Results 1 to 28 of 28

Thread: Bonding Strap

  1. #1
    Eddie Foy's Avatar
    Join Date
    Dec 2014
    Posts
    2,871
    Post Thanks / Like

    Bonding Strap

    I assume #8-Bonding Strap is to ground the engine to the mount??

    Is the #5-pin necessary?

    8BDBB1B6-C924-4F88-BB22-837C6E78520C.jpeg
    "Put out my hand and touched the face of God!"

  2. #2
    www.SkupTech.com mike mcs repair's Avatar
    Join Date
    Aug 2004
    Location
    chugiak AK
    Posts
    9,539
    Post Thanks / Like
    yes... it's useless junk

    instead use a short #8 wire from a bolt in firewall to a bolt on back of engine itself.....

    Ignore those that are going to say that's to small of a wire...

  3. #3
    Eddie Foy's Avatar
    Join Date
    Dec 2014
    Posts
    2,871
    Post Thanks / Like
    Thanks Mike. Then I can do away with them? I can't see how they would work on a heavily powdercoated mount. What about the pins?

    Doesn't the starter ground also ground the engine?
    "Put out my hand and touched the face of God!"

  4. #4
    Eddie Foy's Avatar
    Join Date
    Dec 2014
    Posts
    2,871
    Post Thanks / Like
    Do I tighten the mount bolts till the mounts bulge slightly?
    "Put out my hand and touched the face of God!"
    Likes Delta Cub liked this post

  5. #5
    www.SkupTech.com mike mcs repair's Avatar
    Join Date
    Aug 2004
    Location
    chugiak AK
    Posts
    9,539
    Post Thanks / Like
    Quote Originally Posted by Eddie Foy View Post
    Do I tighten the mount bolts till the mounts bulge slightly?
    tighten fully, they bottom out on the inner piece(you did put that in right(on bolt))

  6. #6
    www.SkupTech.com mike mcs repair's Avatar
    Join Date
    Aug 2004
    Location
    chugiak AK
    Posts
    9,539
    Post Thanks / Like
    Quote Originally Posted by Eddie Foy View Post
    Doesn't the starter ground also ground the engine?
    if you have that grounded with a wire then you are good... someone already installed a wire previously....

  7. #7
    Eddie Foy's Avatar
    Join Date
    Dec 2014
    Posts
    2,871
    Post Thanks / Like
    Originally the starter was grounded! I planned to do it the same way. What is the purpose of the pins?
    96B5139E-E748-428A-89EB-5271A4371A3D.jpeg
    "Put out my hand and touched the face of God!"

  8. #8
    Eddie Foy's Avatar
    Join Date
    Dec 2014
    Posts
    2,871
    Post Thanks / Like
    Yes. Thanks!

    Is there a torque setting?

    What do the pins do? Are they required? I ask because only two of the mounts had them.



    Quote Originally Posted by mike mcs repair View Post
    tighten fully, they bottom out on the inner piece(you did put that in right(on bolt))
    "Put out my hand and touched the face of God!"

  9. #9
    www.SkupTech.com mike mcs repair's Avatar
    Join Date
    Aug 2004
    Location
    chugiak AK
    Posts
    9,539
    Post Thanks / Like
    Quote Originally Posted by Eddie Foy View Post
    What do the pins do? Are they required? I ask because only two of the mounts had them.
    they keep your engine from falling off... yes important

    use weld rod or whatever for missing ones

    the lock tabs lock into lower bushing, without pin that "could" rotate.......

  10. #10
    hotrod180's Avatar
    Join Date
    May 2008
    Location
    Port Townsend, WA
    Posts
    2,151
    Post Thanks / Like
    Quote Originally Posted by Eddie Foy View Post
    …..Then I can do away with them? I can't see how they would work on a heavily powdercoated mount. ...
    IPC shows them, I would install them.
    Then add supplemental grounding cable if required.
    Scrape powder coating off at isolator mount and at firewall contact points for continuity.
    That's how Cessna designed it.
    That said... I replaced the engine mount on my 53 a couple years ago,
    when I was bolting on the ground straps from the oil pan to the engine mount,
    I realized I'd forgot to scrape the paint off the firewall contact points.
    So added an engine-to-firewall cable just for insurance.
    So
    Cessna Skywagon-- accept no substitute!

  11. #11
    www.SkupTech.com mike mcs repair's Avatar
    Join Date
    Aug 2004
    Location
    chugiak AK
    Posts
    9,539
    Post Thanks / Like
    Quote Originally Posted by hotrod180 View Post
    IPC shows them, I would install them.
    leave them off, you are replacing with a better performing idea, or in your case someone already figured out they were worthless...

  12. #12
    Eddie Foy's Avatar
    Join Date
    Dec 2014
    Posts
    2,871
    Post Thanks / Like
    I agree. The starter and alternator are grounded to the firewall.


