Need help: backfiring, black sooty #3 intake port (pic)

[David Jones]

You can run it without the fan for longer than you think as long as there is no great load. On the F Vee we used ram air cooling but it was not unusual to run the engine for 5 to 10 minutes. Start up in the pits then drive to the grid which can be a quite a distance at some tracks. I used to run the engine until the oil temp moved off the stops at about 140*F on the grid so after the pace lap the engine was warm. If it was below 50*F which happened more than a few times it ran for considerably longer.