PC-100SLC Valve Spring Seat Pressure Tester - High Precision Automotive Tool for Engine Performance Testing (Red) - Perfect for Mechanics, DIY Enthusiasts & Engine Builders

This is an excellent tool. Although it appears that this tool is primarily a favorite for racers checking springs at the track, I wanted a tool to check actual seat pressures of my valves during an engine rebuild. After trusting the "experts" and head machine shop on spring selection and setup only to have a cam go flat in 20 minutes during the break in attempt, I ordered this tool to check the replacement springs I ordered myself before reassembly. The desired seat pressure for my application was 112 lbs. (old school solid flat tappet cam). The springs I ordered were rated at 135 lbs. at standard height and 111 lbs. with a +.060 keeper. Once installed each measured 110 - 112. Perfect, and piece of mind for reassembly. In the picture you can see the shims in the tester allowed for exact placement of the pressure wheel centered over the roller pin. A test of the prior springs that were supposed to be set at 155 lbs. showed an actual seat pressure of nearly 170 lbs. This would give about 400 over the nose, and is clearly why the cam / lifters did not live past break in. While it appears to be a bit of a religious argument that a bench style tester is required for setup, this is a hobby for me and I'm not going onto business. I wanted an actual reading of the springs as installed on the heads and this tool is perfect for my needs.