8-71 engine compression tester

[luvrbus]

Larry,don't forget and take a old fuel jumper line to make a bypass line so when you start the engine fuel it doesn't spray everywhere . 

[Larry B]

I made a jumper for fuel lines . I need to question a few other things. Used old whole injector. Removed all internal and seal welded all open holes. Top hole (where spring was) welded a 3/8" pipe nipple. All I have left in head is three push rods sticking up and valve springs on test hole. Plugged rocker arm mount holes with short bolt to stop oil flow. Installed test unit with hose and gauge. When engine was started I expected it to run rougher than it did. 15 seconds after starting engine the test unit started to smoke. I was NOT expecting this smoking. Glanced at gauge and shut engine down.Is it normal for the compression tester to get so hot that when oil lands on it, the oil will smoke light blue? First glance at gauge was 200psi. I might have too large and too long a hose between test unit and gauge. A lot of my compression is used to fill hose. I am going to mount direct on top of test unit. Should I expect gauge to bounce a lot? I do have a check valve I could add between test unit and gauge. Gauge is 600psi liquid filled. Hose was 3ft. long- 1/2" i.d.   

[luvrbus]

Reinstall the rocker stands the exhaust valves have to be in the loop and operational only the injector is out of the loop and it will bounce around , the gauge should be a direct mount with no hose only a bleeder valve which is not necessary IMO

good luck

[Utahclaimjumper]

Artvonne,, you are correct on the 80 pound pressure being an arbitrary number,, the regs state that a cylinder cannot loose more than 25 percent of what is applied. With the exception of the large bore Continentals, which now use a "calibrated orifice" method of testing. ( SB 03-3).>>>Dan ( 32 year I/A and counting)

[Larry B]

Did the test over the last two days. The home built tester from an injector seems to work only I don't like what it is telling me. I have a problem on both sides. Only 225 to 240 lb. compression. I ordered a tester today off ebay. Should have done what Brian suggested to start with. Was not expecting boths sides to read bad. An odd thing was I got a little higher reading at 600rpm than I did at 900 rpm. I believe I got pictures figured out will try and send one of tester.

[luvrbus]

Check the manual 600 rpm maybe right for a 8v71 n/a 

good luck