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Firewall eyeball

S

Smilin' Jack

Well Known Member
I have seen several different types of firewall eyeball assemblies for the throttle, prop and mixture cables to run through. I like the Aluminum single cable design that requires a 3/4 inch hole in the firewall but what size do you need for the internal hole that the cable actually goes through. Do you have a part number? what is the diameter of the cables?

The item is located in the spruce catalog on Pg 145 and is model number TTP in the column to the right.

Thanks
Smilin' Jack
 
My $0.02

I have three or four of the TTp aluminum eyeball firewall assemblies that you can have. They are gouged and bent, a result of me taking them off in order to replace worn cables. The fine aluminum threads get galled and there is no wrench in my considerable collection that will hold those things secure enough to get them apart without ruining them. Plus there is no way you can install or remove them without it being a 2-man job. (One on either side of the firewall.) In my humble opinion they are c##p! I went with the SE961 assemblies and will never go back.
 
Here's the answer to the rest of your question

Copied from Aircraft Spruce for Internal Hole diameter, depending on what cables you are using.

.125 - Oil pressure, primer
.188 - ACS cable, 730, 740, 1770, A1780
.218 - Bowden Cable
.240 - ACS cable, 700, 1340, 750, 770, 780, 790, 800, 810, 820, 920, 930, 950, 960, 970, 1550, 1600, 1750, 1760, 1860, 1870 and 1970
.250 - Tubing
.260 - Tachometer cable
.375 - Tubing
They can be drilled larger if necessary, in small increments (1/16 at a time or so).
Hope that helps, plus what Dan said.
 
My results with the steel eyeball

I posted a few years ago about the internal sizing for the eyeballs because it was confusing trying to figure it out just by looking in the catalogs.
That is here:

Eyeball post

The results were that I did buy the 0.240 diameter ID ball and I trimmed the sheath off the cable right in the area where the ball needed to grip the cable.
Everything fit fine.

I used the ball for my prop cable. My other cables were done with the flanged tube and firesleeve type of pass through.

I learned one additional thing and that is that the eyeballs are NOT airtight at all. I filled the cabin side cavity of the ball with proseal to make it airtight.
 
I learned one additional thing and that is that the eyeballs are NOT airtight at all. I filled the cabin side cavity of the ball with proseal to make it airtight.
Click to expand...

Face the cavity in the ball toward the engine side and fill it with 3M FireBarrier 2000. There will be nothing to smoke or flame inside the cabin, and the sealant will be intumescent, i.e. the material will swell when heated, maintaining a gas tight seal as insulation melts off the wire.
 
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Thanks for all the post... thanks Dan. and Ron and everyone for the answers.

I guess i will continue to ponder... I have a little time left... Just fitting the wheel pants..

I'll be ordering the engine in March, I understand i have a 6 week wait.

Smilin' Jack
 
hole dia.

Jack, I don't know if you have a lathe available, but I purchased all .125 dia. eyeballs. Then as I needed them I put them in the collet chuck, lined the two haves with a dowel pin, and bored them to whatever size I needed. You can deburr and chamfer to avoid cable damage in the future. A nice option if you have access to a lathe. Ron
 
How are these things assembled?

I have SE961 eyeball fittings and, embarrassingly, I can't figure out how they are supposed to be assembled to the firewall. There were no instructions and the catalogue photos are no use.

Has anybody got any photos showing them fitted to the firewall?

Also, the standard Vans (carb engine) hole locations do not allow SE961 fittings to be used for all of the penetrations as the throttle and carb heat holes are too close. Can the Carb heat hole be moved or is there an alternative approach?
 
Firewall eyeballs

Loman, here are a few shots of my eyeball fittings as I was installing them for the various control cables. Hope this helps.

5ujsjq.jpg



fcjqqp.jpg
 
I really don't understand why folks like these eyeball things when you can drill one hole, put a stainless flange on, run throttle, prop, and mixture all thru the same hole, and seal up the end with firesleeve and a clamp just like you do for wire and cable. And not spend upwards of $100 for three. One hole, done. Nice and clean too.
 
rocketbob said:
I really don't understand why folks like these eyeball things when you can drill one hole, put a stainless flange on, run throttle, prop, and mixture all thru the same hole, and seal up the end with firesleeve and a clamp just like you do for wire and cable. And not spend upwards of $100 for three. One hole, done. Nice and clean too.
Click to expand...

