Category: Engine Controls

More Work Firewall Forward

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Updated: April 4, 2020

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March 6, 2020 – I continued to whittle away at the little chores that need to be done forward of the firewall.

I don’t have a picture, but I connected the vacuum hoses to the P-Mags. I’m still not sure how my final manifold pressure installation will look.

I continued to clamp lines and hoses.

I bought a dust cover for the engine tach drive.

I also drilled a hole in the lower cowl for the fuel drain line. Here’s the location mark for the hole.

I drilled the hole in the lower cowl. Here’s the drain line with the cowl installed.

Time: 1:45

Category: RV-7, Engine Accessories, Engine Controls, Firewall Forward

Moved Throttle Cable

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Posted: February 2, 2020

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February 2, 2020 – I moved the throttle cable at the firewall so it will come through the cabin heat box at a better location.

I loosened the eyeball in the firewall and turned the cable straighter. The first picture shows the upward orientation of the cable. The second shows how the cable will enter the cockpit through the access panel in the heat box. I’ll put a grommet in that panel later.

Time: 1:10

Category: RV-7, Firewall, Engine, Engine Controls, Firewall Forward

Engine Control Cables and Throttle Quadrant

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Posted: January 16, 2020

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January 16, 2020 – I “permanently” installed the engine cables and got them close to a final rig.

Not a lot of pictures for a lot of time spent.

I did finally assemble the mounts for the throttle quadrant in the cockpit.

One small issue I have is on the dust seals for the cables. The rubber boots got damaged during the repeated removal and installation of the cables.

Here’s one of the boots I’m talking about:

One of the cables lost the boot entirely:

After consulting with a few people I trust, I decided on a fix. I’ll install heat shrink at that location on each cable.

Time: 4:40

Category: RV-7, Engine, Engine Controls, Firewall Forward

Alternate Air Door

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Posted: October 10, 2019

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October 10, 2019 – I installed the alternate air door in the snorkel.

Alternate air provides an unfiltered air source for the engine in the event there is a blockage at the air filter. I went with the stock door supplied by Van’s. This door is a one-way door, meaning once it’s opened it can’t be closed in flight.

The snorkel has a flat area that is the location for the door. A hole is cut the for the adapter ring.

The tab on the top gets bent down, then crimped on one side. This provides a stop forthe door when it’s closed.

I riveted the ring in place including the nut plate for the hinge, then faired with resin and flox.

I attached the door. I’m going to wait on the cable until everything else forward of the firewall is going in for good.

Time: 1:10

Category: RV-7, Engine, Engine Accessories, Engine Controls, Firewall Forward

Replaced fuel mixture arm

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Posted: July 9, 2019

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July 9, 2019 – I needed to replace the mixture arm on the fuel servo.

When installed, the bolt in the arm that came with my engine just barely touched the starter. The Precision part number was 2521196.

I called Precision’s Product Support. I got the somewhat reasonable suggestion to remove the starter and hand-prop. Ha ha. Then he said that if I sent this arm in, he would swap it out with a shorter one. The other alternative was to pay $200.00 for another one.

I got the replacement arm a few days later. Put it on today and it’s a thing of beauty. This part number is 2521287.

On to other things…

Time: 1:00

Category: RV-7, Engine, Engine Accessories, Engine Controls, Firewall Forward

Continued engine cable installation

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Updated: June 5, 2019

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June 5, 2019 – I started to permanently install the engine cables. I’ll be glad when this is done.

I’m using the aluminum firewall eyeballs from Vans. I had previously drilled the holes in the firewall; I routed the cables through them and partially installed the eyeballs. Have a couple of issues with the attaching screws; I need to order a few more.

I connected the business ends of the cables. Here’s the mixture bellcrank:

I’ll post better pictures of each connection when they’re done.

I’m still working on connecting the cables at the throttle quadrant. I may grind each clevis down a little bit for clearance, since they’re so close together, but it’s pretty good as it sits right now.

