I made this leakdown tester off the top of my head at lowes using some other methods I found online. Works effectively and for twenty five dollars you cant beat it. I found all the materials I would need at Lowes so you shouldn't have any trouble at a local hardware store.

Materials:

Mini Air Pressure Regulator
Pressure Gauge 0-100psi (mine came with the regulator)
12" grease gun hose
1/4"-1/8" Reducer
Quick Disconnect Fittings
Teflon Tape
Spark Plug Adapter



Pretty straight forward on assembly. The only tricky part was finding a spark plug adapter, some say to knock off the porcelain off an old spark plug and drill the guts out. Fortunately for me I had an extra adapter from my compression tester. If your as lucky as me, I just used a center punch to knock out the air valve in the adapter and you now have a leakdown tester adapter.

Or you can buy a brand new one from Harbor Freight for $29.99. Harbor Freight Tools - Quality Tools at the Lowest Prices

haha I looked for ones and most were upwards of 75 dollars..good find.