Testing Oil Pressure with a Comp tester?

Small Block Mopar Engine

  1. seabee

    seabee FABO Gold Member FABO Gold Member

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    Hi Gang, hope everyone is doing well. Is it possible to test oil pressure with a compression tester gauge? I have tons of fittings and a 0-300 PSI comp gauge. I am repairing my gauge cluster and want to reference the stock gauge lines to numbers.

    Thanks

    -Billy
     
  2. dustinmoran91

    dustinmoran91 Well-Known Member

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    Im sure you could but it might ruin the gauge, its made for gases so the passages are small and getting the oil back out might be tough. I could be wrong though. But for all the trouble it would take you can buy those cheap oil pressure gauges at parts stores for $15ish dollars and then you can mount it in your dash and always know where your at lol
     
  3. TrailBeast

    TrailBeast AKA Mopars4us on Youtube

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    Theoretically, it should work.
    But you sure must be bored or need an oil pressure gauge pretty badly. :)
     
  4. seabee

    seabee FABO Gold Member FABO Gold Member

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    Thanks for the replies. I think you're both right (about getting the proper gauge and being bored).
     
  5. TrailBeast

    TrailBeast AKA Mopars4us on Youtube

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    I could totally picture doing that if I was bored.
    Once when I was bored I built a blower for my Briggs minibike and blew the head off of it. :)

    possibly ruining a comp tester aint so bad
     
  6. 67Dart273

    67Dart273 FABO Gold Member FABO Gold Member

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    Won't hurt a thing. What sort of gauge do you have? My favorite and the REASON I BOUGHT IT is an old Proto which uses the same (Hanson Milton) air connectors as my shop air. This means that I can buy fittings off the shelf to fit the gauge head. I use it for all kinds of stuff, including a home-made leak down tester, and by removing the valve core from the plug end, I use the hose/ ends with the leak down, as well as for injecting air for changing valves, etc.

    (Many newer gauges do not use standardized air fittings so I have no advice for ya there)

    Here's how mine is built, and I can buy these style quick connectors at Lowes:

    Used to be known as "Hanson Milton" or "Industrial Interchange" There are at least 6 types of "standard" 1/4" air fittings, which has become muddied in the past couple of decades. Sears or someone had the bright idea of coming up with yet another type years ago to gain "captive" customers, and of course the other air supply manufacturers had to follow suit

    [​IMG]
     

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  7. dustinmoran91

    dustinmoran91 Well-Known Member

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    But all the uses you listed are for air applications not oil. To let air out you just push the relief valve and its empty but how would you drain the oil?
    Also and i dont know if this makes sense but, since air compresses wouldnt the gauge be calibrated for air applications? Oil being a liquid is incompressible and might give a different reading?
     
  8. seabee

    seabee FABO Gold Member FABO Gold Member

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    It's a cheapo Actron. It has the same standard hose as yours and came with 6 different fittings, one of which is the exact fitting for the oil pressure sender. [​IMG]
     
  9. 67Dart273

    67Dart273 FABO Gold Member FABO Gold Member

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    Uh,,,,,,,,,,,,,,,no,,,,,,,,,,,,,,,,I said I use it "for all kinds of things" and gave those as examples. I HAVE in fact used it for oil pressure checking

    You have to realize that when doing a compression check on an "ill" engine, just about anything might find it's way INTO the gauge, including (for those brands that use auto trans modulators) ATF, engine oil, coolant, and gasoline, and probably ..............water.

    The only thing that is gonna hurt that gauge is something that is highly corrosive, or enough pressure to pin the gauge and damage the clockwork.:eek:ops:
     
  10. fishy68

    fishy68 Tyr Fryr's Inc.

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    The oil pressure switch looks like 1/8" pipe and pipe threads are taper seal. The test adapter is an O-ring seal and I'd be real surprised if the thread count per inch is the same but you might get lucky enough for it to work. Just be real careful screwing it in that you don't mess up the threads in the block.
     
  11. 67Dart273

    67Dart273 FABO Gold Member FABO Gold Member

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    No I would guess your last is a photo of a 10mm plug thread. These were used for a very few years in old Chivvy 6's (216s?) and Pontiac straight 8's at least.

    But with that gauge being one of the "lucky" ones with a standard series air fitting, it's no big deal to buy a matching coupler and simply bush it down to 1/4 or 1/8 pipe as required.

    I was amazed, back in my HVAC/R days, the first time I tore into a Lennox Pulse furnace, to find that a modified version of a 10mm plug was used as a flame sensor!!!

    (In fact the ignitor actually IS a spark plug)

    [​IMG]
     
  12. seabee

    seabee FABO Gold Member FABO Gold Member

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    Well, now I guess I have to try it for the sake of science.

    I have an entire Kennedy tool box that I bought that was filled with brass adapter fittings. I'm sure there is an 1/8" adapter in there somewhere.
     
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