Pro Flo 4 Timing

Electrical and Ignition

  1. Ivan Baez

    Ivan Baez 426 SB daily driver

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    hopefully you can test drive it soon. I will check what mine is doing at WOT to see if its adding vacuum timing while doing that if the sensor is reading incorrectly. Got a flat tire I have to fix tomorrow in order to drive it :S

    I think that since the ECU can play with the timing electronically there may be two ways to fix this.
     
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    • Mopar73340

      Mopar73340 Well-Known Member

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      So, Pulled my distributor cap off today since the MSD adjustable rotor arrived and found the following.

      7088673E-674E-42C4-A392-C6E3A789B7BE.jpeg

      E1C08A54-A3BD-4AA3-878C-9AEB2F59DDF0.jpeg

      BD46E406-1804-4CC7-8E3B-81E780478D9C.jpeg

      4E80A312-8935-467C-85D4-BC496094C284.jpeg

      First picture =0*
      Second =12*
      Third =30*
      Fourth =35*

      2B0D1C29-7408-4C75-A8CB-AF14CEDB8759.jpeg

      And the last one shows the rotor with about 1K miles on it. Obviously the spark has been predominantly using the left side.
       
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      • Ivan Baez

        Ivan Baez 426 SB daily driver

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      • TurboGLH

        TurboGLH Well-Known Member

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        Ok, drive report. Huge improvement everywhere. Cold start is much better, spins twice and idles right away, no throttle req as before. Warm and hot starts are even better, barely spins before it catches.

        Previously when cruising the car had a stumble with small throttle input and required extra throttle to clear up. That's all gone, drivability is vastly improved.
         
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        • Cal Tonsley

          Cal Tonsley Well-Known Member

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          Great to hear, thanks for the update!
           
        • Mopar73340

          Mopar73340 Well-Known Member

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          This is great to hear. I hope to try mine out tomorrow if it doesn’t rain. I also have the stumble on light throttle.
           
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          • Ivan Baez

            Ivan Baez 426 SB daily driver

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            it sound excellent, please share the screenshots of your timing settings in the edelbrock tuner application, as well as general engine specs to see what we are talking about.
             
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            • TurboGLH

              TurboGLH Well-Known Member

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              416ci, CNC SM heads, mechanical roller 242/242 @ .050, .571 lift.

              Also has 5 deg of vacuum advance.

              Screenshot_20210423-191812.jpg
               
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              • Cal Tonsley

                Cal Tonsley Well-Known Member

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                Thinking about this a little more, the SB Chev PF4 Distibutors that I’ve seen (and maybe others) do in fact use the replacement rotor that Edelbrock specify (see photo below) To me it looks like this rotor is broader than the SBM (OE Chev based) rotor, this may explain why this issue is Mopar specific.
                Anyway, we’re the lucky ones if we can buy an adjustable rotor and phase it’s position accurately!
                upload_2021-4-24_9-57-51.jpeg
                 
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                • Ivan Baez

                  Ivan Baez 426 SB daily driver

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                  thanks, that is good info. in my case:

                  426ci, 12.5:1 comp, ported Edelbrock performer heads with 2.08 intake valves, 1.6 ratio rockers, SB HYD RLR CAM 238/242 -110o LSA. run on 91 octane pump gas. 1150RPM idle. driven at 6500 ft above sea level.

                  Theses are the settings I have now, plus 5 degrees vacuum advance:

                  WhatsApp Image 2021-04-23 at 8.01.03 PM.jpeg
                   
                • Ivan Baez

                  Ivan Baez 426 SB daily driver

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                  Today I finally was able to drive the car, and saw some interesting behavior, similar to the one posted by a member on a video on this thread.

                  The vacuum readings are off, which confirmed what I suspected in why I had to pull the timing back so much to make sure the engine stays smooth at WOT all the times and avoid thos small hesitations I felt sometimes when getting close to the RPM limit.

                  When the engine was not running you can see it reading -5.9 of vacuum already. (see attached pic). At WOT the reading is around -7 inches of vacuum, so if I have -5 vacuum advance that is adding 1.2 degrees to my top RPM based advance. when I had that set at 34 or so it was really going to 35-36 or so. At cruising or when releasing the pedal with no load most of the time my vacuum reading is between 15-19 inches of vacuum.

                  Since gas quality here is not as good sometimes here and my compresion ratio is rather high (12.5:1) I will change the parameters in a way that at WOT I will have around 32 degrees total and plus 10 degrees more at -30 inches of vacuum.

