The it in this case is everything.
I went to work on the Spitfire today and to adjust the valves or points usually turn the engine over using the bolt on the harmonic balancer. I have a waterpump wrench I use to turn it
Wrench in action
Went to turn it and the wrench wasn't grabbing anything! A closer look reveals the bolt holding the balancer is missing.
It's a standard right hand thread and I turn the engine clockwise so somehow it loosened on it's own and fell off at some point.
Luckily I was ordering some parts anyway and the bolt is available although not cheap at $35 (a new OEM fuel pump was 39 for comparison).
Lesson learned driving a Brit car you have to learn to dodge the falling parts. Still, this car is a hoot and I wouldn't sell it for twice what I paid.