Trim top cowling to a straight line to match lower cowling.
Shim front of cowling to make outside smooth. Hold shims in place with tape or bond them in the positions of the fasteners.
Drill and cleco top to bottom with shims in place. We recommend that you have a 1/8" to 5/32" gap between top and bottom cowlings to make inside cavity larger).
- Always make sure the cowling is level and centered. - It is easy to trim, but not so easy to add. Be careful not to trim too much.
Install cowling on engine as a unit with inner duct loosely in position. make sure cowling is centered on prop spinner with appropriate gap.
Check for 3/8" to 1/2" clearance between duct and exhaust heat shroud, if you have our heat muff. If you don't, you should have an additional 5/8" more space. You will need to block the bottom of the cowling in position to prevent it from sagging down.
Mark the back edge of the cowling on the boot cowl with masking tape.
Remove cowling and check for edge distance for cowling to boot cowl. You will need to trim the boot cowling and the cowling so you have nice straight lines with proper edge distances for the fasteners. This will require removal and installation several times. Its easy to trim but hard to add so be sure before you cut.
With the top cowl cleco'd to the bottom cowl, drill and cleco the cowlings to the boot cowling.
Upsize holes in top and bottom cowl and install fasteners. (screws and anchor nuts or our Sky-bolt Cowling Fasteners)
Install lower duct on cowling. This works best if both cowls are installed on aircraft so that there is less chance of warpage.
Cut out and install your naca air scoop on the right hand side of the bottom cowling. It should be parallel to line of flight which will be close to the cowling seam line. Once again both cowls installed to prevent warpage.
You will notice that on the lower corners of the bottom cowling that the cowl does not match up to the boot cowl at the same angle. There is a gap of up to 3/8". we recommend you fill this with fiberglass in a localized area around the fastener on the cowling or over a larger area in the boot cowling. Doing it on a large area on the cowling may stiffen it up too much, making it hard to remove or install.