To use the Goodson Trego Electric Vacuum Tester (VT-KIT), plug it into a standard 115V outlet, select a matching vacuum plate, coat the plate edge with lube, press it over the combustion chamber, and turn the unit on to check if it draws and holds a strong vacuum. This tool allows you to instantly diagnose a poor valve-to-seat seal right on the workbench without any special setup or shop air.
A complete step-by-step breakdown of how to prepare, test, and troubleshoot using the device follows below.
1. Preparation and Assembly
- Assemble the Cylinder Head: Ensure the cylinder head is fully assembled with valves, springs, retainers, keepers, and spark plugs installed.
- Connect the Lines: Attach the vacuum tube complete with its inline filter and connectors to the electric piston pump unit.
- Select the Test Plate: Choose one of the 6 included vacuum plates that best fits the size and shape of the combustion chamber or port you are testing. Attach it to the quick coupler.
- Apply Plate Lube: Smear a thin layer of the included plate gel lube onto the non-porous foam edge of the plate. This prevents grease/oil from drying out the foam and guarantees an airtight seal against the metal workpiece.
2. Performing the Vacuum Test
- Position the Plate: Place the lubricated vacuum test plate firmly over the combustion chamber or valve port you want to test.
- Power the Unit: Plug into a 115V outlet and flip the power switch to turn on the electric vacuum pump.
- Close the Valve: If your model utilizes an inline ball valve, close it to isolate the vacuum pull.
- Read the Gauge: Watch the gauge needle rise. The unit is capable of generating up to 850 Mbar (roughly 12.3 PSI or 25 inches of mercury) of vacuum.
- Evaluate the Seal: If the valve-to-seat mate is perfect, the gauge will rapidly hit maximum vacuum and hold steady. If the needle struggles to climb or leaks down fast, air is bypassing a component.
3. Releasing and Locating Leaks
- Release the Vacuum: Open the ball valve or press the vacuum release valve depending on your specific kit configuration. Do not try to forcefully wiggle or pry the suction plate off the workpiece while under vacuum.
- Pinpoint Leaks (The Bubble Test): If a chamber fails the test, remove the plate and lightly spray the valves, valve seats, and spark plug area with a spray bottle filled with a bubble or leak-detection solution. Re-apply the vacuum plate and run the pump for a few seconds. When you release it and lift the plate, look for where bubbles have formed to find the exact leak path.