The one I made is like this: Compressor with regulator, shrader male disconnect into tee with 200lb. guage,close nipple, ball valve, close nipple, tee with another guage, then a flexable line to a quick disconnect, and then a glow plug adapter. This is all 1/4" brass. The flexable line has 1/8" threads on each end, so one would need two 1/4"x1/8" bell reducers. With ball valve closed, air goes in and brings the first guage up to 100lbs. Ball valve is opened to let air into cylinder. Then ball valve is closed and guage is watched for drop. If anyone see's any flaws in this design, I would like to hear them? I hope this helps.