Engine Details

Just a little update since I have not posted in a while. It got really cold here and my progress has been slowed considerably.  I have been working on the engine installation and finishing the instrument panel. I started by fitting the exhaust system and measuring it before I send it off to Dawley for rework/modification. Piper never made a exhaust system for the -12 engine installed in a stock J3, so every one is custom made. This is the problem area,

The oil screen housing on the -12 engine is on the right side and much lower than on the -8 series engines. After removing the muffler shroud I was able to install the screen housing and get some accurate measurements. I calculated that for my airplane the muffler needs to be 1 inch lower.

After documenting all this I sent the two stacks off on Monday, they say they are swamped right now so it's hard to say when they will come back. I hope they can reuse the stamped collectors, otherwise they will make new ones from round pipe. On the left side they just change the angle of the long pipe.

  On the right side , they change the angle and increase the length of the two riser pipes.

It will all look as nice as the muffler when I get them back. They did the muffler last year. I then completed the installation of the oil pressure gauge. I got the new flex line from Univair ($85 !!!) it has the restrictor fitting built in and the original auto type fitting on the other end. Per original I used 1/4 inch copper tubing , I sleeved it with vinyl tubing to protect it from chafing.  Here is the final install,

Here is a shot of the inside, I still need to run the primer "out" line and this side will be finished.

Today I worked on the tach cable, cabin heat, and throttle.

To avoid sharp bends the tachometer cable curves up over the mount then back into the rear case. The throttle exits the firewall next to the tach cable, and the cabin heat comes through the upper hole. I sleeved the cabin heat cable with vinyl tubing because I have the old style heat box and it tends to chafe inside the cowling. This shot shows the control attachment at the heat box.

The throttle will have to wait until I get a chance to paint the special mounting clamp, and the return of the exhaust pipes. I did run into a little problem with my fuel drain system. If you remember I ran the drain line all the way back to the rear corner of the boot cowling. The problem was that when the drain was released the vacuum created would not let the remaining fuel drain from the line. I solved this by incorporating a vent in the drain line, it works great now.

 I have been told that this is the case even without the extended drain tube.That's it for visible progress, hopefully after the snow/freezing rain tomorrow we will get back to seasonable temperatures next week.