I’m going to be installing a cooling blast tube for the alternator.  I drilled a 5/8″ hole in the right ramp just above the alternator.

I purchased a couple of these flanges for 3/4″ SCAT tubing from someone on Van’s Air Force.  I put a socket inside the flange to help center it in the hole.

Here’s where the flange will mount on the bottom of the ramp.

I wrapped a few layers of electrical tape around the socket to perfectly center it in the hole since the fit was a little loose.  This worked like crap, don’t even bother.  I ended up having to drill new holes in the flange because it was so far off center.  Instead, just eyeball it and clamp it in place.  That worked perfectly.

I meant to post this a few days ago, but here’s the flange nicely centered in the hole.  I picked up some aluminum screen material to rivet between the ramp and flange to keep out bugs and debris.

I cut out the opening for the air filter.  This is significantly undersized and the opening will be made large enough to install the air filter from the top.

I then reworked the conical gusset a bit.  This is not normally installed with the snorkel, but I really didn’t like the way the cowl inlet intersection worked without it, so I’m going this route.  The edge of the gusset will cover up a very small amount of the filter, but there will be enough of a gap that air can still flow through the entire filter.  I replaced the aft most rivet in the gusset with an AN515-8R8 screw that goes through the ramp and snorkel mounting flange.  I added a second screw between the next two rivets forward (which both had to be reversed so that the flush head is on the bottom so that the shop heads don’t interfere with the filter flange).

There’s a third screw at the forward end of the flange, but this screw installs from the bottom because of the conical gusset.  The nutplates are K1100-08 for the flush head screws.

You can see that this screw goes into a K1000-08 nutplate that I mounted under the conical gusset.  I used an AN509-8R6 screw because of the tight clearance.

The other flange just has some more AN515-8R8 screws.  I’ll add a third screw at the forward end after I figure out how I’m going to deal with the bracket in the lower left.

I also replaced 6 of the rivets along the aft edge with ones that are flush along the bottom side since the aft snorkel mounting flange sits against this surface.

I then drilled three additional holes for AN509-8R8 screws that attach the aft snorkel mounting flange.

I also installed some K1000-08 nutplates along this flange.

Next up, I drill a 2 5/8″ hole in the side of the snorkel for the alternate air entry.

This flange will be mounted here and a pivoting cover will seal the opening under normal circumstances.  If the air filter were to become clogged, I could open this door from the cockpit.

The flange is drilled to the snorkel.  The center hole in the bottom of the flange needs to be match drilled to the snorkel using a #19 drill and then later opened up to 1/4″ in the snorkel so that the nutplate can fit through the hole.

Finally, I sanded and cleaned the surface and flange, then clecoed it down with some epoxy mixed with flox.  I then roughly faired in the flange so that there is a nice transition to the snorkel.  The flox leaves a fairly rough surface though; I’ll use some filler to smooth this out nicely after it cures.

I’ve been traveling for work recently, so I haven’t had much time to work on the plane.  I did manage to put a couple of hours in on the project today though,  First up, the mixture control cable interferes with the snorkel in the full lean position.  I marked the snorkel and will have to glass in a blister.

Next up, I mixed up some epoxy with flox and riveted the upper flanges on to the snorkel.

The rivets are flush on the inside (mostly) so that they don’t interfere with the air filter.

On the outside, small washers were slipped over the rivet shanks before pulling to spread the load out on the glass.

Finally, I mixed up some proseal and sealed the corners between the flanges to prevent air leaks around the filter.

Instead of cutting and glassing in a dimple to clear the mixture arm, I heated the snorkel with a heat gun and simply pressed in with my thumb to create a depression.  There’s just over 1/8″ of clearance now, but the mixture arm is only in this position when the mixture is in idle cutoff.  When the engine is running, the arm is no where near the snorkel.

I also opened up the hole for the alternator clearance a bit and then prepped four layers of 9oz bid cloth between a couple of sheets of plastic (this picture was obviously taken after I cut out the piece to be applied to the snorkel).

Here’s the glass applied to the snorkel.

I was having a hard time keeping the edges of the glass stuck down to the snorkel because of the tight curve, so I laid a piece of plastic over it and taped it tight.  I also wanted to keep the center depressed to provide additional clearance for the alternator bracket, so I taped a paper towel down over the depression.  I should have roughly 1/4″ of clearance between the snorkel and the alternator bracket.

I mixed up some West System epoxy and lightweight filler and smeared a coat over the snorkel.  This will fill the weave and smooth out the transition to the new glass I applied yesterday.  This stuff is pretty easy to sand, so I don’t have to worry too much about getting this really smooth right now.

I sanded most of the filler off.  This thing is baby smooth now and you can’t feel the weave or the transition to the new glass.  I still need to put some additional flox around the bolt holes since the surfaces aren’t parallel there, and this will get a skim coat of pure epoxy to fill any pin holes.

I accidentally left my master switch on a couple of weeks ago, and my battery was dead.  I mean really dead (1/4 volts).  It was so dead that the charger wouldn’t even charge it since it didn’t think it was connected to a battery.  I ended up tricking it by hooking up my bench top power supply in parallel with the battery.  This let the charger see about 12V, which was enough to trigger it into starting to charge the battery.  It’s a little hard to see in this picture, but I have three multi-meters hooked up in addition to the battery charger and bench top power supply.  One of the multi-meters is monitoring battery voltage while the other two are measuring current delivered by the power supply and battery charger respectively.

The battery is fully charged again and appears to be none the worse for the abuse I put it through.  The real test will be when I try to start the engine for the first time with it.

I finished filling the snorkel.  You can see a little bit of the reddish flox mix around the holes used to attach the snorkel to the fuel injection servo.  I did this to make the forward surface parallel with the aft surface so that the bolts would apply even pressure to the flange.  Afterward, I applied a coat of pure epoxy to fill any pinholes and seal the surface.  After a final sanding, this is ready for primer and paint.

The plenum mold I purchased was made on the old non-pink cowling and made the inlets too narrow to work on my cowling.  I cut off the ears and made a little mold with some stiff paper covered in packing tape.  The paper is attached to the other side (which is the top side) of the plenum mold with double-sided carpet tape.  I used four layers of 9 ounce cloth.  The dark lines along the edge of the mold and along the apex of the curve are epoxy/flox fillets to allow the glass to drape smoothly down onto the paper and to provide a hard corner along the apex of the curve.

I peeled off the paper and used some epoxy with lightweight filler to fill in the little gaps and provide a smooth surface to lay up the plenum.  I’ll sand it all down tomorrow and see how it looks.