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Re: Edelbrock accelerator pump adjustment question [Re: David_Trimble] #1300597
09/28/12 09:46 PM
09/28/12 09:46 PM
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RapidRobert Offline
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the vertical spacing is good as the tip is well into the range of the vertical wall & the lateral clearance seems alot in the pic but you said it was 1/16-1/32" which is acceptable & I'm sure the Echlin MO3000 .060" longer rotor helped with that. You can actually reduce it to .010-.015" lateral clearance by soldering material to extend it or bolting on part of a tip from a junk rotor but that requires dead on tight bushings tho any excessive gap that the spark has to jump outside the cylinder raises the required voltage & is a waste but we're plenty good for now & lets hope it was the cause of the stumbling. Do save that cap in the pic & drill a 1/2" hole in the top flat 2/3 of the way between the center post & the #1 cap terminal so we can check rotor phasing with a timing light when we get it running which'll be the 3rd clearance we want blueprinted (1) lateral clearance (2) rotor height (3) rotor phasing. Actually a 4th one is the height (sideways) of each reluctor tooth


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Re: Edelbrock accelerator pump adjustment question [Re: RapidRobert] #1300598
09/29/12 11:06 AM
09/29/12 11:06 AM
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Quote:

the vertical spacing is good as the tip is well into the range of the vertical wall & the lateral clearance seems alot in the pic but you said it was 1/16-1/32" which is acceptable & I'm sure the Echlin MO3000 .060" longer rotor helped with that. You can actually reduce it to .010-.015" lateral clearance by soldering material to extend it or bolting on part of a tip from a junk rotor but that requires dead on tight bushings tho any excessive gap that the spark has to jump outside the cylinder raises the required voltage & is a waste but we're plenty good for now & lets hope it was the cause of the stumbling. Do save that cap in the pic & drill a 1/2" hole in the top flat 2/3 of the way between the center post & the #1 cap terminal so we can check rotor phasing with a timing light when we get it running which'll be the 3rd clearance we want blueprinted (1) lateral clearance (2) rotor height (3) rotor phasing. Actually a 4th one is the height (sideways) of each reluctor tooth




Yea- sorry about the pics. I know it's hard to see things - my camera isn't good at close-ups....

Right- I was thinking of drilling out that sensor tower for the rotor phasing check - I think that's between the coil wire tower and the #1 tower. The drill press should make short work out of that....


As for the rotor tip clearances, I agree- I think we're at the point where we need to see if any of the changes did any good for the engine and go at it from there.

Hopefully I'll find that gauge today- if not, I'll have to order a set from someone on the Internet (noone in town seems to sell plastic gauges...)


'69 Dodge Charger R/T
Re: Edelbrock accelerator pump adjustment question [Re: David_Trimble] #1300599
09/29/12 02:42 PM
09/29/12 02:42 PM
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RapidRobert Offline
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Quote:

Hopefully I'll find that gauge today- if not, I'll have to order a set from someone on the Internet (noone in town seems to sell plastic gauges...)


actually you could probably improvise with something non metallic that's close to the right thickness. (my Nebraska drivers license is .033" & you said we need .035" right)


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Re: Edelbrock accelerator pump adjustment question [Re: RapidRobert] #1300600
09/29/12 04:45 PM
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David_Trimble Offline OP
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Ah- good idea. I have a micrometer..... got tons of plain sheet plastic, so I'll just have a look around. It's raining today so I can't get to the shed so I'll do that instead

Edit: Looks like the gap is supposed to be .030", according to Google...

Last edited by David_Trimble; 09/29/12 04:59 PM.

'69 Dodge Charger R/T
Re: Edelbrock accelerator pump adjustment question [Re: David_Trimble] #1300601
09/30/12 05:09 PM
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Well I went thru my plastic for a makeshift feeler gauge- found one that measured .032" on the first try so I went with that. So the Pertronix sensor got gapped and got the distributor back into the car. Started it up and let it idle for ~10 minutes to let it warm up and to report:

1) After warm-up, I had a very smooth idle and the off-idle acceleration stumble is almost completely gone. I seem to feel a slight (very slight) hesitation but I don't know if it's my imagination or if I just need to re-fine-tune the engine again (I did not reset the initial timing on the distributor - I just lined it up with a set of marks I made before I pulled it- but I imagine I will have to since I've effectively changed the dwell). The idle is much more stable, too- it was idling at around 500-550rpm once it warmed up (and it's NEVER idled smoothly at that speed before) and I had checked the RPM- I reset it to 750rpm and reset the carb idle screws to 1-1/2 turns out as I'll have to fine tune them, too.

2) In another thread I had mentioned a 'sticky' accellerator pedal, which I did not experience while doing the above. I'm not 100% sure it's gone away and if I inadvertanly fixed that issue I certainly don't understand how what I did would've affected that issue.

Anyway, in a day or 2 I'll get around to doing the fine-tuning (as well as doing the rotor phasing test) and I'll report in again.


