Diesel Engine Compression Tester

Craig Kruse · Feb 22, 2013

I need to check my compression on my 3400. Anyone have a recommendtion for an inexpensive testor :?: I won't have a lot of use for it other than to check my engine out so I don't want to spend mega bucks for one. I was considering the Harbor Freight $24 special but don't know if it will fit the injector holes or not. Any recommendations would be appreciated.
thanks

Paul in MN · Feb 22, 2013

I made my own. I got a junk Ford type injector from my diesel pump shop and gutted it out. It is best to keep as much of the bottom end of the injector as possible, as any missing metal gives a false lower compression #. You need a pathway for free air flow, and a Schrader valve to allow the compression air to go to the gauge, but not back into the cylinder. I put the Schrader valve at the top of the injector (fine thread) and welded a air hose male end to the injector body. Look for a gauge with max pressure of 500 psi, fit it with small diam (1/4" max) hydraulic hose joined to an airline female disconnect.

Depending on the engine model (NA or Turbo) you can expect 400+ psi from a NA and about 375 psi from a turbo engine. My 401 6 cylinder engines still give these numbers with over 10,000 hours on them. When testing the engine, take out all the injectors so it cranks over very easy, and leave the fuel shut off cable in the "off" position.

Sorry, don't know how to post pictures.

Paul in MN

Craig Kruse · Feb 23, 2013

Thanks Paul, I was hoping to be able to purchase one but your solution sounds better if I can get an old injector someplace and have someone weld the thing up like you suggest. It would at least be an exact fit for the engine.

Thanks again

Paul in MN · Feb 23, 2013

Craig,

E-mail is open on Classic. Send me an e-mail telling me where you are located. If you aren't too far away, you can borrow mine.

Paul in MN

Craig Kruse · Feb 24, 2013

(quoted from post at 03:28:28 02/24/13) Craig,

E-mail is open on Classic. Send me an e-mail telling me where you are located. If you aren't too far away, you can borrow mine.

Paul in MN

thanks Paul, not sure about the email option thing. I'm in modern view? Anyway thanks for the offer but I'm a few blocks south of you. I'm in south central Florida!!!! I need to get one anyway if I'm going to keep fooling with these old tractors or I can pass it along to my son who works heavy equipment as he doesn't have his own yet. Again thanks for the offer.

Diesel Engine Compression Tester

Craig Kruse

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Paul in MN

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Craig Kruse

Member

Paul in MN

Well-known Member

Craig Kruse

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