                  For what I read in the edelbrock forums the vacuum advance is linear from 0-30 inches, so whatever max value you put in there will be applied linearly additively all the time the engine is running as long as you dont have 0 inches of vacuum, so be mindful of that when setting your parameters.

                  I hope the info helps.

                  WhatsApp Image 2021-04-27 at 9.51.42 AM.jpeg
                   
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                  • Ivan Baez

                    Ivan Baez 426 SB daily driver

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                    were you able to check the physical timing advance with a timing light vs what the edelbrock application says after you made the adjustement in the cap?. I wonder if the EFI computer will now think it has a different timing than the physical one.
                     
                  • BergmanAutoCraft

                    BergmanAutoCraft FABO Vendor FABO Vendor

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                    How is it you’re at 12.5:1 compression with 91 octane fuel?
                     
                    Last edited: Apr 27, 2021
                  • TurboGLH

                    TurboGLH Well-Known Member

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                    I didn't, but I can. I'm working on a header leak that I think is causing me to run super rich, but once I'm back together I'll check and report back.

                    I was able to set base timing with no issues, so I'm expecting the timing to be where it should be. The adjustable rotor doesn't move the trigger wheel inside the distributor, just where the rotor and post are in relation to each other when a plug is fired.
                     
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                    • Cal Tonsley

                      Cal Tonsley Well-Known Member

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                      I note that ‘Bite Me’ on the Edelbrock forum is now putting it down to timing chain slackness and the need to run a tensioner. I replied by stating that if that’s the case then phasing of the rotor should be no benefit.
                      I still suspect that the different, narrower rotor they use on SBM’s is really the culprit, I’ve asked why they choose to use this on SBM’s.
                       
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                      • BergmanAutoCraft

                        BergmanAutoCraft FABO Vendor FABO Vendor

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                        I don’t like that guy’s attitude... I have a tensioner....
                         
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                        • Cal Tonsley

                          Cal Tonsley Well-Known Member

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                          Thanks Ivan, good info!
                           
                        • Ivan Baez

                          Ivan Baez 426 SB daily driver

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                          Hi. I use aluminum heads and flat pistons paired with cometic 0.051 compressed thickness gasket. Also live at 6500 ft above sea level.

                          WhatsApp Image 2021-04-27 at 4.54.20 PM (1).jpeg

                          WhatsApp Image 2021-04-27 at 4.54.20 PM.jpeg
                           
                        • Ivan Baez

                          Ivan Baez 426 SB daily driver

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                          If I understand you right that would mean the rotor and the post will fire when they are aligned at the middle, rather than when they are getting apart, ensuring a more direct spark path?. If this is so it sounds like a basic design issue Edelbrock should have got right since the beggining.
                           
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                          • Ivan Baez

                            Ivan Baez 426 SB daily driver

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                            I have a timing chain tensioner already, that should not be the issue.

                            WhatsApp Image 2021-04-27 at 5.09.13 PM (1).jpeg

                            WhatsApp Image 2021-04-27 at 5.09.13 PM.jpeg
                             
                          • TurboGLH

                            TurboGLH Well-Known Member

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                            You got it spot on. It seems to be an issue specific to mopar small blocks, based on the replies on the Edelbrock forums. But, it seems to be fixed, so I'm happy to just move on and enjoy the car. Like the TPS I had to replace, not happy, but it's fixed now.
                             
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                            • BigBlockMopar

                              BigBlockMopar BigBlockMember

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                              Why are your pistons are installed upside down...?
                               
                            • Ivan Baez

                              Ivan Baez 426 SB daily driver

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                              They were just put there for the picture when the parts arrived but before engine assembly I guess, since I was following up remotely the engine build.

                              Here is a more recent pic of the actual assembly with the correct orientation.
                               
                              Last edited: Apr 27, 2021
                            • Ivan Baez

                              Ivan Baez 426 SB daily driver

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                              here

                              WhatsApp Image 2021-04-27 at 5.36.22 PM.jpeg
                               
                            • Mopar73340

                              Mopar73340 Well-Known Member

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                              I have not been able to drive mine but it starts easier and I can take it up to 4-5k rpm now with no miss or backfire. Before could not get past 3k rpm.

                              I also disagree with the chain tensioner theory as both of my engines did this the worst being the one with the tensioner in it.
                               
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