3 Angle Valve Grinding
Air cooled VW heads come from the Brazilian factory with single angle (45 deg.) valve jobs. This is adequate for a stock 1600cc motor, but will limit the flow if you're planning to add to engine displacement or use larger dual carbs. Since I had performed some smoothing around the valves with rotary tools, I knew I was going to need to have the valves re-ground. There was no better time to up-grade to a performance 3 angle valve grind.
This type of job is NOT recommended for the home mechanic unless you are educated in the proper techniques and own the proper tooling for the job. Below is a series of photos (all photos courtesy of the Robert Bentley Official service manual) illustrating the three angles that are cut in the steel valve seat:
By cutting the two extra angles in the seat, the air path is smoothed and flow is improved. This cost me $20 per head at the local machine shop. Well worth the money!
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Revised: August 29, 2003
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