AFR misleading? Plugs tell a better story?

Fuel and Air Systems

  1. skidmark

    skidmark Well-Known Member

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    On number 3, I checked the plug wire by itself, also then connected to the cap, testing through terminal to spark plug wire end. All seemed good. Going to take a better look at cap inside when I get home. Only focused on #3 will take a second look to see how other terminals look.
    Rotor tip is amazingly clean.
     
  2. yellow rose

    yellow rose Doctor of Thinkology.

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    I've seen a rotor fail like that before. I'm not sure what goes sideways first...the screw/rivet gets loose or the slot the tip sits in allows the tip to move around and starts working on the screw/rivet and then they come loose.

    Either way, I've seen it before and it's happened to me and caught me off guard. Usually you see it with higher RPM situations, but in this day and age, junk is junk.

    Good catch.
     
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    • TT5.9mag

      TT5.9mag Two atmospheres are better than one

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      My guess is the plug fouled or something else caused resistance and the rotor tip heats up trying to arc across to the cap. Once the rivet heats up, the plastic loosesns up on it. Just a guess but yellow rose is right junk is junk. Just replace it with good quality and move on.
       
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      • mderoy340

        mderoy340 Well-Known Member

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        A small screw and a drop of epoxy will fix the rotor.
         
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        • TT5.9mag

          TT5.9mag Two atmospheres are better than one

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          Sure if you’re in the middle of the desert trying to get home or tying to make the next round without parts, but if you’re in your driveway diagnosing problems trying to eliminate variables I can’t see why you would.
           
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          • mderoy340

            mderoy340 Well-Known Member

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            Because the new crap part you replace it with can loosen as well. I've had Standard, Blue Streak brass rotors loosen in the past and the screw/epoxy works.
             
          • TT5.9mag

            TT5.9mag Two atmospheres are better than one

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            So don’t replace it with a crap part.
             
          • AndyF

            AndyF Well-Known Member

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          • skidmark

            skidmark Well-Known Member

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            Haven’t seen anything going on.
            I have an in tank electric fuel pump with 3/8 supply and return loop, regulated PSI @ a little over 6 PSI. Monitored by in car fuel gauge with remote sensor at regulator.
             
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            • skidmark

              skidmark Well-Known Member

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              Some how I missed this. Would have been a good thing to try/check.


              Will check this out and see what it’s doing.
               
            • skidmark

              skidmark Well-Known Member

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              Disconnected brake booster hose from manifold, it’s now attached and capped to the rear of carb. Tried a handheld vacuum pump to test brake booster, couldn’t get it to pump up. Not sure if pump is too small. So for now I’ll leave the brake booster capped and disconnected from engine. Thinking it’s bad maybe I’ll go manual master cylinder.
              Every time I think I’m going to work on it something comes up. Borrowed a leak tester so hopefully I can do it soon.
              Added a valve at inlet to ease up on pressure. Thanks for the info.

              23000828-82C5-4790-BC32-30A70FF309AE.jpeg
               
              Last edited: Feb 17, 2020
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              • AJ/FormS

                AJ/FormS 68 B'cuda fb, Form S clone ... 367/A833/3.55s

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                Yeah, that valve will soften the hit, and if you have the piston exactly at TDC-compression, hopefully the piston will stay there. You only have a 2 or 3 degree window, before 80psi ( my test pressure) will push the piston down.
                You can use less pressure, but it will be less accurate, because, remember your compression results. Furthermore, when the fuelcharge catches fire and expands,the pressure of those gasses in the chamber are gonna sky-rocket. IDK what the ratio is, and it varies continuously with rpm,throttle-opening, and air-density,etc but I imagine it could be many times the compression test numbers. I'll guess the pressure could, at some point, reach 400psi, I mean it's just a guess. So then my test pressure of 80psi is just 5% of that. and the typical tester calls for 30psi, which is less than 2%.
                If you just cannot get the crank to hold still, you can back off the rocker gear, and hook the tester up, which will push the piston to the bottom. This doesn't tell you anything about the condition of the top of the bore, or bad lifters, but it will still tell you about the valves and the rings.
                 