    Quote Originally Posted by mike mcs repair View Post
    leave them off, you are replacing with a better performing idea, or in your case someone already figured out they were worthless...
    "Put out my hand and touched the face of God!"
    Likes mike mcs repair liked this post

  13. #13
    Tom3holer's Avatar
    Join Date
    May 2012
    Location
    Cape Cod
    Posts
    420
    Post Thanks / Like
    I was having sluggish cranking issues with my newly acquired 185 a couple of years back. It had a newer engine with a Seaplanes West mount.
    I couldn't see any obvious grounding between the engine and the mount so called Seaplanes West and yep there is no grounding between the mount and engine.
    Added a strap at the starter motor mount and big difference in cranking.
    Likes wireweinie liked this post

  14. #14
    skywagon8a's Avatar
    Join Date
    Mar 2008
    Location
    SE Mass
    Posts
    8,257
    Post Thanks / Like
    Quote Originally Posted by Tom3holer View Post
    Added a strap at the starter motor mount and big difference in cranking.
    AD79-25-7 ​ Those grounding straps are inadequate and prone to breaking, thus the AD note.
    N1PA
    Thanks wireweinie thanked for this post
    Likes mike mcs repair liked this post

  15. #15
    hotrod180's Avatar
    Join Date
    May 2008
    Location
    Port Townsend, WA
    Posts
    2,151
    Post Thanks / Like
    rgl.faa.gov/Regulatory_and_Guidance_Library/rgad.nsf/0/2B49290E9B9D8414862569A40052B07C?OpenDocument&High light=79-25-07

    Apparently only applicable to alternator-equipped C180's --
    and maybe just the 60 amp alternator, not the original 52 amp model.
    Another good reason to just stay with the generator!
    Cessna Skywagon-- accept no substitute!

  16. #16
    skywagon8a's Avatar
    Join Date
    Mar 2008
    Location
    SE Mass
    Posts
    8,257
    Post Thanks / Like
    Regardless whether the starter was mentioned or not, the AD was applicable to Tom3holer's airplane. And the reason for it would be applicable to starters as well as alternators. He did not have one installed. Applies to:CESSNA Models 180, 182/F182, 185, A185, 188, A188, P206, U206, TU206, 207, T207, 210, T210, P210N Series Airplanes
    N1PA
    Likes mike mcs repair liked this post

  17. #17
    Tom3holer's Avatar
    Join Date
    May 2012
    Location
    Cape Cod
    Posts
    420
    Post Thanks / Like
    Just read this and no it does not have that connection from the ground post of the Alt and the engine.
    It is at MHT for the annual and I will mention it to the guys. Will be up there most of next week as were installing a Trio A/p also.

  18. #18
    PerryB's Avatar
    Join Date
    Aug 2007
    Location
    Northern Calif.
    Posts
    1,594
    Post Thanks / Like
    Quote Originally Posted by Tom3holer View Post
    I was having sluggish cranking issues with my newly acquired 185 a couple of years back. It had a newer engine with a Seaplanes West mount.
    I couldn't see any obvious grounding between the engine and the mount so called Seaplanes West and yep there is no grounding between the mount and engine.
    Added a strap at the starter motor mount and big difference in cranking.
    When you think of what the ground path(s) must've been prior to adding the cable/strap, it's kinda concerning. How many amps can a vernier cable carry....?
    After Monday and Tuesday, even the calendar says WTF !
    Likes mike mcs repair, wireweinie liked this post

  19. #19
    www.SkupTech.com mike mcs repair's Avatar
    Join Date
    Aug 2004
    Location
    chugiak AK
    Posts
    9,539
    Post Thanks / Like
    Quote Originally Posted by PerryB View Post
    When you think of what the ground path(s) must've been prior to adding the cable/strap, it's kinda concerning. How many amps can a vernier cable carry....?
    I made the primer line glow red once


    Sent from my iPhone using SuperCub.Org mobile app

  20. #20
    www.SkupTech.com mike mcs repair's Avatar
    Join Date
    Aug 2004
    Location
    chugiak AK
    Posts
    9,539
    Post Thanks / Like
    Quote Originally Posted by PerryB View Post
    When you think of what the ground path(s) must've been prior to adding the cable/strap, it's kinda concerning. How many amps can a vernier cable carry....?
    Seen more than one tach cable with the plastic melting off sheath


    Sent from my iPhone using SuperCub.Org mobile app

  21. #21
    PerryB's Avatar
    Join Date
    Aug 2007
    Location
    Northern Calif.
    Posts
    1,594
    Post Thanks / Like
    Quote Originally Posted by mike mcs repair View Post
    I made the primer line glow red once


    Sent from my iPhone using SuperCub.Org mobile app
    Oh, that's a happy thought... What could possibly go wrong ??
    After Monday and Tuesday, even the calendar says WTF !
    Likes mike mcs repair liked this post

  22. #22
    wireweinie's Avatar
    Join Date
    Aug 2013
    Location
    Palmer, AK
    Posts
    1,929
    Post Thanks / Like
    I don't understand why there would be an argument against installing a ground strap from the engine to the airframe. Many of us have seen the smoke and/or repaired the mess left over when that strap was not installed. Saying that it should not be installed because it's not listed in a AD or service bulletin or that the aluminum bridges should be relied on just because 'it's in the parts book' is foolish and actually dangerous.
    If you believe in the stock aluminum bridges, go ahead and install them. Then track there condition as the aircraft is operated. I've seen the crack in as little as 20-25 hours. I have seen ground straps break from time to time but it's usually from human error, such as to tight or poor workmanship.
    You have a CAR 3 aircraft. You have an improvement which is a minor mod by anyone's interpretation. Install the ground strap already! And if the aluminum bridges are already there, just ignore them. Chances are, they're already broken and if not soon will be. Even when broken they won't cause further damage.

