Re: Jetting& Altitude
[Re: pjc360]
#1644725
07/25/14 08:35 AM
07/25/14 08:35 AM
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Joined: Jan 2003
Posts: 5,443 Indiana
YO7_A66
master
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master
Joined: Jan 2003
Posts: 5,443
Indiana
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""unless .020 idle feed restrictors are too big. But that's the smalles idle feed restrictor quick fuel sells"" ""I received the .020 idle feed restrictors this afternoon. I installed them/now it wont idle on it's own/But I did hold the throttle steady at about 2500 rpm and I watched the hedders and they started to glow red again."" ""Before doing that I took all my plugs out and I had 2 fouled plugs."" --------------------------------------------- Which side is the header glowing red, or is it both sides? Which cylinders have the fouled plugs? Is it always the same locations? I think that there is a reason why QF does not sell any IFR's below .020.
Since you have used .020-.033 IFR's and you are still getting glowing header(s) at 2500rpms (while using 64 main jets), I am leaning towards the issues that you are having are not carb related. You might start a new thread asking about your glowing headers at 2500rpms. If you have a leaking intake gasket (between the head and the intake), this could cause the intake to be sucking in air causing a lean condition (red header(s)). This same issue could cause the exhaust to pop and also certain plugs to be "oil-fouled" (not fuel fouled). I just suggest that you take a step back and make sure that there is nothing besides the carb that could be causing the glowing header issue.
Are the fouled plugs always the same cylinders? If so, maybe you have bad spark plugs wires that are not firing which could cause those cylinders to be filling with fuel causing the red headers. The bad wires could also cause the popping out the exhaust too. Ohm out the wires on the cylinders which you are finding the fouled plugs to see what they measure.
1970 YO7 A66 [Canadian Export] F8 Challenger 340 (Currently in shop for stroker assy.)
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Re: Jetting& Altitude
[Re: Red 79]
#1644727
07/25/14 07:47 PM
07/25/14 07:47 PM
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Joined: Nov 2011
Posts: 653 montana
pjc360
OP
mopar
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OP
mopar
Joined: Nov 2011
Posts: 653
montana
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No it is not the same plugs that are becoming fouled. And they are not oil fouled, they are fuel fouled, They look just like the inside of a chimney. Normally there is a plug fouled on each side. Both sides of the hedders are glowing, mainly the 2 middle pipes on each hedder. The plugs that were fouled yesterday were plug 6 and plug 7. I removed all of my plug wires and they all ohm out at 40 ohms of resistance per foot, I jut got these plug wires for Christmas and they have maybe 500 miles on them, MAYBE. Tonight I am going to take out the high speed air bleeds and start it and let it idle on the fast idle circuit and see what happens. If they still light up I will remove the vaccum advance from the manifold source and put it on the ported source, altho I don't see how this could cause the hedders to glow, at 2000 to 2500 rpm the distributer is going to see the same amount of vaccum from the manifold port and ported port on the carb. If it still does it after this I'm going to buy a wideband even though I really cant afford it and wait until I get it and then I will get it hooked up and i'll be able to tell you guys what the wideband says the mixture is. I really think this is fuel related, the plugs look black and sooty just like the inside of a chimney looks like. I did another compression test with the engine warm and ignition dis-abled and the carb all the way open and every cylinder reads 150 psi. If the high speed air bleeds aren't the cause of this then I give up and will get a wideband. I am starting to think that maybe the high speed air bleeds are allowing the mains to come inn to soon which is adding fuel to the idle circuit while it's idling on the fast idle. I have read that the .028 high speed air bleeds are actually quite small and make the mains come on pretty quick. I'm going to put smaller main jets in and see if that changes anything too, if it does then that might indicate that the high speed air bleeds are coming on too soon. I have checked for vaccum leaks, I can not find one. All of my vaccum lines are brand new, my intake manifold gasket is brand new and my intake manifold is brand new and I checked it for flatness with a straight edge. I have sprayed carb cleaner with the engine idling all around the intake manifold and the carburetor and I don't hear a change in the idle.
