Review on CTA Tools 98141 Pro Thread Tapered by Rene Putman

Worked well in an aluminum block for a tractor (Kohler K321). The tapered seat is good quality and I love that THIS guy doesn't have a lip sticking out of the block. Instead, you can insert the entire seat into the block and then, once you're flush, tap in with the tool provided to expand the seat's sidewalls into the block. This allows the spark plug to be placed in the block exactly the same distance from the valves as before (I have a flathead engine). Just make sure you: a) attach the block to something perfectly flat; b) Follow the instructions and first drill a hole for the spark plug (I ordered a Bosch CO2159 1/2"x 6" cobalt drill) on the press drill. First make sure it's perfectly vertical. c) Insert a thread cutting tool. Then start over with your fingers. Take some Tap Magic tapping fluid. Get the tap to bite into the block and be perfectly straight. d) Then use the long handled socket wrench to very CAREFULLY, SLOWLY and SMOOTHLY thread the faucet into the block. I used the Knock Magic every few turns to lubricate them. e) Remove any remaining metal shavings. Clean with spray lubricant and a rag. e) Install the seat by screwing in with your fingers and then tapping in with the tool provided. This will prevent the seat from being removed when the spark plug is removed. The seat must remain in place. It suited me perfectly. Just take your time, be patient. I spent several hours making mine.