Oil Cooler Fittings and Seals

Posted on by Neal

Tonight I installed the two fluid fittings on the oil cooler, and the two rubber seals which will sit between the oil cooler and the air inlet.

The fluid fittings were easy enough. Vans published a video of this procedure, highlighting the need to use two wrenches to avoid torquing (and cracking) the oil cooler. The cooler is made of fairly soft aluminum, and cannot handle the torque needed to seat the fluid fittings. There have been cases of oil coolers failing in flight, and even a recall on a batch of coolers (mine is not affected).

I followed the video, measured the clocking angle, and installed the two fittings.

Then I proceeded to apply silicone adhesive to the sides of the top of the cooler, and followed the instructions to glue down the two seals.

I also spent time filling in the remaining gaps on the inlet where I missed a spot or two when applying RTV last night.

Oil cooler
Installing the first fluid fittings
Both fittings installed. Note the two wrenches used, one to hold the nut on the cooler, and one to torque the fitting
Beds of silicone adhesive applied
Seals glued down
Close up of the left hand seal

Bottom Cowl Screws

Posted on by Neal

Tonight I finished a job on the cowling, locating and drilling the screw attach points on the trailing edge. There are a total of 8 holes, 4 in the middle section, and two more on each side. There’s a template supplied for the outboard holes, so I made the template and drilled those outboard holes, then attached the heat flap to locate the 4 center holes.

I was careful to not drill into the nut plates, which would cause them to lose their ability to hold the screws.

Making the template. Simple cutting a part into two and using one half
Template taped into position.
Template taped into position
Heat flap temporarily installed overlapping the cowling. This gave me the locations for the 4 holes in the cowling. When finally installed, the heat flap goes under the cowling.

Dip stick

Posted on by Neal

Tonight I installed the dipstick on the engine. Just a few minutes of work to screw it into place, I still need to torque this and safety wire it, but I don’t have a big enough crow foot to complete the task.

Plastic cap removed
I used food grade anti seize per the engine manual
Screwed into position

Control cables

Posted on by Neal

Today I was able to spend a few hours working on the airplane. I managed to get all of the control cables installed and routed. I appear to have a control interference issue between the pilot stick and the throttle, and looks like I need to remove half an inch off of the left control stick. However, I need to measure the amount of throw in the aileron pushrods, because it might be that the stick can’t actually move that far horizontally before the bell crank hits its limit.

I was able to connect the prop and alternate air controls, and the mixture and throttle connected. I can’t connect the heat flap actuator until I finish drilling some holes in the bottom cowling.

The routing through the wiring under the panel worked out ok. The prop control was just barely long enough, but I think it’ll work ok. I have loosely connected it for now to ensure I have the right length and throw on the lever. The alt air works great, and the mod from aircraft specialties, allowing the door to open and close, is a nice upgrade.

Controls
Controls
Throttle cushion gap. This is a larger gap than is called for, but I can’t get anything less than this without it being too small of a gap
Behind the control bracket
Under the panel. In the top right you can see the somewhat messy routing of control cables through (actually above) the wiring bundles
Heat flap control
Throttle cable attach. Blue tape indicating this is not final torqued
Mixture control
Throttle and mixture controls

Control Cable Bracket

Posted on by Neal

Tonight I started working on the control cables. Vans sent me the correct control cable bracket, which has an extra hole for the cooling flap, and a redesigned layout. It’s made from slightly thicker material and feels solid. I was able to prime it yesterday, so I mounted it tonight. I also trimmed the alt air cable and the cooling flap cable. The cooling flap cable has a push-button release mechanism, which uses a small ball bearing to create the friction necessary to hold the cable in whatever position it’s set. The instructions have you pull the knob out 6 inches, then cut the end of the cable. At about 5 inches, the ball bearing is exposed and falls out if you aren’t careful. I noticed this and put the parts into a zip lock bag while I trimmed the cable, then reinstalled it. It would be a major pain in the butt if the ball bearing fell out onto the floor, I would never find it!

The cabling under the panel is going to present a challenge for routing these control cables, but I plan to pass each cable between the cable bundles and the mounting frame I built forward of the sub panel. It should work ok, although I’m sure I’ll run into some kind of challenge.

Original bracket on the left, new one on the right
The cooling flap control. Barely visible is the small hole where the ball bearing sits, just above the “2” on the ruler.
The ball bearing, spring, and button which forms the grip mechanism inside the cooling flap control cable handle.

Engine Sensor Wiring

Posted on by Neal

Tonight I wired up the Manifold Pressure, engine oil temperature, and fuel pressure sensors. I wanted to finish the job and wire up the oil pressure sensor, but I ran out of butt splices. I tested the sensors by powering up the instrument panel and looking for signals. I was happy to see all of the gauges reporting data correctly.

I also took the opportunity to test and adjust the canopy unsafe warning. At first the canopy pins weren’t contacting the micro switch, but after a quick adjustment it now works great.

Oil temperature sensor wiring
Typical connection between sensor and wiring harness. I used butt splices because I don’t want these to come apart in-flight, and I have plenty of wire length to allow cutting and re-doing this if I even need to replace the sensor

Heat vent controls

Posted on by Neal

Tonight I installed the two heat vent cockpit controls. These are push/pull controls that are mounted on the instrument panel and open the heat vents, one pilot side, and one passenger side.

No real challenges installing these controls. I was careful to ensure I had a 1/16 cushion gap when the vents are fully closed. This will be more critical on the other controls, but it was good practice.

In the process of reading through the plans I made a couple of realizations. One is that I have the wrong version of the control mounting bracket. The version I have is labeled as the updated part number with a -1 at the end, but it’s actually the old version. I emailed Vans to confirm, hopefully I can get a new one quickly. I could just make a new one, but locating the holes would be time consuming. Unfortunately I’m blocked on the rest of the control cable install steps until I have that bracket in-hand.

The other realization is that my panel wiring harnesses are going to be interfering with the control cables. I can probably make it work, but will need to look out for chaffing problems in places where the wiring bundles and control cables are touching.

The control cable collection
Pilot side cabin heat control
Passenger side heat control
The mechanism to open and close the heat vent. These are on the firewall.
Routing of the control cable

Oil cooler

Posted on by Neal

After a 10 day work trip to India I was able to accomplish one small task tonight. I cut and deburred these spacers for the oil cooler. Right now this is about all I’m going to do with the oil cooler. I’m hoping to pick up a 3D printed oil cooler plenum to replace the standard Vans model. The 3D printed plenum will be circular to match the circular scat tube, vs. the square cornered Vans model. Based on what I’ve read and been told, there should be some improvement in oil cooling efficiency using this modified plenum. It’s currently in testing and not ready for production, but hopefully will be ready near the end of the year.

I also took a few minutes to confirm that my oil cooler serial number is not in the range impacted by the service bulletin issued earlier this year. https://www.vansaircraft.com/service-information-and-revisions/sb-00080-rev-2/

Oil cooler spacers