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Tips For Starting Up A Rebuilt Engine With Sniper Efi

Discussion in 'Early CJ5 and CJ6 Tech' started by truckee4x4, Oct 9, 2021.

  1. Feb 14, 2022
    truckee4x4

    truckee4x4 Grant Kaye 2023 Sponsor 2022 Sponsor

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    You are totally right, I am!

    The limitation on tooth height is from the bottom of one of the bolt channels in the water pump above the balancer.

    I'm going to wire this up and grind down the teeth and get it ready to fire up this weekend. The best I can do for a storage scope is to borrow the oscilloscope from the Roundhouse (makerspace) and video it in 120fps with my phone.
     
  2. Feb 14, 2022
    truckee4x4

    truckee4x4 Grant Kaye 2023 Sponsor 2022 Sponsor

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    Here's an interesting update from one of the admins on the Holley forums about the Sniper potentially also being able to control timing:

    I'm NOT going to try this (one step at a time) but the idea is interesting nonetheless.
     
  3. Feb 14, 2022
    zinertia2

    zinertia2 "and which part are you keeping?" 2024 Sponsor 2023 Sponsor 2022 Sponsor

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    Grant
    Sorry was not clear - tooth longer is additional length around the circumference not height
    Dennis
     
  4. Feb 14, 2022
    truckee4x4

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    Gotcha - I will see if the current design works before I modify and have another final one cut. The current tooth circumferential length is 7/32”. FE8923A3-D25E-405D-A31B-6F15F669B22F.jpeg
     
  5. Feb 14, 2022
    truckee4x4

    truckee4x4 Grant Kaye 2023 Sponsor 2022 Sponsor

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    Got the sensor wheel prepped down to three teeth and installed (view from below):
    2282503D-E759-4DA8-AB9D-504C8E4CD740.jpeg
    Interestingly, once centered and bolted on, two teeth were 0.0040” from the sensor, and one was just about kissing it. Not quite sure how that is possible given the fact that everything is symmetrical in my CAD drawing, the wheel is centered, and the part was laser cut in steel…?

    So, pursuant to @Norcal69 s directions, out came the file and now all three teeth are around a little bit more than 40 thou when we spun the engine around by hand.
     
    Last edited: Feb 14, 2022
  6. Feb 15, 2022
    truckee4x4

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    Per some feedback on the Holley forums, I think I might need to modify or make another sensor mount bracket that moves the sensor out a bit - the inside jam nut is too close to the end of the sensor tip. I was planning on making a thicker one anyway to cut down on flexibility/vibration - the 0.125" 5051 flexes too much. If I made a thicker one I could drill or machine out a pocket in it for the jam nut that moves it outwards.

    It has also been suggested that at 0.135" thick the trigger wheel may be too small for a sufficient magnetic field to be generated as the tooth passes the sensor....so that may need to be modified as well.
    UNADJUSTEDNONRAW_thumb_8a64.jpg

    As far as testing this before I made new parts, I was planning to connect the HEI tach output back to the Sniper coil (-) and crank the engine over with the fuel pump relay pulled, and with a scope attached to the sensor wire output, to see if it is working at all as-is. MIght borrow the Scope from the Roundhouse and try that tonight.
     
    Last edited: Feb 15, 2022
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  7. Feb 15, 2022
    timgr

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    Last edited: Feb 15, 2022
  8. Feb 15, 2022
    truckee4x4

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    Last edited: Feb 15, 2022
  9. Feb 15, 2022
    zinertia2

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  10. Feb 15, 2022
    truckee4x4

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    That’s a pretty cool looking gadget Dennis thanks for sharing.

    While the “restrooms this way” sign I’ve been lasering for work was drying, I made a new Wooden prototype version of the trigger wheel, and bolted on at lunch.

    3126DC0B-AA95-476A-BAAF-0635FED5B17F.jpeg
    E954A7BD-48FC-4481-A9E4-6B4471F87D41.jpeg

    I think this is going to work much better than what I had before, it is quarter inch thick and I made the three teeth 11 mm long which is the diameter of the sensor. I also made the center hole of the disc slightly larger to allow for motion of the balancer.

    Next I need to redesign the sensor mount bracket to move the sensor about a 16th of an inch towards the front of the vehicle to account for the increased thickness of the wheel, and then I’m going to manufacture another copy of the shape of the fuel pump block off plate to act as a spacer underneath to move the center mount bracket out.
     
    Last edited: Feb 15, 2022
  11. Feb 15, 2022
    supertrooper

    supertrooper Member

    moreno valley, ca
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    Once you find the correct height for the sensor you could remake the bracket out of thicker material and have a tapped hole for the sensor so only one jam nut is needed on the back.
     
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  12. Feb 23, 2022
    truckee4x4

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    Got the (hopefully) final parts in. Everything looks good; I do wonder about the weight of the trigger wheel when cut from 0.25" mild steel.

