Re: 340 Six Pack vacuum advance
[Re: Aar1064]
#2454602
02/20/18 03:45 PM
02/20/18 03:45 PM
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Joined: Aug 2003
Posts: 43,124 Bend,OR USA
Cab_Burge
I Win
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I Win
Joined: Aug 2003
Posts: 43,124
Bend,OR USA
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It sounds like you have the vacuum advance hook into manifold vacuum port instead of above the throttle plates for ported vacuum like they came stock Which carb numbers are you using, OEM Holley or after market carbs like the BG six shooters or ?
Mr.Cab Racing and winning with Mopars since 1964. (Old F--t, Huh)
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Re: 340 Six Pack vacuum advance
[Re: Aar1064]
#2454646
02/20/18 04:55 PM
02/20/18 04:55 PM
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Joined: Nov 2003
Posts: 36,040 Lincoln Nebraska
RapidRobert
Circle Track
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Circle Track
Joined: Nov 2003
Posts: 36,040
Lincoln Nebraska
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we need all related specs; initial timing. in hg vacuum. ported or manifold. how much timing when you plug the hose in. Rotor phasing OK?
live every 24 hour block of time like it's your last day on earth
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Re: 340 Six Pack vacuum advance
[Re: Cab_Burge]
#2454722
02/20/18 07:07 PM
02/20/18 07:07 PM
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Joined: May 2013
Posts: 282 Ashland City, Tennessee
Aar1064
OP
enthusiast
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OP
enthusiast
Joined: May 2013
Posts: 282
Ashland City, Tennessee
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It sounds like you have the vacuum advance hook into manifold vacuum port instead of above the throttle plates for ported vacuum like they came stock Which carb numbers are you using, OEM Holley or after market carbs like the BG six shooters or ? OEM original Holley carbs restored by Scott. It's plugged into the ported one on center carb.
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Re: 340 Six Pack vacuum advance
[Re: RapidRobert]
#2454726
02/20/18 07:24 PM
02/20/18 07:24 PM
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Joined: May 2013
Posts: 282 Ashland City, Tennessee
Aar1064
OP
enthusiast
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OP
enthusiast
Joined: May 2013
Posts: 282
Ashland City, Tennessee
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we need all related specs; initial timing. in hg vacuum. ported or manifold. how much timing when you plug the hose in. Rotor phasing OK? I need to start out by saying that this is a fresh restoration and I'm working out a few kinks. Engine maybe has 15 hours on it. Stock build 340 TA with original carbs. Initial @18 ported with hose plugged in it's at 18* when it settles down to an idle. After reading more about it and talking to Jeff this morning, it may not be the vacuum just a carb adjustment issue. I've followed every guide I've found related to these carbs in particular the one that Tom Quad put out but I'm getting nowhere. I've got all the gauges needed to perform a top quality tune and the only thing missing is the experience. Lol. From what I've read about transient (run) and idle circuits it seems it's having a tough time moving from run to idle. When I gas and release it, it will set at around 1400 to 1500 RPM's and crawl back down and may or may not idle. Takes about 10 seconds or so. Scott restored them and outboard fuel air screws are setting where they were when they left his shop. I have no hair left after this weekend. Argh
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Re: 340 Six Pack vacuum advance
[Re: Aar1064]
#2454747
02/20/18 08:59 PM
02/20/18 08:59 PM
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Joined: Nov 2003
Posts: 36,040 Lincoln Nebraska
RapidRobert
Circle Track
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Circle Track
Joined: Nov 2003
Posts: 36,040
Lincoln Nebraska
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it almost sounds like the throttle shaft/butterflies are hanging up in the bores. I'm assuming the dist weights ain't sticking. yes this hobby has made more men go bald than any other (but we wouldn't trade it for nuthin).
live every 24 hour block of time like it's your last day on earth
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Re: 340 Six Pack vacuum advance
[Re: Aar1064]
#2454853
02/20/18 11:44 PM
02/20/18 11:44 PM
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Joined: Aug 2003
Posts: 43,124 Bend,OR USA
Cab_Burge
I Win
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I Win
Joined: Aug 2003
Posts: 43,124
Bend,OR USA
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It sounds like you have the vacuum advance hook into manifold vacuum port instead of above the throttle plates for ported vacuum like they came stock Which carb numbers are you using, OEM Holley or after market carbs like the BG six shooters or ? OEM original Holley carbs restored by Scott. It's plugged into the ported one on center carb. If my memory is serving me correct, it's been over 30 yrs since I worked on a stock set of OEM Holley 340 six pack carbs , the vacuum advance hose should be on the nipple on the passenger side of metering block, not on any other one I've work on a bunch of 440 six packs since then but not in the last 5 yrs Six packs rock when set up correctly, no matter what the doubters say
Mr.Cab Racing and winning with Mopars since 1964. (Old F--t, Huh)
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Re: 340 Six Pack vacuum advance
[Re: RapidRobert]
#2455064
02/21/18 01:42 PM
02/21/18 01:42 PM
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Joined: May 2013
Posts: 282 Ashland City, Tennessee
Aar1064
OP
enthusiast
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OP
enthusiast
Joined: May 2013
Posts: 282
Ashland City, Tennessee
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Checked butterflies last night and they are closing all the way. Weights shouldn't be sticking because of fresh rebuild by Jeff @ Advanced Distributors. With vacuum unplugged from distributor, engine idles down correctly.