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Re: Jetting& Altitude
[Re: pjc360]
#1644731
07/25/14 10:24 PM
07/25/14 10:24 PM
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Joined: Jan 2003
Posts: 5,443 Indiana
YO7_A66
master
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master
Joined: Jan 2003
Posts: 5,443
Indiana
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You found that the .020's are way too lean if you could not keep it idling. Good test. There is not much difference between the .030's and the .031's. I would say just pick one. I think you found that it idled fairly well on .065 IAB's. If so, then I would go with that. Lets say that you test the .030 IFR's and the .065 IAB's. If this idles well, then start with changing the HSAB's. Get it idling again first at your normal idle rpm, then move on to leaning out the HSAB's.h Lets say that the .028 HSAB's are too rich which are bringing on your mains too soon. This may be what is causing the rich condition (as long as the plug wires are good, there are no vacuum or intake leaks). I would make a guess at low to mid 30's on the HSAB's for your test. You just need to keep testing!
Note: My .033 HSAB's bring my mains in right around the 2500-2700rpm range. Remember that the main jets and the MAB's are a team and they work together. One could be fine while the other could be off. I would suggest leave the 64's in there and lean out the .028's.
Last edited by YO7_A66; 07/25/14 10:31 PM.
1970 YO7 A66 [Canadian Export] F8 Challenger 340 (Currently in shop for stroker assy.)
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Re: Jetting& Altitude
[Re: pjc360]
#1644733
07/26/14 03:32 AM
07/26/14 03:32 AM
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Joined: Nov 2011
Posts: 653 montana
pjc360
OP
mopar
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OP
mopar
Joined: Nov 2011
Posts: 653
montana
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I am extremely happy to announce that I found the culprit to the overly rich mixture at fast idle, from 1500 rpm to 2500 rpm. It was indeed the high speed air bleeds, for the most part. I removed all 4 high speed air bleeds and waited until it got dark. Fired it up with the choke/fast idle on and I let it idle for about 5 minutes on the fast idle. I heard a few faint pops out the exhaust here and there, but nothing compared to how it was before. I decided to look at the hedders after about 5 minutes of it idling on the fast idle. On the drivers side nothing was glowing at all, on the passenger side the two last hedder pipes running off of cylinder 6 and 8 were slightly showing a little bit of red, it wasn't glowing bright orange like it was when the high speed bleeds were in place, but you could see a little red, not glowing, but you could see it. So that leads me to believe the idle circuit is a little on the rich side with the .030 idle feed restrictors and the .070 idle air bleeds. I was thinking I would order one more .028 idle feed restrictor because I have 3 .028 idle feed restrictors I broke the fourth one. And some .033 and some .035 high speed air bleeds. Then I was thinking when that arrived I would install all four .028 idle feed restrictors along with the .070 idle air bleeds and then install the .033 high speed bleeds and see what that does. With the high speed bleeds completely removed, I had to of been idling strictly on the idle feed restrictors and the idle air bleeds tonight with it on the fast idle, and for 2 of the hedder pipes on cylinder 6 and 8 to slightly light up red shows me I have the idle mixture a tad too rich. So I think going with the .028 idle feed restrictors and the bigger .033 high speed air bleeds is a step in the right direction. I will also check my plugs before firing it up again to make sure I didn't foul any. I only ran it for about 10 minutes total today, but it doesn't take much to foul a plug in my expierence.
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Re: Jetting& Altitude
[Re: pjc360]
#1644734
07/26/14 10:43 AM
07/26/14 10:43 AM
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Joined: Jan 2003
Posts: 5,443 Indiana
YO7_A66
master
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master
Joined: Jan 2003
Posts: 5,443
Indiana
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Good job testing! Now you may want to test something that was mentioned by Jeremiah: ""At 4200 ft above sea level I usually start out with .075 or .080 IAB's in the Quickfuel stuff."" Your IAB's will affect the A/F ratio way up into after the main circuit is starting in. If you have some larger IAB's or you have some drill bits, I would test the above statement. You could just put some larger IAB's up on the Primary side for testing if you only want to drill out a pair. Then if it works, then drill out a second pair for the secondary side. I would suggest leaving in the .030 IFR's and start testing with the larger IAB's. If it starts good, and it gets rid of the glowing headers, then you are doing the same as if you were swapping in smaller IFRS. As long as your metering screws don't get too far out with the larger IAB's, you should be fine. It would still be a good idea to buy the .036/.039ish sizes of MAB's for your testing too. You could also test with some smaller main jets than your current 64's since you found removing the MAB's leaned out the issue. Nice job! You have put in allot of effort to try and figure this out. Some people would have just bought another carb instead of blaming their own lack of effort. Since you are at a much higher altitude than most, you have a little extra hurdle to jump. I just hope you are keeping good notes! You will be flying through this tuning crapt once you get your wideband kit one day.