    Mounting Bracket:
    UNADJUSTEDNONRAW_thumb_8acf.jpg

    Bracket and spacer plate:
    UNADJUSTEDNONRAW_thumb_8ad4.jpg
    Everything but the sensor attached. When attached there is plenty of room for sensor adjustment on the backside.
    UNADJUSTEDNONRAW_thumb_8ad3.jpg

    Regarding the weight of everything. The 0.13" thick steel prototype crank trigger wheel and three attaching Ti bolts are 12.87 oz, and the 0.25" wheel is 2x that weight at 21 oz. For comparison, I weighed the water pump pulley and spacer and bolts they are about 28 oz. Do you guys think the extra ~22 oz on the end of the harmonic balancer will adversely affect the crankshaft or engine performance, or is that weight negligible?

    Also, second question. I was pondering the sensor wiring, and wondering if the green wire from the twisted green/violet pair would work as a "clean ECU ground" instead of the way I have it wired up, which is a 18ga wire with a 45V/15A Schottky diode that goes to the battery (-).

    We already established that the (B) white wire from the sensor goes to the (B) violet wire in the Sniper Harness (Crank signal +), with CD Box ignition type set on the touchscreen. What I am wondering is - could I make use of the dark green "Crank Signal Negative" wire in the Holley harness that is described as "Engine Speed Signal Ground?" for the Hall effect sensor ground or am I better off going to the battery? I ran this by an EFI expert and he said yes, butt I am wondering what you guys think? I'm willing to give it a go this weekend, if it's not snowy and I can have the garage door up. Still can't drive without good brakes (or seats) but could turn the engine over and generate a Datalog for a closer look.
     
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  13. Feb 23, 2022
    zinertia2

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    Just an opinion
    Think the 0.13 thick material with a “longer” width tooth would have weighed less and likely done as well as the thicker material.

    Best to spin the wheel with the sensor hooked up and look at the signal from your old design and new width design wheels to see if there was an issue to begin with, or the old design was sufficient.

    difficulty is getting to the rotational speed that you need which would be near the max to reduce the “dwell” time of the ferrous iron under the sensor.

    Reducing the old teeth in about half their length might also give you an idea about the reduced dwell time at a slower rotational speed.

    I don’t know what the minimum time is to “trigger” the sensor
    Dennis
     
    Last edited: Feb 23, 2022
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  14. Feb 23, 2022
    truckee4x4

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    Cheers for this Dennis. I'm going to try both wheels and see if there is a difference in sensor readout. Looking at the Holley generic trigger wheel, the teeth are fairly short in circumferential length (and hard to tell but that looks like 1/8" not 1/4":

    [​IMG]

    I think I should be able to pull the fuel pump relay and turn the engine over and get a reading for about 10 seconds or so, right?
     
  15. Feb 23, 2022
    zinertia2

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    Grant
    That should work for a low speed trial. You may not see any issue unless it running at a much faster speed.
    If that is a generic Holley wheel it looks like the original wheel could have had shorter length teeth and still work- likely no issue with the original. (Might ask Holley what the wheel width is as pictures can be deceiving- and if there is a minimum width trigger wheel for the sensor)
    Dennis
     
  16. Feb 23, 2022
    zinertia2

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    Grant
    If weight is an issue a second row of holes centered between the current holes and closer to the virtual center of the ring could save a few ounces.

    I am guessing “area” of the ferrous material as it passes the trigger is what counts.
    Next question is “instantaneous vs averaging area” as the sensor passes

    Better to just try it!!!


    From Holley site:
    Features:
    • 7.25” diameter, 1/4” thick, billet steel, 36-1 tooth, crank wheel with Black Zinc Oxide finish for superior corrosion resistance & striking good looks
    • Crank wheel centers off of the balancer’s hub, eliminating the need for a centering ring
    Dennis
     
    Last edited: Feb 23, 2022
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  17. Feb 23, 2022
    truckee4x4

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    Yeah I'm inclined to just try the thicker one since I have it and see how it goes.

    FWIW I asked my engine rebuilder for his opinion and this is what he said:

     
  18. Feb 23, 2022
    Jw60

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    I wouldn't worry about the weight. You can find a balance shop to balance the balancer assembly but they will need a crank to spin it. You won't notice it over the normal shaking due to the 90deg v6.
    Worst case scenario the part shifted while on the laser and the holes aren't concentric to the profile, if so you will notice while setting sensor gap. I don't see any chance in that being off balance enough to matter. (I even doubt a clutch disk is perfectly balanced)
     
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  19. Feb 23, 2022
    truckee4x4

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    I have a question for other Sniper folks - what did you use for a throttle linkage from the accelerator pedal arm on the Engine side of the firewall to the Sniper?
     
  20. Feb 25, 2022
    truckee4x4

    truckee4x4 Grant Kaye 2023 Sponsor 2022 Sponsor

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    I made an alternative prototype of the trigger wheel for @zinertia2 (and anyone else) willing to put some spacers under the alternator and water pump and pulley:

    6D386746-DC17-4CE4-9542-0939163C8BD2.jpeg
    60B3F05B-6136-4FB4-AE14-544C824A92ED.jpeg E3AEA986-A2A8-463E-86D8-E5620C6BD760.jpeg
    Tested the fitment over the bolt holes and swaged bolts, and will adjust the sensor mount as well. Going to order this out of 0.104 mild steel and test it out.
     
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