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                • skidmark

                  skidmark Well-Known Member

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                  I don’t know what happened, I did two rounds of leak testing today. Weird numbers on #1, and a couple of others. I was going to do a third and final test to confirm numbers. When warming up the motor I heard a tick at first I thought it was lifters which always seem to be noisy for a little while. Well it turned into a knock. I’m pretty sure it’s not an exhaust leak. Then I found a small puddle of oil on the floor. Looks like it was pushed out of dip stick. My brother in law has a very small wire camera he’s bringing over tomorrow to look in the cylinders. I’m thinking I should pull the pan. Ugh. Unbelievable. Motor was showing leakage from 3% to 16%
                   
                • yellow rose

                  yellow rose Doctor of Thinkology.

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                  3% isn't bad on a cold engine. Even a warm engine with that leak percentage isn't bad.

                  The 16% is not good. Where's the air going?? Could be head gaskets or something.
                   
                • skidmark

                  skidmark Well-Known Member

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                  Will do leak a test tomorrow. Pulled plugs #1 is black. Noise was from the front, was thinking water pump or alternator, but really don’t think they’re making this noise.
                   
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                  • 512Stroker

                    512Stroker We are all here because we are not all there.

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                    If your engine really did push out the dipstick and puke oil out you have an internal issue causing a massive amount of blowby (pressure) into the crankcase. This would be directly related to your leakage issue - Piston rings.
                     
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                    • AJ/FormS

                      AJ/FormS 68 B'cuda fb, Form S clone ... 367/A833/3.55s

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                      or a humongous scratch in the cylinder wall..
                       
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                      • skidmark

                        skidmark Well-Known Member

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                        Looked in #1 cylinder with wire camera, not the best quality.
                        Couldn’t manipulate it fully soft wire has a mind of its own. Of what I did see, nothing obviously wrong. Going to pull head off.
                         
                      • Idaho

                        Idaho FABO Gold Member FABO Gold Member

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                        :popcorn: hope its something easy
                         
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                        • Biomedtechguy

                          Biomedtechguy Active Member

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                          I am installing a 4 wheel, 6 piston calipers, complete Wilwood disc brakes system, including going to a Wilwood master cylinder.
                          I'm keeping my brakes MANUAL, and this new system is not a "budget" setup by any means. I'm keeping manual brakes because I prefer actually being able to modulate my brakes, rather than them being more like an on/off switch. I also know there are ways around having low vacuum and how that's bad for power brakes, but once again, the feel of manual brakes is my preference, and that's in a 70 Roadrunner, so more weight to stop than an A body.
                          Short version: unless you have leg weakness, I'd say don't hesitate to do manual brakes. More room under the hood too!
                           
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                          • skidmark

                            skidmark Well-Known Member

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                            Thanks for the info and good to hear. Going to give it a try. Either a 1” bore or 15/16” For master cylinder.
                            Aluminum Master Cylinder Part Numbers and Data
                             
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                            • skidmark

                              skidmark Well-Known Member

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                              Looks like the 1” listed in the link posted above is actually 1-1/32”, so I guess I’ll give the 15/16 or 24mm (same size) a try. Also will need to make an adapter plate and push rod for manual MC.
                               
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                              • Biomedtechguy

                                Biomedtechguy Active Member

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                                Here's the Wilwood master cylinder I have. 15/16" diameter piston bore. Quick Performance is the vendor.
                                950-261-13626-bk.jpg
                                The salesman I've been working with said that bore size master would work well with the slave cylinders in my setup, the calipers are unique in that they are SIX piston calipers on ALL 4 wheels. Anyway he said the combo would provide some good pedal travel, which is desirable to me, and allow for plenty enough force multiplication to lock up all 4 brakes should I press hard enough.
                                Wilwood 261-13626-BK: Aluminum Tandem Master Cylinder Kit Black E-Coat Finish | JEGS
                                 
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