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How To: DIY Pop Tester (without welding)

Discussion in 'IDI Tech Article' started by BDCarrillo, Feb 22, 2015.

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  1. BDCarrillo

    BDCarrillo Supporting Member Supporting Member

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    Jul 19, 2014
    Abilene TX
    Why a new thread on pop testers, when we have a good one by Oldbull in the tech section? Because I wanted to assemble one without welding, opening up possibilities for members who don't have/know a welder.

    Gauge (use 0-3000 psi)
    1/4 NPT to M12x1.5 metric adapter
    1/4 NPT F-M-F Tee
    1/4 NPT M-M nipple (can be upgraded to a check valve )
    Porto-Power or Harbor Freight manual hydraulic pump Use this 20% off coupon

    To adapt to an injector, you have two verified options:
    1x stock injector line ---OR--- a stock timing ferret adapter and 6mm tube, 2x 6mm tube sleeves, and 2x 6mm tube nuts
    Lowest rated part is 3,000 PSI.

    NOTE: The 6mm tube nuts will NOT seal directly to an injector. You must use a stock timing ferret adapter OR a stock hard line. Tube/nuts/sleeves NOT required if you use a stock injector line. To fit the tube into the timing ferret, drill out a small cavity for the tube sleeve to fit in, and slightly flare the end of the tube.

    POSSIBLE Workaround: Bubble flaring the 6mm tube on the injector side and leaving out the tube sleeve *may* work, but this has not been tested.

    Here it is:

    Tee fitting forms the heart of the gizmo. The metric adapter allows the use of either a stock line -OR- a 6mm line with tube/nuts/sleeves and a timing adapter.

    Why bother? A leaking injector I received from IDIoit dribbled at about 1000 psi... opened it up to find a sliver of metal. A cycle through an ultrasonic cleaner and with the original shim pack it popped cleanly at 2250 PSI (obviously will dial it down).

    Q: Couldn't I buy an actual tester for that much? Maybe, but then you wouldn't have a hydraulic porto-power type pump with accessories. They're pretty darn useful to have around. You might find a pump on Craigslist. There are a couple near me for $50.

    Q: Why not use a bottle jack? You can, if you can weld. 3/8 NPT Weldable adapter (1/4 NPT is too small to fit the top of a jack) and use a 3/8 NPT to 1/4 NPT nipple instead of the 1/4 M-M spec'd above. I built one using those parts and 2-ton Harbor Freight bottle jack. They (bottle jacks) suck at holding pressure.

    Q: Does this Harbor Freight pump hold pressure? Yep, it holds 1700 PSI for a good 5 minutes, and creeps down to 1500 indefinitely.

    Q: Can I use plumbing fittings? Absolutely NOT! Plumbing bits are rated to about 300 PSI for brass fittings. The minimum rating of the fittings I've spec'd ranges from a low of 3000 PSI to a high of 6000 PSI.

    Q: Why a 0-3000 PSI gauge? McMaster-Carr recommends using a gauge where your operating range is between ~25-75% of the max pressure of the gauge. With a 4-1/2" face and 100 PSI graduations, this gauge is very easy to estimate to the nearest 25 PSI. It's also inexpensive.

    Q: Where do I get shims, and how many do I use? I recovered a bunch of shims from junked injectors. A 0.001 shim will change the pressure by about 55 PSI. Use what you need to get a pop pressure of 1850 PSI, +/- 50.

    Q: What fluid do I use? Diesel, typically. I'm using WMO cut to 85/15 with RUG, filtered to 1 micron.

    Build at your own risk, use at your own risk, don't be dumb, etc etc. :backoff



    Last edited: Feb 22, 2015
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