I spent a lot of time today working on firewall penetrations. I really wanted to find a spot for the fuel line bulkhead fitting however for the life of me I couldn't see on any drawing where to drill the hole for a fuel injected engine. I resorted to asking for help on the Vans Aircraft Builders facebook site and was eventually rewarded when US builder Bill Repucci told me about the "option" drawings. I went back home and checked on my Vans CD, and eureka!.... I felt like I'd struck gold. All the info I was looking for was contained right there.
Armed with a whole set of new drawings (albeit in A4) I could then start on the fuel line penetration. I made up the required doubler plate and match drilled to the firewall, before then alodining and priming ready to rivet into place tomorrow.
In amongst all this I also cut the 2" hole for the cabin heat valve, which was certainly easier said than done. I managed to drill the hole out to 1-3/8" with my stepped reamer, however after that the bit just wanted to tear into the stainless, rather than drill. I could envisage a mangled firewall so I enlarged the hole with a die grinder bit instead. The first picture below shows mid way into cutting the hole. It looks a mess in the picture, but it ended up okay.
It looks ghastly here, but I ended up creating a relatively neat 2" hole
Match drilling the doubler plate for the bulkhead fuel fitting
