Re: Lash in the distributor drive
[Re: INTMD8]
#3047025
06/01/22 11:31 AM
06/01/22 11:31 AM
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Joined: Jan 2003
Posts: 3,031 Erda, UT
67Charger
OP
master
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OP
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Joined: Jan 2003
Posts: 3,031
Erda, UT
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I understand you're thinking that it's stack up tolerances (and may be), just saying I wouldn't rule out the current distributor/ignition system as it seems that's a common issue observed among Pro Flo efi users. The measurements I posted this morning nearly eliminate it being strictly mechanical. The lash only accounts for 6° total timing movement. RFI and the MSD Digital 6+ are the prime suspects currently.
11.33 @ 118.46 on motor 10.75 @ 125.35 w/ a little spray Now, high Speed Open Road Racing - Silver State Classic Challenge, Nevada Open Road Challenge, Big Bend Open Road Race Rocky Mountain Race Week 2020, 2022 2.0, Sick Week 2023
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Re: Lash in the distributor drive
[Re: 67Charger]
#3047138
06/01/22 04:12 PM
06/01/22 04:12 PM
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Joined: Jan 2003
Posts: 3,031 Erda, UT
67Charger
OP
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OP
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Joined: Jan 2003
Posts: 3,031
Erda, UT
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As luck would have it, I checked the ProFlo instructions and the ECU will directly run an MSD Baster 2 without an ignition box. That will make that part of the troubleshooting easier anyway. Also means I should fab up a sub-harness to keep in the box of spares along with the Blaster 2 in case the next CDI box kicks the bucket.
11.33 @ 118.46 on motor 10.75 @ 125.35 w/ a little spray Now, high Speed Open Road Racing - Silver State Classic Challenge, Nevada Open Road Challenge, Big Bend Open Road Race Rocky Mountain Race Week 2020, 2022 2.0, Sick Week 2023
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Re: Lash in the distributor drive
[Re: 67Charger]
#3047139
06/01/22 04:16 PM
06/01/22 04:16 PM
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Joined: May 2003
Posts: 6,487 Downtown Roebuck Ont
Twostick
Still wishing...
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Still wishing...
Joined: May 2003
Posts: 6,487
Downtown Roebuck Ont
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As stated, the problem was present with the MP distributor before that, both when it ran the megasquirt and also carbed with a MSD Digital-6. It was terrible enough that I went to the 36-1 and just used the distributor for distribution. Right, so as stated, it was a completely different distributor and ignition system. Close. Multiple distributors (stock, MP (both with advance and locked out for EFI), Edelbrock), multiple ECU's (Megasquirt-2/ProFlo-4) or direct feed from distributor pickup to ignition box (carb'ed), including reversing the p/u wires, but ALWAYS the same Digital 6. I think you may have found the culprit. Anything else in the driveway you can test that box on? If you get the same results, it's the box. Assuming box is wired EXACTLY as instructed? Digital stuff is pretty sensitive to things like ground differentials and voltage drops/spikes etc. I've seen it on a 6AL where somebody wired the main 12v source to the closest available instead of directly to the battery like the instructions dictated. It would NOT fire. Hooked + & - direct to the battery, vrooom! Kevin
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Re: Lash in the distributor drive
[Re: Twostick]
#3047147
06/01/22 04:46 PM
06/01/22 04:46 PM
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Joined: Jan 2003
Posts: 3,031 Erda, UT
67Charger
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OP
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Joined: Jan 2003
Posts: 3,031
Erda, UT
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Only other thing I have handy right now is my '81 F100 with the ole 300 straight 6. It's a Duraspark 2 ignition, so the wring would be a little diffferent, but it may still show wonky. Worth a shot.
As far as wiring the power source goes, the Digital 6 is currently tied to the 2/0 12V+ cable coming from the trunk from the battery cutoff at the under-dash starter solenoid (1st stop, and hub for 12V distribution). Ground is to the 2/0 12V- cable common Ground stud also near the starter solenoid. Alternator charge cable (4 AWG) goes all the way back to the battery terminal in the trunk. Since the battery powers the fuse panels through the cutoff, the alt cannot keep the engine running after the kill is thrown.
Last edited by 67Charger; 06/01/22 05:04 PM.
11.33 @ 118.46 on motor 10.75 @ 125.35 w/ a little spray Now, high Speed Open Road Racing - Silver State Classic Challenge, Nevada Open Road Challenge, Big Bend Open Road Race Rocky Mountain Race Week 2020, 2022 2.0, Sick Week 2023
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Re: Lash in the distributor drive
[Re: 67Charger]
#3052153
06/21/22 10:40 AM
06/21/22 10:40 AM
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Joined: Jan 2003
Posts: 3,031 Erda, UT
67Charger
OP
master
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OP
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Joined: Jan 2003
Posts: 3,031
Erda, UT
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Found another source of movement... The housing itself has loosened internally so the upper half could shake and rotate. The pickup has actually left a mark on the reluctor from contact. I made a pencil line on the housing then rotated it to show how much it moved.
11.33 @ 118.46 on motor 10.75 @ 125.35 w/ a little spray Now, high Speed Open Road Racing - Silver State Classic Challenge, Nevada Open Road Challenge, Big Bend Open Road Race Rocky Mountain Race Week 2020, 2022 2.0, Sick Week 2023
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Re: Lash in the distributor drive
[Re: 67Charger]
#3052215
06/21/22 03:47 PM
06/21/22 03:47 PM
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Joined: May 2019
Posts: 5,652 nowhere
Sniper
master
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master
Joined: May 2019
Posts: 5,652
nowhere
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Only other thing I have handy right now is my '81 F100 with the ole 300 straight 6. It's a Duraspark 2 ignition, so the wring would be a little diffferent, but it may still show wonky. Worth a shot.
As far as wiring the power source goes, the Digital 6 is currently tied to the 2/0 12V+ cable coming from the trunk from the battery cutoff at the under-dash starter solenoid (1st stop, and hub for 12V distribution). Ground is to the 2/0 12V- cable common Ground stud also near the starter solenoid. Alternator charge cable (4 AWG) goes all the way back to the battery terminal in the trunk. Since the battery powers the fuse panels through the cutoff, the alt cannot keep the engine running after the kill is thrown. Those cables are great antenna for picking up any stray EMI out there. If you have on O'scope or access to one it'd be interesting to see what kind of noise is on your power and ground feeds to the ECU. Also the feed from the pickup inside the distributor. What type of plug wires are you running? Solid core are great radiators of EMI. Which may be why the 36-1 wheel cured the issue, far enough away from the noise source. Computers don't know what to do with noise being fed into it. One simple way to cancel out noise is to use a twisted pair of wires.
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Re: Lash in the distributor drive
[Re: Sniper]
#3052237
06/21/22 07:12 PM
06/21/22 07:12 PM
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Joined: Jan 2005
Posts: 2,538 Milwaukee WI
TRENDZ
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master
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Milwaukee WI
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Doesn’t Edelbrock use “EFI Technologies” ECU? If they still do, you can unlock it and use any trigger system you want, including the previous 36-1 you were using. I would never suggest using a distributor to supply a signal to your efi.
"use it 'till it breaks, replace as needed"
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