in neutral. The only way to see, I guess would be driving with the hood and air cleaner off. LOL...
I might try adjusting it just a bit and see if anything changes.
I might try adjusting it just a bit and see if anything changes.
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