Lapping Valves…

The weather sucked this weekend, but at least we did not get any snow. I did make some progress on the EVO motor. Got the heads cleaned up, as clean as I could get them, and the valves lapped.

I watched a lot of videos on the process of lapping valves. This was one of the most helpful. The sounds, for determining when a valve has been properly lapped, were extremely helpful. So if you are looking to do this, this is a great how-to resource.

For the valve job I needed a lapping tool and lapping compound. I picked up these on Amazon, but the local auto parts store also had these on the shelf.

Oiled the valve steam, connected the suction cup on the lapping tool to the valve, applied the lapping compound around the edge of the valve, and inserted the valve into the valve guide.

The lapping tool is spun between the palms of your hand to grind the valve and valve seat.

This requires a fair bit of patience. Like in the video above, the lapping tool suction cup kept detaching from the valve. Keep the valve face and the suction cup as clean as possible and apply consistent pressure when spinning the tool to reduce this. As I worked through the valves I got better at it, just took practice and patience.

Lapped the exhaust valve and then the intake valve. In the picture below you can see the dull gray area around the exhaust valve.

The front head valves are lapped and seated.

Repeated the process for the valves on the rear head.

Going to clean things up again really good, just to make sure there is not any left over valve lapping compound on the valves and heads. I’ll get the valve oil seals installed and the cylinder heads assembled next weekend.

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