1970 YO7 A66 [Canadian Export] F8 Challenger 340 (Currently in shop for stroker assy.)
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Re: Jetting& Altitude
[Re: pjc360]
#1644735
07/26/14 02:17 PM
07/26/14 02:17 PM
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Joined: Aug 2003
Posts: 43,157 Bend,OR USA
Cab_Burge
I Win
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I Win
Joined: Aug 2003
Posts: 43,157
Bend,OR USA
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Quote:
I am extremely happy to announce that I found the culprit to the overly rich mixture at fast idle, from 1500 rpm to 2500 rpm. It was indeed the high speed air bleeds, for the most part. I removed all 4 high speed air bleeds and waited until it got dark. Fired it up with the choke/fast idle on and I let it idle for about 5 minutes on the fast idle. I heard a few faint pops out the exhaust here and there, but nothing compared to how it was before. I decided to look at the hedders after about 5 minutes of it idling on the fast idle. On the drivers side nothing was glowing at all, on the passenger side the two last hedder pipes running off of cylinder 6 and 8 were slightly showing a little bit of red, it wasn't glowing bright orange like it was when the high speed bleeds were in place, but you could see a little red, not glowing, but you could see it. So that leads me to believe the idle circuit is a little on the rich side with the .030 idle feed restrictors and the .070 idle air bleeds. I was thinking I would order one more .028 idle feed restrictor because I have 3 .028 idle feed restrictors I broke the fourth one. And some .033 and some .035 high speed air bleeds. Then I was thinking when that arrived I would install all four .028 idle feed restrictors along with the .070 idle air bleeds and then install the .033 high speed bleeds and see what that does. With the high speed bleeds completely removed, I had to of been idling strictly on the idle feed restrictors and the idle air bleeds tonight with it on the fast idle, and for 2 of the hedder pipes on cylinder 6 and 8 to slightly light up red shows me I have the idle mixture a tad too rich. So I think going with the .028 idle feed restrictors and the bigger .033 high speed air bleeds is a step in the right direction. I will also check my plugs before firing it up again to make sure I didn't foul any. I only ran it for about 10 minutes total today, but it doesn't take much to foul a plug in my expierence.
How often do you let your motor run at 1500 to 2500 RPM in nuetral for more than 2 to 3 minutes on the choke? I'm thinking your fighting a fight that doesn't need fighing BTW, if it is dripping fuel into the motor from the venturi boosters at those RPM you are off the idle and transition circuits and into the mains Dude, you are getting a education Now get to having some fun, go drive that rascal like you stole it
Mr.Cab Racing and winning with Mopars since 1964. (Old F--t, Huh)
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Re: Jetting& Altitude
[Re: pjc360]
#1644739
07/26/14 09:51 PM
07/26/14 09:51 PM
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Joined: Jan 2003
Posts: 5,443 Indiana
YO7_A66
master
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master
Joined: Jan 2003
Posts: 5,443
Indiana
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Definitely test the .039 HSAB's but don't sweat changing from the 64 to 65 jets (just yet). ONE CHANGE AT A TIME! Note: I don't think that they would be too lean in your case. I swap back and fourth from .036 to .039's on my secondaries as the outside temps change to tune my WOT A/F readings. McMasterCarr.com is your friend. They have drill bits in all of the small sizes that you will need. I bought a dozen or so from them so that I could drill out my IFR's/IAB's/ and MAB's. http://www.mcmaster.com/#standard-drill-bits/=t0eh03
Last edited by YO7_A66; 07/26/14 10:06 PM.
1970 YO7 A66 [Canadian Export] F8 Challenger 340 (Currently in shop for stroker assy.)
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Re: Jetting& Altitude
[Re: pjc360]
#1644741
07/27/14 01:08 AM
07/27/14 01:08 AM
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Joined: Jan 2003
Posts: 5,443 Indiana
YO7_A66
master
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master
Joined: Jan 2003
Posts: 5,443
Indiana
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Make sure to get us an update!
1970 YO7 A66 [Canadian Export] F8 Challenger 340 (Currently in shop for stroker assy.)
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