[Gunter]

Originally Posted by Brotok

What is the proper procedure to break-in a rebuilt engine with a valve job?

I just rebuilt my '79 911 SC's motor, I ground the seats and valves as part of the job, replaced all bearings, rings etc. I'd like to know what the experts here recommend for the break-in procedure and I'd appreciate comments on the following:

1. When should I change the oil?

After 1-300 Miles plus new filter

2. When should I re-adjust the valve clearance? After a valve job, Porsche recommends adjusting the valves to 0.25mm, running the motor for 30 minutes and then re-adjusting the timing. I set the clearance to 0.25 mm but feel that 30 minutes is not enough time and plan to log about 1000 miles on the engine before re-setting the clearance to 0.1 mm.

Would love to see more info on the recommendation for 0.25mm and re-adjusting the timing? Ignition timing?

3. How should the car be driven during break in?

No high-revving past 4k. Did you rev up and down during the 30 minute ring-seating procedure?

4. When can I feel free to let her out?

After about 1k Miles

By the way, the engine runs fantastic - a lot more power, response, better sound, etc. This board has been tremendously helpful in the process, I am truly grateful for all your help.

Thank you.

1000 Miles with 0.25mm Valve clearance? Is that reliable info from Porsche?
Surprised you didn't get Wayne's book; a fantastic help for a rebuild.