'69 Dodge Charger R/T
Re: Edelbrock accelerator pump adjustment question [Re: David_Trimble] #1300602
09/30/12 07:43 PM
09/30/12 07:43 PM
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(1) major progress (2) good Karma


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Re: Edelbrock accelerator pump adjustment question [Re: RapidRobert] #1300603
10/02/12 07:29 PM
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Ok this is easy- I tried the rotor phasing test, drilled the hole then swapped out the good cap for the 'test' cap, connected the timing light to #1 wire and hit the rotor with the light while revving the engine.

THe rotor didn't budge Stayed rock steady during the whole process. I'm guessing this means there's something wrong with my vacuum advance? It's connected to the left vacuum port on my Edelbrock (1405), and I think that's the ported vacuum.


'69 Dodge Charger R/T
Re: Edelbrock accelerator pump adjustment question [Re: David_Trimble] #1300604
10/02/12 08:23 PM
10/02/12 08:23 PM
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Only vac adv changes rotor phasing so if it's not functioning then yes the rotor will not move when "frozen" with the light. iirc the passenger side port is ported. How close to straight on was the rotor to the cap terminal? EDIT pull & cap the vac adv hose & see where the rotor points to in the at rest/no vacuum position. Adding the vac adv can will shift the rotor clockwise (on a BB) from that original at rest/no vacuum position however under power (WOT) the rotor will be at the original no vac/at rest position and this is when the required voltage is the greatest so the rotor especially needs to be within range at that point

Last edited by RapidRobert; 10/02/12 09:14 PM.

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Re: Edelbrock accelerator pump adjustment question [Re: RapidRobert] #1300605
10/02/12 09:54 PM
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Quote:

How close to straight on was the rotor to the cap terminal?



As far as I could tell (and remember) it was pointing right at the terminal. If you need to know if it was pointing a little before or after the centerline of the terminal I'll have to take another look (which will have to be tomorrow I'm afraid)

I only blipped the throttle to about 1/3 open- probably got up to around 2500 rpm- didn't try to do a WOT. But even so I would've thought that I'd see at least a little movement? But I'll try it again tomorrow, checking both with and without the vacuum line connected (and plugged when not) and report in then.


'69 Dodge Charger R/T
Re: Edelbrock accelerator pump adjustment question [Re: David_Trimble] #1300606
10/03/12 06:59 PM
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It keeps getting more interesting....

OK- with the vacuum line connected, I noticed that I was wrong before- the rotor seems to be pointing past (towards CW) the terminal. How far it's moved it's hard to describe- I can say that it's moved far enough where the centerline of the rotor is past where I would guesstimate the brass terminal post to be inside the distributor.

Disconnecting and plugging the vacuum line moves the rotor so it's definitely pointing straight at the terminal. That is, the centerline of the rotor intersects the center of the terminal post (or pretty close to it).

So it looks like at idle I'm actually running some advance, which explains a few things :/


'69 Dodge Charger R/T
Re: Edelbrock accelerator pump adjustment question [Re: David_Trimble] #1300607
10/03/12 11:55 PM
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Are you on ported or manifold? If your on ported I'm wondering what's up with that, is your idle speed way too high? If so maybe the timing was skewed. I'm thinking the rotor ain't so far to the right of the terminal under normal high vacuum conditions to effect a miss as wasn't it a stumble when you mashed it which at that point the rotor would be shifted closer to dead center but I cant say for sure how far it is off. You can redrill the slot like Andy did with his machined reluctors way back and there's room for 4 or 5 more slots till you get it dead on. Need a mini drill bit of the right dia and a mini rattail file to break open the hole you drill to the open ID. Harbor Freight has the file kit for next to nothing but get the best drill bit you can


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Re: Edelbrock accelerator pump adjustment question [Re: RapidRobert] #1300608
10/04/12 08:38 AM
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Quote:

Are you on ported or manifold? If your on ported I'm wondering what's up with that, is your idle speed way too high? If so maybe the timing was skewed. I'm thinking the rotor ain't so far to the right of the terminal under normal high vacuum conditions to effect a miss as wasn't it a stumble when you mashed it which at that point the rotor would be shifted closer to dead center but I cant say for sure how far it is off. You can redrill the slot like Andy did with his machined reluctors way back and there's room for 4 or 5 more slots till you get it dead on. Need a mini drill bit of the right dia and a mini rattail file to break open the hole you drill to the open ID. Harbor Freight has the file kit for next to nothing but get the best drill bit you can



I'm positive I'm on the ported vacuum port- I verified it with the owner's manual. I've kept the idle speed below 1000 rpm (it's adjusted to 750rpm) And yes, at first it had stumbled if I did more than gradually open the throttle, but since I redid the distributor that's mostly gone away, if not completely (oh and by the way this was all done in the garage, not on the street - the car's not streetable just yet) As a thought, I'll take a look at the reluctor to make sure it's seated correctly.