Well Bob, for me, I am not anywhere near as experienced as you and others so we blindly follow Van's instructions and drawings. There is a cable location call-out for various cable holes and they are not in the same place. I can't say I disagree with your approach but most of us don't get "experienced" on the first build. Maybe my next build will use your philosophy. Thanks for your input though. I always look forward to your experienced replys to building threads.
 
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Thank you for the kind words Gary, thats precisely why I enjoy sharing experience so we all get better and safer. Its amazing to me how many parts and system designs have been repeated ad nauseam in Van's designs without real improvements. Somewhere down the line someone thought it would be neat to use these aluminum swivel fittings on the firewall but to me they're a hazard if there was a raging fire, and they really don't functionally improve improve anything.
 
Bob is right.

These cost less than $2 and are better than anything you can buy. A length of tubing, a square of sheet, a minute to weld. You can cover them with silicone firesleeve like Bob said, or just pump them full of an intumescent silicone as you see here.

jl6z5e.jpg
 
cropdusterdave said:
Bob, you dont have a pic of that do you?
Click to expand...

I'll take one. Its pretty simple, just a chunk of stainless turned down on the lathe into a short tube with a flange and pop riveted to the firewall with stainless rivets. On mine throttle, prop, and mixture go thru the same hole. Granted a lot of folks here don't have lathes and mills and whatnot but here is something that is essentially identical: http://www.safeair1.com/averytools/firewallpassthrough.php With the exception that mine cost essentially nothing since the chunk of stainless came out of my junk pile. I believe it was 303 since it turned nicely.
 
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Cool. Looks like they have the same thing at spruce for 40ish bucks with all the sleeving, clamps, etc. im all for cheaper, easier, better...
 
It isn't quite the same, but firewall related. I changed my 9 to a 9A. This involved moving the brake lines from the engine side of the FW to the new gear mounts. I had to cover the holes and couldn't find a piece of stainless steel. I did have a blank cover plate that was stainless steel. I cut it, deburred, and fit it over the holes. I will use 3M firestop 3000 before I bolt it with stainless steel bolts.

Does this look like it will work? I thought of making some of the other sleeves with cover plates. You can get them up to about 4"x4". A bit of tubing welded on and you have a nice sleeve.
ss1.jpg
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ss3.jpg
[/IMG]
ss2.jpg
 
You learn stuff all the time.. I happen to call Van's and they told me thy use a snap bushing and cover it with high temp RTV silicone , Ken stated after both ends are fastened where is it going...
Well I did use the steel eyeball
Smilin Jack

Ps...after 3 weeks on back order I got my prop cable from Van's
 
Bath Tub Grab Rail

rocketbob said:
I'll take one. Its pretty simple, just a chunk of stainless turned down on the lathe into a short tube with a flange and pop riveted to the firewall with stainless rivets. On mine throttle, prop, and mixture go thru the same hole. Granted a lot of folks here don't have lathes and mills and whatnot but here is something that is essentially identical: http://www.safeair1.com/averytools/firewallpassthrough.php With the exception that mine cost essentially nothing since the chunk of stainless came out of my junk pile. I believe it was 303 since it turned nicely.
Click to expand...

You can buy just what you need in the Aviation section of your local Home Depot or Lowes. I got this idea from Bob Nuckholls. Purchase a SS bath tub grab bar. Cut off the center section and you are left with two nice flanged stainless steel pass through tubes. They come in several tube diameters.
The flange [complete with drilled mounting holes] are hidden under those round trim covers. For a straight through tube, just cut before the 90 degree bend. That is best for control cables. For electrical wires, Bob recommends cutting after the 90 degree bend. That way, a FWF fire is blowing on the SS tube, not directly on the intumescent filler or fire sleeve. At the very least, you have eliminated a "straight shot" for the flames, if the sealant fails. The 90 degree bend will also let you route the wire harness closer to the firewall. You have more places to support the harness by keeping it near the engine mount.
See links below for ideas. FYI, they also sell "off brand" versions for less money.

SSBathGrabRailforFirewallPassThrough_zpsf27cd805.jpg


See

http://www.homedepot.com/h_d1/N-5yc...inless+steel+bath+tub+grab+rail&storeId=10051

http://www.homedepot.com/h_d1/N-5yc...inless+steel+bath+tub+grab+rail&storeId=10051

Charlie
 
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