Originally Posted by
Frank L
Heat cycle method
1. Heat engine to 220+ idle 10 mins
2. Let cool usually about an hour
3. Repeat 1&2 3-5x
4. Heat to 220+ and bump idle up to about 1/4 throttle. Let the rest of 1qt run through the engine on a hudy break in bench keeping the temp 200+ (heater and adjust hsn/ lsn) (Usually takes about 2 hrs)
5. Run another qt through in the car on the street with the head wrapped very rich keeping the temp 220+ continuously. (Takes about 1 hr)
6. Take to the track and tune to kill. Usually there's stil metal pinch so the idle needs to be a little higher than normal until that metal pinch is gone.
Why wait an hour between each heat cycle? Run a fan on the engine to cool it off, check the plug/head button/block temperature with your temp gun and fire it back up after the temp drops below 100 degrees. It only takes about 5-10 minutes between heat cycles. I've done it this way for years on many engines and it works fine.