Firewall installation: Install engine and all engine plumbing/wiring prior to installation of firewall. Carefully measure where holes should go, then drill firewall holes, install rubber grommets, pull engine, install firewall, and re-install engine running the plumbing/wiring through the appropriate holes. Put aluminum tape between firewall and any dissimilar metal. RTV the firewall in place for corrosion protection.
Firewall: I have installed the firewall pretty much according to the manual. Be sure to wear gloves when handling that stainless steel. It cuts skin very fast–have bandaids handy. If you are this far along, be aware (also BEWARE) that the bottom two engine mount bushings are 5/16 shorter than the upper so it requires 5/16″ of washers or spacer in mounting the engine! (Not the best system in my mind!) I was told by Chris K. that this is so that they can mount some of the float support system here. The firewall can “oilcan” very easily, so I wanted some kind of insulating firewall blanket on it to prevent that, as well as to provide fire protection and heat and noise insulation. I have installed a section of fiberglass insulation (4″ thick – compressed) from my shop building. It has a fiber reinforced facing on it which I have placed on the aft face. (I tried to find some foil backed type but was unable) It makes a very close fitting, tight installation. Be aware (again beware) that the attach tabs (10 of them!) are located about 1/8″ to 5/16″ aft of where the firewall ends up, due to the fwd face of the engine mount bushings protruding about 1/4 to 5/16 fwd of the attach tabs. The attach tab screw bolts will thus require washer shims. But of course the ones supplied are too short for that, so you must procure longer screw bolts for those 10 attach tabs. The hi temp nuts for these screw bolts were not in my kit, and not available at this time from S-H. (Chris said that their supplier sent them the wrong ones) I plan to go ahead and just put regular ones on rather than wait for them. ( If I have a fire that is so hot it melts those attach tab nuts off, I figure I’m dead anyway!) If you don’t do this you will have a distorted fire wall, vs a straight one. Also, in drilling holes through the fuselage/ cowl joggle, I drilled from the outside in. easier that way!
Firewall insulation: I purchased the firewall insulation kit with double sided aluminum from Unlimited Quality Products, 710 W. Broadway Road, Suite 508, Mesa, AZ 85210, 800-528-8219. They were at OSH and I looked at their basic two-sided insulator kit. I also bought the Sticky Stuff Spray Adhesive and the Insul-Tape. Total cost about $27, but they make it up on the shipping cost which I thought was too high, but it still comes out a relatively cheap kit. 😉 I don’t know how good it will be about cutting down sound, but it should work relatively well with the heat. It’s not heavy or too thick. It’s easy to work with.
–Joseph A. (Joe) Colquitt
Firewall installation: I have installed a 1/8″ thick piece of polycarbonate plastic (drills without cracking) as a dummy firewall. I will then install the engine and will mark and drill the plastic sheet, which is actually a customized template, to position everything to my liking. Then I can remove engine/mount, remove the plastic, and use it as a template to drill out the steel firewall. I plan to undersize the drilling of the cage tab holes in this process, then final drill them from the rear on final installation. Everything else should be properly positioned.
Note: If you plan to mount the perimeter sheeting tabs behind the main sheet as opposed to in front as shown in the existing manual instructions, you will need to undersize the template all around the perimeter, about 1/8″, to account for the bend radius and thickness of the perimeter steel. Use your engine mount bolts to move the plastic template forward enough to see where you need to trim.
Firewall extension: I just finished trying to install the engine for the first time today. The trick mentioned before to make a “bullet” as a chaser to the engine mount bolts works like a charm until the bullet comes shooting out of the hole, and disappears on the hanger floor, yet to be found.
My governor for the CS prop did not clear the firewall, so an emergency trip to Kmart aircraft supply was made to buy a 7 inch stainless steel mixing bowl. This extends the firewall to clear the governor. This is a recommended RV trick, so I cannot take credit for the idea.
An hour and a half later I had the bowl Monel riveted into the firewall with a high-temp sealer providing the desired seal. You flatten the rolled edge of the bowl with your pneumatic rivet squeezer prior to riveting.
–John Steichen 5467