Time: 3:45

Category: RV-7, Engine Accessories, Engine Controls, Firewall Forward

Made engine control brackets

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Posted: January 24, 2019

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January 24, 2019 – I made the brackets that I needed to install the engine cables.

I ordered a 12″ x 12″ sheet of .063″ 4130 steel from Spruce. I made the new extended throttle cable bracket and the angle that mounts forward of the throttle quadrant to secure the cables there.

Here’s the old and new throttle cable bracket for comparison:

I’m waiting to get my modified mixture bracket back, then I’ll have all three pieces powder-coated.

Time: 1:20

Category: RV-7, Engine, Engine Controls

Engine Control cables, continued…

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Posted: January 10, 2019

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January 10, 2019 – I have had some real trouble with the Prop control cable and the governor. With everything hooked up, including the cable at the throttle quadrant, I can’t get the governor arm to contact both stops. I can reach the high RPM stop, but I haven’t been able to touch the low RPM stop. The closest I’ve come is about 3/16″.

So after wasting a lot of time, I’ve decided to go ahead and install the cables, then see what RPMs I get when I run the engine, and go from there.

To back up a little bit, I couldn’t use the 48″ cable at all. It was several inches too short for the throttle control. I bought a 49.5″ for the throttle, I’m using 52.5″ for the mixture, and a 55″ for the prop. An EAA friend had the 55″ for me to try. It worked, so I gave him the 48″ for later use.

I bought AN486 clevises from Aircraft Spruce for the connections at the quadrant. Because of interference, I do need to narrow them a little bit and use slightly shorter pins, but this will work. This photo is from underneath the quadrant, looking up:

I got three firewall grommets from vans. These are the ones with the aluminum balls that clamp the cable. I took the holes in the firewall up to 1.079″ with a punch.

 

Then I made a template for the backplate screws, and drilled and deburred those.

 

I had to drill the holes in the balls up to the final size for clamping the cables. I went to .328 using a series of drills and reamers.

I have to make a new bracket to attach the throttle cable at the engine. The one I got from Vans in the kit needs to be lengthened by 1.5″ to accommodate the cable. The mixture bracket for the bellcrank was previously modified to fit; a friend from work is beefing it up by welding a gusset to it.

The aluminum bracket I made to secure the cables at the quadrant had an issue. I was getting ready to shape it and get it ready to paint, and I found a crack in the radius. So I ordered a sheet of steel from Spruce to make what I have to make, then I’ll get everything powder-coated and installed.

Time: 9:00

Category: RV-7, Engine Controls, Firewall Forward

Working on control cables

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Posted: November 15, 2018

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November 15, 2018 – Well, I complicated my own life by going with a throttle quadrant for engine control. I’ll be so glad when this part gets wrapped up.

I drilled holes in the firewall at the suggested locations for the throttle, prop and mixture cables using my punch set. The holes are 1″ right now, just large enough to pass the cable nuts through. I believe the final hole sizes will be 1 1/8″ for the cable pass-throughs I’ll get from Spruce.

I bought a 48″ and two 52.5″ cables. When I got them I routed them through the firewall to test fit. I used closed-cell foam to protect the cable jackets from the stainless edges.

I already know the 48″ cable is too short for the throttle. As near as I can tell, I need 51″. I’m waiting to order until I’m sure about the rest of them.

I had to slightly re-clock the prop governor because the cable went over-center at full travel. I also bent the bracket for the governor for a straighter cable approach.

Along with figuring out what cable lengths I need, I also need to make sure those cables are secure so I can get an accurate idea for routing and their lengths. The cables will be secured behind (forward of) the quadrant, so I started prototyping a bracket for that. Here’s my first one:

…and my third:

I think this one may be in the ballpark. I also ordered Aircraft Spruce part #05-01437 which is an AN486 with a 10-32 thread. These should have a deeper throat for attachment at the quadrant. I wasn’t getting full travel at the quadrant because the shorter clevises were hitting the arms. They are on the way.

Time: 6:30

Category: RV-7, Engine, Engine Controls, Firewall Forward

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