    Web
    Life's tough . . . wear a cup.
    Likes mike mcs repair, skywagon8a liked this post

  23. #23

    Join Date
    Jul 2010
    Location
    Elizabeth, WV
    Posts
    454
    Post Thanks / Like
    Quote Originally Posted by mike mcs repair View Post
    I made the primer line glow red once


    Sent from my iPhone using SuperCub.Org mobile app
    There is a guy who anneals his primer line every 8-10 years to keep it from cracking. I didn't think anyone else would do that.
    You can't get there from here. You have to go over yonder and start from there.
    Likes mike mcs repair liked this post

  24. #24
    skywagon8a's Avatar
    Join Date
    Mar 2008
    Location
    SE Mass
    Posts
    8,257
    Post Thanks / Like
    Since we are talking Bonding Strap it should be mentioned that this applies to ALL types of airplanes whether there is a bulletin of some sort or not. I used to own a Lake LA-4. The grounding strap was attached to the aluminum oil cooler bracket which was riveted to the steel engine mount by about half a dozen AN470-3 (1/8") rivets. The aluminum oil cooler bracket was insulated from the steel engine mount with some zinc chromatic tape. Thus the ground path was only through the rivets. I was having the same issues with starting that Tom described in post #13 until I relocated the ground strap to the steel engine mount.

    Everyone should check his plane no matter what type it is, to ensure that there is a good ground strap between the engine crankcase and the main ground source of the airframe. If your belt driven alternator/generator has a rubber mounting bushing, it too should have a means to ground it to the airframe.
    N1PA

  25. #25
    wireweinie's Avatar
    Join Date
    Aug 2013
    Location
    Palmer, AK
    Posts
    1,929
    Post Thanks / Like
    The ideal ground path for any item mounted on the engine should be from the crank case to the air frame. Then from the air frame to the ground terminal on the battery. This path should be as direct as possible and avoid riveted or bolted connections. In a Cub it should go from the crank case to the steel tubing. As the tubing is welded together it provides a direct, low resistance path to the point where the battery ground lead is attached. In a Cessna, good luck, lol. Avoiding riveted joints in the ground path is almost impossible. In that case, keep it as direct as possible. The ground path crossing a couple of joints is better than crossing five or six. Honestly, the best ground path for the starter & alternator in a Cessna is to mount the battery on the firewall and connecting the battery ground strap directly to the engine. This also allows you to use a much smaller ground strap from the crank case to the air frame as that strap only needs to support lights, radios, etc.

    Web
    Life's tough . . . wear a cup.
    Likes mike mcs repair liked this post

  26. #26
    www.SkupTech.com mike mcs repair's Avatar
    Join Date
    Aug 2004
    Location
    chugiak AK
    Posts
    9,539
    Post Thanks / Like
    now with the small batteries mounted up front(inside firewall), I run my main ground to the engine case, with a smaller wire(same size as buss) going to the airframe & avionics ground plane(mounting shelf for all the boxes) from same connector on ground at battery... lights are all shielded wire with their own grounds....

  27. #27

    Join Date
    Mar 2018
    Posts
    124
    Post Thanks / Like
    If there is any worry about the rules by your particular Fed, just install the expensive aluminum straps. Then install a nice clean bonding (or grounding,- whatever) connection as described multiple times here. Then you can be sure to both avoid arguments with the authorities and still enjoy a good positive connection to your battery.

  28. #28
    CamTom12's Avatar
    Join Date
    Jul 2015
    Location
    Huntsville, AL
    Posts
    430
    Post Thanks / Like
    I’m experimental, so I don’t know if this would fly on a certificated plane, but I added a braided grounding cable from the engine case to the firewall. I ran a bolt through the firewall and added another grounding cable to my battery ground.
    Likes mike mcs repair liked this post

Similar Threads

  1. Metal bonding?
    By Farmboy in forum Experimental Cubs
    Replies: 26
    Last Post: 01-12-2018, 07:28 PM
  2. Bonding new aluminum door skins
    By d.grimm in forum Everything Else (formerly:My Other Plane Is A....)
    Replies: 4
    Last Post: 12-27-2014, 09:51 PM
  3. Ground Strap?
    By bob turner in forum Cafe Supercub
    Replies: 5
    Last Post: 07-25-2013, 01:53 PM
  4. Sheepskin shoulder strap protectors
    By WindOnHisNose in forum Cafe Supercub
    Replies: 38
    Last Post: 05-23-2013, 11:04 PM
  5. J3 wing tank strap material
    By Dan Gervae in forum Everything Else (formerly:My Other Plane Is A....)
    Replies: 1
    Last Post: 09-07-2011, 01:16 PM

Bookmarks

Bookmarks

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •