Lapping Valves

I’m actually going to have a full-on 3-angle valve job done on this head next week. More on 3-angle valve jobs later…

Regardless, I wanted to show the basics of lapping valves.
Figured it’d be good to show a general overview.

I made a quick video. I’m sick today… Hear me sniffling?


This ring below is the valve seat.

You can see below, the valve sits in the combustion chamber and needs to sit as closely / tightly as possible to the ring on the combustion chamber. Over time I guess the seat gets worn and can start leaking which causes lower compression and a weaker engine.

Another view below to see how the angle of the valve sits on the angle of the ring in the combustion chamber. This is really what is happening. You want the angle of the valve to perfectly match the angle of the ring in the combustion chamber.

This is the grinding material and lap tool.

See how the suction cup thing holds the valve.

2 responses to “Lapping Valves”

  1. Chris francione says:

    Ed, you can lap my valves anytime!

  2. Chris says:

    Thanks for the video, this makes it seem easier than I thought.

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