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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Posts: 36,041 Lincoln Nebraska
RapidRobert
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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]
#1300600
09/29/12 04:45 PM
09/29/12 04:45 PM
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David_Trimble
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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
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Re: Edelbrock accelerator pump adjustment question
[Re: David_Trimble]
#1300601
09/30/12 05:09 PM
09/30/12 05:09 PM
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David_Trimble
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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
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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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Posts: 36,041 Lincoln Nebraska
RapidRobert
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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
10/02/12 07:29 PM
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David_Trimble
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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
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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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RapidRobert
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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.
live every 24 hour block of time like it's your last day on earth
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Re: Edelbrock accelerator pump adjustment question
[Re: David_Trimble]
#1300606
10/03/12 06:59 PM
10/03/12 06:59 PM
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David_Trimble
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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
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Re: Edelbrock accelerator pump adjustment question
[Re: David_Trimble]
#1300607
10/03/12 11:55 PM
10/03/12 11:55 PM
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RapidRobert
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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
live every 24 hour block of time like it's your last day on earth
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Re: Edelbrock accelerator pump adjustment question
[Re: David_Trimble]
#1300609
10/04/12 10:37 AM
10/04/12 10:37 AM
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Posts: 36,041 Lincoln Nebraska
RapidRobert
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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.
live every 24 hour block of time like it's your last day on earth
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Re: Edelbrock accelerator pump adjustment question
[Re: RapidRobert]
#1300610
10/04/12 12:30 PM
10/04/12 12:30 PM
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David_Trimble
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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
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Re: Edelbrock accelerator pump adjustment question
[Re: RapidRobert]
#1300612
10/04/12 06:49 PM
10/04/12 06:49 PM
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David_Trimble
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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?
'69 Dodge Charger R/T
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Re: Edelbrock accelerator pump adjustment question
[Re: David_Trimble]
#1300613
10/04/12 06:59 PM
10/04/12 06:59 PM
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Posts: 36,041 Lincoln Nebraska
RapidRobert
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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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