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</o:shapelayout></xml><![endif]--></head><body lang=EN-US link="#0563C1" vlink="#954F72" style='word-wrap:break-word'><div class=WordSection1><div><p class=MsoNormal>For those of you who have tractors with 7/8” 18 TPI spark plugs and would like to do a compression test with the low cost compression testers kits sold today you are SOL. All the threaded as well as rubber stopper adapters are too small. The biggest is 18MM. 7/8” is equivalent to just over 22mm. Doing a compression test is impossible on a hand start tractor with that set up unless you can buy an adapter from 7/8” to one of the metric adapters in the compression tester kit. I just found a company Billman Company that sells a few of those adapters of various sizes including one from 7/8” to 14 mm. <o:p></o:p></p><p class=MsoNormal>https://brillman.com/?s=spark+plug+adapter&post_type=product<o:p></o:p></p><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal>I was thinking I was going to have to make one out of the compression kit rubber stopper adapter and braze it into the inside of a gutted sparkplug. This is a better solution in my mind. When I receive this I will be able to test the compression on my Hand start 1935 JD B. Will be able to compare cylinders by hand cranking, using a belt on the pulley or pulling it in gear. My current guess is the compression on cylinder # 2 is about half of #1 by the feel on the flywheel. We will soon find out. <o:p></o:p></p><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal>I also want to make sure that the manifold isn’t rusted out or leaking from the intake side to the exhaust side. So I made an adapter plate that fists on the carburetor intake side of the manifold and then drilled and tapped a ¼” Pipe thread and installed a quick connect air fitting. With the adapter plate bolted to the carburetor inlet to the manifold I can add air pressure to the intake side of the manifold. If things were perfect I should get no air leakage into the exhaust side but the intake valves may open slightly and allow air pressure into the combustion chamber. With the flywheel at TDC on #! Cylinder all the valves should be closed. If I get a bunch of air pressure into the exhaust I know I have a manifold problem. If that passes then if the intake valves open and I get no leakage out of the exhaust side than I know I have a good manifold and two good exhaust valves. If I get some leakage out the exhaust then I probably have exhaust valve problems. <o:p></o:p></p><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal>Have to get the B out of winter storage here and start doing these tests. I brought 4 restored DLTX-10 Carburetors and 4 Magneto’s along so I can isolate if either one of those are causing me problems. I hope I don’t have to pull the head on this tractor but my gut tells me that will be what happens as a result of the tests. Pulling manifolds on one of these old tractors is an exercise that usually ends up with 4 broken off studs in the head. Broken off bolts don’t scare me like they used to but it takes a whole bunch of time and frustration to get everything cleaned up again ready for new studs. . Maybe for once I will get lucky and not have to do major surgery. <o:p></o:p></p><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal>Dean VP<o:p></o:p></p><p class=MsoNormal>Apache Junction, AZ<o:p></o:p></p></div></div></body></html>