Exhaust System (Part 4)

The following work was completed on Saturday, February 4, 2023.

Now that the exhaust has been installed, I started installing the Exhaust Gas Temperature (EGT) and Cylinder Heat Temperature (CHT) probes.  In the “Avionics and Panel” section of the blog, I talked about my decision to use Garmin Avionics and to have our panel built by Aerotronics.  When Aerotronics shipped me the panel, the EGT and CHT probes were supplied with the panel.  The probes they supplied were from the Thermocouple and Probe company Alcor.  This link specifically discusses the EGT probes and this link discusses the CHT probes.

I followed the instructions provided with the probes (same as directed to in the links) and installed the EGT and CHT probes.  In the two pictures below, I circled the four EGT probes and used arrows to point to three of the four CHT probes.

During the next work session on the Exhaust System, I will connect the EGT and CHT probe leads to their correct instruction leads from the Garmin GEA24 (Engine Indication System).  This step will also require wire runs to be figured out, connections covered with heat shrink and wire runs secured properly with adel clamps where necessary.  Still a fair amount of work to compete the probes install.

Exhaust System (Part 3)

The following work was completed on Friday, February 3, 2023.  

I started this work session by making the Forward Exhaust Hanger Brackets.  The first step was to modify two of the Exhaust Support Tubes.  Each tube had to be be cut to a length of 3 1/4 inches, have the corners of the bolt end rounded and the opposite end flared.  This picture only shows the rounded bolt ends of the two tubes.  Next, I used a band saw to cut the tubes to the appropriate length and flared the opposite end. (More on that below).

 One of the tubes is bolted to the Oil Sump and the other tube is bolted to an Exhaust Hanger Bracket.  The tubes are then joined together by using a length of rubber hose secured by two stainless steel hose clamps.  As mentioned earlier, the idea behind flaring the opposite end of the support tube is to create a lip preventing the rubber hose and hose clamp from sliding off the tubes.  

**Regarding the flared end of the tube:  the instructions say to use a vice to compress the end of the tube (to values shown in the plans), thus making the lip.  I’m sure the process works fine, but I didn’t really like it.  So, since all that is needed is a lip, I used a tube flaring tool to create a perfectly round lip all the way around the tube.  (Be careful not to make the flare to large or it will be difficult to insert it into the hose).  I liked the outcome this process produced on the tube.  The pictures below show a couple views of the completed and installed Forward Exhaust Hanger Assembly.

Next, I installed the Heat Muff Assemblies.  The assemblies are installed by first connecting the two stainless steel rods to the four Heat Muff Ends (two separate pieces make up each end).  The plans specify the length from the outside edges of the Ends should be approximately 7 3/8”.  The assembly is held in place by friction resulting from bending the inner “teeth” of Heat Muff Ends inward to create a tighter clamping force when the rods are installed.  This is the forward assembly….the rear assembly is installed in the same manner.

The Heat Muff Skin is now installed around the assembly and secured with stainless steel clamps around the Heat Muff Ends.  This is also the Forward Heat Muff.

This picture shows the forward and aft Heat Muffs completely installed.  There are six sections of Scat Hoses that now need to be installed.  I will wait until I finish running all the control cables, wires, etc before I install them to allow space to work.

Exhaust System (Part 2)

I was able to install most of the exhaust system from February 2 - 5, 2023.  This post is from the first session on Thursday, February 2nd.

Previously, I had explored other options for the exhaust system due to the backordered status of the Van’s supplied exhaust (at one point I was told 6-8 months).  Lucky for me, that time frame was greatly reduce and I received the Van’s supplied exhaust in a couple of months.  I had always wanted to use the Van’s supplied exhaust in the first place…..it was “designed” around the IO-390, Van’s used it on their prototype, it fit in the cowling, the install should be easier, etc.

I can say, the install of the exhaust system up to this point, has been very straight forward and has required NO modifications to anything.  It went together according to the plans and bolted to the engine perfectly…..couldn’t have been any easier!  (I know, famous last words)

Here is the exhaust (minus the heat shrouds) “connected” and ready to be lifted to the engine.  It did, however, take me SEVERAL minutes of spinning and flipping the plans around and holding up exhaust sections to make the picture in the plans make sense.  But, I eventually figured it out.

To begin the install, I had to remove the four blanks installed by Lycoming when they shipped me the engine.  (One for each cylinder).

When I ordered the engine from Lycoming, they sent it to me with preservative oil in it (which I requested) for long term storage…..the sticker on the side of box translated that to six months under “ideal conditions”.  When I took the blanks off the cylinders, about an ounce or so of the preservative oil also came out.

Here is where the blanks were installed for cylinders #1 & #3 (on the right side)…..

…..and cylinders #2 & #4 (on the left side).

Here is three angles showing the exhaust initially installed in place on the engine.