One other idea I had- I heard that the vacuum advance on the distributor is adjustable (by turning a allen wrench through the vacuum port itself) - I'm wondering if it got adjusted when it was recurved and now needs to be dialed back so that it won't advance under whatever vacuum I'm giving it from ported vacuum at idle?


'69 Dodge Charger R/T
Re: Edelbrock accelerator pump adjustment question [Re: David_Trimble] #1300609
10/04/12 10:37 AM
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Yes going CCW with a 3/32" allen wrench slows the onset of the start of the advance curve but the problem is not there, it's the ported nipple, it should have very little or no vacuum at idle, definitely not near enough vac to activate the can no matter where the cans' curve is set at. Can you put a vac gauge on it & see what you do have there. EDIT if it's activating the can it's too much vac (no matter how much it is) at idle on the ported nipple

Last edited by RapidRobert; 10/04/12 11:41 AM.

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Re: Edelbrock accelerator pump adjustment question [Re: RapidRobert] #1300610
10/04/12 12:30 PM
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I've got a vacuum gauge, so yes I can get a reading off the ported vacuum no problem. I'll do that tonite along with the other checks.

So ultimately, it's sounds like I have a defective vacuum can?


'69 Dodge Charger R/T
Re: Edelbrock accelerator pump adjustment question [Re: David_Trimble] #1300611
10/04/12 06:08 PM
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Quote:

it's sounds like I have a defective vacuum can?


The can is good if it ain't damaged and will also hold vacuum & I think we're good there. I'm thinking the inital timing is so far retarded that you have to open the throttle blades way beyond normal to get even a 750 rpm idle speed and that's sending vacuum to the ported nipple. Bump the timing up which'll increase the idle speed & see if you can close down the throttle to get the idle speed back down & see if the ported nipple then has no vacuum which is what we want & is correct functioning


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Re: Edelbrock accelerator pump adjustment question [Re: RapidRobert] #1300612
10/04/12 06:49 PM
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Ok this is easy- and again, confusing....

Readings from the ported vacuum outlet on the carb- these were taken with a cold engine but I don't think this matters as I don't think we were looking for exact readings. But long story short, I was reading about 14-15" Hg with the engine running around 700rpm. Lightly blipping the throttle, the vacuum reading dropped momentarily to around 5"Hg before returning to previous reading.

Unless I'm not understanding something correctly (and that's entirely possible) I would've expected the reverse behavior if everything was running correctly?


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Re: Edelbrock accelerator pump adjustment question [Re: David_Trimble] #1300613
10/04/12 06:59 PM
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that's normal for the manifold vac port on the drivers side but the ported one should have no/ little vac at idle. Eng off, Can you unscrew the idle speed throttle screw till the throttle stops moving (throttle closed) and count the # of turns to get to that point plus it'll easily let you return it to the exact position & see how many turns in it is


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Re: Edelbrock accelerator pump adjustment question [Re: RapidRobert] #1300614
10/04/12 07:36 PM
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Quote:

that's normal for the manifold vac port on the drivers side but the ported one should have no/ little vac at idle. Eng off, Can you unscrew the idle speed throttle screw till the throttle stops moving (throttle closed) and count the # of turns to get to that point plus it'll easily let you return it to the exact position & see how many turns in it is



Almost exactly 2 turns.


'69 Dodge Charger R/T
Re: Edelbrock accelerator pump adjustment question [Re: David_Trimble] #1300615
10/04/12 10:15 PM
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Quote:

Almost exactly 2 turns.


that's normal. I'm out of ideas (for now)


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Re: Edelbrock accelerator pump adjustment question [Re: RapidRobert] #1300616
10/04/12 11:42 PM
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Quote:

that's normal. I'm out of ideas (for now)



Yea- the only thing I can think of to try is with the vacuum gauge connected to the ported vacuum, lower the engine speed by turning down the idle set screw until the engine dies and watch the gauge to see if the vacuum drops off significantly at any point before the engine dies. But if I'm only 2 turns open to begin with, I'm not hopeful... Other than that I'd have to conclude that if I'm not getting proper vacuum from that port then my carb must be defective.

Is it possible that there was a design change with the Performer series at one time where they swapped ports? I know that's a long shot but it's the only remotely plausible explaination Tomorrow, for grins I'll check the vacuum on what the manual says is the 'full vacuum' port. MAYBE the manual's simply incorrect- but I seem to remember seeing several posts here confirming what the manual said....

Edit: In googling around in other non-Mopar forums on the question of Edelbrock ported vacuum, someone had mentioned that there were 2 types of distributors vacuum advances - one would advance with increase of vacuum, the other would advance with decrease of vacuum. I'm assuming Mopar distributors use the increase vacuum/increase advance setup. In that case the carb might be ok- but this particular model (1405) wasn't meant to work on Mopars? Personally I find that hard to believe, but it would explain what I'm seeing on the ported vacuum readings.

Last edited by David_Trimble; 10/05/12 12:06 AM.

'69 Dodge Charger R/T
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