I also checked for vacuum leaks and didn't find any.
Last edited by Aar1064; 02/21/18 01:51 PM.
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Re: 340 Six Pack vacuum advance
[Re: Aar1064]
#2455090
02/21/18 02:37 PM
02/21/18 02:37 PM
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Joined: Nov 2003
Posts: 36,040 Lincoln Nebraska
RapidRobert
Circle Track
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Circle Track
Joined: Nov 2003
Posts: 36,040
Lincoln Nebraska
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With vacuum unplugged from distributor, engine idles down correctly. I also checked for vacuum leaks and didn't find any. that tells me that it is dist related, either a vac leak as of yet undiscovered or weights hanging up. I'm assuming you've vacuum pumped the can/hose & I would go inside the dist & go over it.
live every 24 hour block of time like it's your last day on earth
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Re: 340 Six Pack vacuum advance
[Re: Aar1064]
#2455116
02/21/18 03:28 PM
02/21/18 03:28 PM
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Joined: Jan 2003
Posts: 6,840 The Swamp
Sixpak
master
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master
Joined: Jan 2003
Posts: 6,840
The Swamp
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Make sure the fast idle cam adjustment on the center carb is correct. On a sixpak carb it's not a screw adjustment - you have to physically bend a sheet metal tab that contacts the cam in order to move it. There's a little slot in the part to insert a small screwdriver to bend the link. I had a similar issue where I could not get a 340 sixpak to behave at idle. Found that the fast idle cam was getting hung up on the linkage meant to engage it. Some careful adjustments by bending the link fixed it. Make sure the choke is working and the choke pull off is working too. Your car MUST idle off of all 3 carbs, and not just the center carb. That means adjusting the idle on all 3 carbs in order to get it to idle properly. If your idle rpm is much above 1000 rpm you may start pulling vacuum thru the port to the distributor. Insure the fast idle cam isn't hanging up, then end carbs are closed at idle (adjust linkage properly) then adjust the idle mixture screws, starting at 1 5/8 turns out on all 3 carbs for a starting point. Do all adjustments with vacuum hose to distributor disconnected. I found on that same setup the best idle quality I got was having all three carbs have the idle mixture screws turned out 1 5/8 turns. Use that as a start and adjust each mixture screw on the center, and end carbs by covering the air bleed nearest to that mixture screw and checking the idle quality. Covering the bleed should have no effect on idle rpm. If the rpm falls it's too fat, turn in 1/8 turn and try again. Speeds up means it's too lean, turn out 1/8 turn and try again. You may have to take the back carb off to get at the mixture screws. I like to adjust the front carb so it's working well and then swap the front carb to the back. Once you get it to idle cleanly around 950 - 1000 rpm, hook the hose up, then adjust the center carb idle screw; the one on the long arm that usually contacts the idle solenoid, to lower the idle if it picks up.
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Re: 340 Six Pack vacuum advance
[Re: Sixpak]
#2455711
02/22/18 05:12 PM
02/22/18 05:12 PM
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Joined: Jan 2010
Posts: 1,442 NW Chicago suburban area
Mopar Mitch
pro stock
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pro stock
Joined: Jan 2010
Posts: 1,442
NW Chicago suburban area
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I recommend the PROMAX outboard base plates... allows easy adjustment! Its the way it should've been designed in the first place (at least for the rear where you can't get to it with the carbs installed).
Mopar Mitch
"Road racers and autocrossers go in deeper and come out harder!"... and rain never stops us from having fun with our cars... in fact, it makes us better drivers!
Check out MOPAR ACTION MAGAZINE, August 2006 issue for feature article and specs on my autocross T/A!
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Re: 340 Six Pack vacuum advance
[Re: Mopar Guy]
#2460004
03/02/18 05:36 PM
03/02/18 05:36 PM
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Joined: Jan 2010
Posts: 1,442 NW Chicago suburban area
Mopar Mitch
pro stock
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pro stock
Joined: Jan 2010
Posts: 1,442
NW Chicago suburban area
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My PROMAX setup offers easy fine tuning; the factory setup does not. My carbs run perfectly. I've never heard any negatives about PROMAX products.
Mopar Mitch
"Road racers and autocrossers go in deeper and come out harder!"... and rain never stops us from having fun with our cars... in fact, it makes us better drivers!
Check out MOPAR ACTION MAGAZINE, August 2006 issue for feature article and specs on my autocross T/A!
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Re: 340 Six Pack vacuum advance
[Re: Tommy D]
#2460108
03/02/18 08:28 PM
03/02/18 08:28 PM
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Joined: Jan 2003
Posts: 15,439 Val-haul-ass... eventually
BradH
Taking time off to work on my car
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Taking time off to work on my car
Joined: Jan 2003
Posts: 15,439
Val-haul-ass... eventually
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I would NOT recomend Pro Max ! ... I've never heard any negatives about PROMAX products. I'll be curious to see if this expands beyond the above two comments.
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