I've finished the inspection port installation
on the fuel tank
and have attached some photos. I usually find when I do something new and I want it done perfectly, I usually have to practice first. Hopefully someone else can benefit from my experience.
As before, I started by cutting a backer ring and face plate. In this case some .125 aluminum plate I had access to that seemed about appropriate for the .090 tank. The backer ring was drilled and tapped for 1/4" x 20 aluminum bolts which were inserted from inside leaving studs on the outside of the tank for aluminum nuts and washers.
You probably could get away with stainless without problems. I used aluminum for fasteners because I could. I didn't check because I don't care but they are probably cheaper than stainless anyway.
Inspection port ID being 5" Dia. with a plate OD of 7", this size was about as small as I could go and still get my arm inside the tank. Bolts were spaced about an 1" apart around the plate.
For gasket material I used 3/32" Buna-N 70A Durometer rubber. For those who care to know Buna was invented by the Germans in WW2 as a natural rubber replacement when their access to Asian rubber plantations was limited. It is still used today.
I have a common leather punch but the holes were too small for the bolts I was using. Drilling out the center of a air hose nipple worked pretty good as a 5/16" hole punch. Then the whole thing gets assembled which is where the learning
curve happened for me.
The Permatex 2 Form-A-Gasket is a mess to work with. Glove use is encouraged and apply with an acid brush. A friend suggested using it on one side of the gasket only, the part side, not the tank side. This worked well on the first one I did. Because of some carelessness I had a tight fit on a couple bolt holes which meant that the backer ring held itself in place when I installed the cover plate.
On the second one I had proper clearance on all bolts which meant I needed to coat both sides of the gasket so it would stay in place when I dropped the cover down. Alternately if you had a friend who could hold the backer studs in place with a pair of knives until the cover was on and you could get a couple nuts in place you could just coat one side.
If I did it again I would just coat both sides to begin with. I felt like it acted kind of like a lubricant which allowed the gasket to move better when the bolts were tightened down. I dated the install so if the tank ever comes out again down the road we can see if it made any difference between the two.
Finally I did a pressure test with the shop vac and some soapy water
. Was it the same pressure as 3' of head
I would have if you overfilled the tank? Probably not, but let's just say I'm not planning on overfilling. I'll let you if I have any problems down the road but I'm pretty confident. I used the gasket sealant
on the threads on the backer plate and Anti-Seize on the nuts outside the tank just because I had it on hand.
Would I do it again? Of course. Should everyone else do it? Not for me to say. I could have cleaned it using other methods and maybe it would have been fine. For my some things are worth knowing with 100% certainty and this was one of them.