DIY Timing Pointer to Confirm Timing on your LS Engine

Discussion in 'High Tech Retrofits' started by CasperCasper, Nov 3, 2019.

  1. CasperCasper

    CasperCasper Veteran Member

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    Hey guys,

    Here's a quick and cheap method for finding TDC and making a timing pointer for your LS Engine.

    Video here, Pictures and description below:

    www.youtube.com/watch?v=pZ6vMwiVHMo&


    Required:

    Timing Pointer - I used the Spectre 4237 ($5.26 CAD)

    https://www.summitracing.com/parts/spe-4237

    TDC Indicator - I used the Innovative 7880 ($30.04 CAD)

    https://www.summitracing.com/parts/ipa-7880


    How to:

    Begin by mounting the timing pointer. I used a stud in the timing cover with a coupling nut to attached the pointer. I orginally intended to use this pointer once and then take it off the engine as soon as I confirmed my timing. Procrastination got the best of me and I kept it on the car all year for thousands of miles and surprisingly it didn't move! If you see my marks there you'll see I mark the outside of the pointer (to ensure it doesnt move) as well as the timing marks. If they all line up then it hasn't moved.

    1.jpg

    2.jpg
    Heres the TDC Indicator I used. All it does is thread into the cylinder 1 spark plug hole and as the piston reaches TDC the indicator moves. When the indicator is at it's maximum extension you know you've got TDC. It takes a bit of time and playing around to ensure you've got TDC but make sure you get it right as this is the most critical part. If you were really crazy about it you could just keep using calipers on the indicator to ensure that the measurement is at a maxmium.Once you find TDC all you've got to do is scribe the marks!

    3.jpg


    I was also curious on the accuracy of this method and think that for most people this can be done to within 1 degree of accuracy. Based on the circumference of the balancer every degree is just over 1.6mm of circumference. I think it's fairly straightforward to get your marks within 1.6mm.

    5.jpg

    I hope this helps some of you out. This is just a simple tool for confirming your timing and not an extremely accurate one, but for most of us it should suffice and will definately help you get in the ballpark!
     
  2. badazz81z28

    badazz81z28 Veteran Member

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    Great info, but why? You can’t manually change the timing.
     
  3. CasperCasper

    CasperCasper Veteran Member

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    It's to confirm your timing, I should have made that more clear. Your commanded timing is not your actual timing. Put 10deg in your computer and it doesnt mean your engine is actually doing 10deg. In fact A LOT of forces induction engines blow up from thinking they have less timing or erratic timing. You may even be fine at 10 and then when it gets to 15 be giving the engine 20. It happens way more often than one may think
     
  4. wildkarde

    wildkarde New Member

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    But the scanner can tell you your actual timing a lot more acurately than that set up.
     
  5. badazz81z28

    badazz81z28 Veteran Member

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    A crank position sensor...a cam timing position sensor, I just don’t see how that can’t be the absolute accurate method. How much can commanded timing and accurate timing be off? I’m naive I guess but I just don’t see the computer being wrong. I honestly think your pointer would be the inaccurate one. You have to know exact TDC and align the pointer correctly and correctly have the diameter of the balancer right. Sounds risky to an engine unless your absolutely certain.
     
  6. 1980RS

    1980RS Veteran Member

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    I do know that on GM cars and trucks that there is variation in the reluctor wheel on distributor less engines that's why we had to do a crankshaft variation relearn all the time after messing with computer upgrades. I also think any timing you can put in via a computer could be skewed, does it happen? sure it does, look at the timing light issue with MSD boxes. His testing method does not lie, same as any other mechanical timing test. Good info and video.
     
  7. wildkarde

    wildkarde New Member

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    Crank relearn is all about misfire detection, its about adjusting for small variations in sensor head location and the like. It won't do anything for a reluctor wheel thats miss-installed. If your reluctor wheel is off far enough you would be able to detect it with this setup you have way bigger problems.
     

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