Hello all....I've been having an issue of the car having to crank for ages before starting...and whilst it's cranking I can hear a loud compression release (hiss) sound with each engine turnover. It's fuel related as if I crank the car with the ignition off and then after a minute of that turn the ignition on it runs straight away. I cleaned and rebuilt the carb yesterday and that did not help...still cranking for ages. But I noticed my car-rearward banjo bolt-with-a-hole is missing. I changed the head gasket in spring and I know it was there...but maybe I didn't torque it up and it vibrated its way out over time?...either way could this be responsible for the hiss cranking sound and the slow starting? What's the significance of the size of the hole in the bolt?..after all a missing banjo bolt is equal to just a larger hole right? Can someone help me understand the design of this banjo bolt? Thanks!

First of all it is not a banjo bolt it is a bolt with a hole through it. It is a safety device as if the head gasket blows the poison exhaust gases will escape through the hole rather than find their way into the cabin via the heater ducting. If you have hissing and gas escaping via the hole then you have a blown head gasket.

Thanks for the feedback and the PM. In response I did a couple of things... whipped off the carb and the rockers and tightened my head bolts to 41Nm...they were not under much torque...so lesson learned for me there. And I made my own (let's not call it a banjo) bolt with a hole down the middle.
Still takes a while to start...but I can live with that and hopefully so can my neighbours