Braided ground strap material

[Draker]

Did some reading on VAF and decided to go with braided material for engine to firewall grounding. Is there any guide to the right size of this braid? I have a standard SkyTec starter that came with the Lycoming engine, and am using 4AWG wires for the battery and starter positive current, and I have extra 4AWG crimp lugs I plan to use with the braid. I see Spruce sells a number of sizes, but not sure which one is right for this application. Also B&C offers this material, at significant extra cost. Any suggestions? I plan to double-up the braid as some builders have recommended.

 

[rv8ch]

I used two of these, and they say it's the equivalent of #2AWG. My starter wire is also #2 - used Eric's "super-2 CCA" cable. http://www.periheliondesign.com/fatwires.htm



I imagine that 2x #4AWG will be fine if that's what you are using for your battery, assuming that the length of the cable is not too long. Mine were about 12".

 

[Dorfie]

I used similar to these. Cut some ends off and crimped required size ends as needed. I used 4.

https://www.delcity.net/store/Groun...erm=4576923312717638&utm_content=All Products

 

[PhatRV]

I am using the 1/2 inch braided strap for my engine grounding wire. I crimped the copper lugs to make the connection to the vacuum pump pad and the firewall.

I've seen small grounding wire in flying airplane and automobile. I just happen to have the 1/2" braided strap around.

 

[fl-mike]

I am using the 1/2 inch braided strap for my engine grounding wire. I crimped the copper lugs to make the connection to the vacuum pump pad and the firewall.

I've seen small grounding wire in flying airplane and automobile. I just happen to have the 1/2" braided strap around.

that is on the small side if you look at cross sectional area compared to the starter wire. A 1" strap would be about the minimum for starter ground return currents. Two would be better.

 

[gasman]

NAPA Autoparts...... https://www.napaonline.com/en/searc...ap&scene=partTypesScene3&fullyQualified=false

 

[fl-mike]

Did some reading on VAF and decided to go with braided material for engine to firewall grounding. Is there any guide to the right size of this braid? I have a standard SkyTec starter that came with the Lycoming engine, and am using 4AWG wires for the battery and starter positive current, and I have extra 4AWG crimp lugs I plan to use with the braid. I see Spruce sells a number of sizes, but not sure which one is right for this application. Also B&C offers this material, at significant extra cost. Any suggestions? I plan to double-up the braid as some builders have recommended.

https://www.gacopper.com/Braid.html

gives you a equivalent AWG and a "current rating" that should help size the strap.

 

[PilotjohnS]

short Braids

I think if you keep the braid short, it helps with the voltage drop.
Also for surge currents, short braids work better. For longer runs, regular wire I think is better.

 

[Carl Froehlich]

Why not use the same gauge wire to provide the engine ground as the wire to the starter?

#4 or #2 welding wire is very flexible and durable - I use it for starter power and engine ground. I ground the engine on the nice ground lug on the starter - the thing that takes all the current.

Carl

 

[Carlos151]

+1 for #2 wire ground

Why not use the same gauge wire to provide the engine ground as the wire to the starter?

#4 or #2 welding wire is very flexible and durable - I use it for starter power and engine ground. I ground the engine on the nice ground lug on the starter - the thing that takes all the current.

Carl

Did exactly what Carl talks about along with an additional braided ground wire mounted on the back side of the motor. Eliminates any chance of the ground return going anywhere else.

 

[larryMar]

I also used welding cable for ground. I did find after a couple of years I would have to pull it off and "flex" the cable aggressively, as occasionally the starter would not turn or click. It was almost like the battery was dead. My cable length was about 12" or less. After the cable was flexed, it would be fine again for a year.... corrosion...?

 

[Carl Froehlich]

I also used welding cable for ground. I did find after a couple of years I would have to pull it off and "flex" the cable aggressively, as occasionally the starter would not turn or click. It was almost like the battery was dead. My cable length was about 12" or less. After the cable was flexed, it would be fine again for a year.... corrosion...?

I would suspect a bad terminal crimp.
Carl

 

[rapid_ascent]

Mike,

Thanks for that link. Not sure which path I'm going to take yet but if I need to make a custom braid that vendor would be helpful.

 

[fl-mike]

Not too hard to make your own.
Couple options:

1. Terminate the braid in a crimp lug and use the crimper at your local West Marine (I have a big-a$$ T&B compression crimper and dies, so I drag that out every few years)

2. Squish an appropriate size copper pipe or brass tube over the end of the braid and solder (rosin flux) the braid inside. Drill or punch the hole. Clean off the flux. A rivet squeezer and flush dies can provide the squish.

3. Use (as others have suggested) similar cable as the supply and crimp on a lug (see #1).

 

[lr172]

Did some reading on VAF and decided to go with braided material for engine to firewall grounding. Is there any guide to the right size of this braid? I have a standard SkyTec starter that came with the Lycoming engine, and am using 4AWG wires for the battery and starter positive current, and I have extra 4AWG crimp lugs I plan to use with the braid. I see Spruce sells a number of sizes, but not sure which one is right for this application. Also B&C offers this material, at significant extra cost. Any suggestions? I plan to double-up the braid as some builders have recommended.

Bigger is better in this regard, but technically the ground strap does not need to be any bigger than the starter feed, so 4 gauge in your case. You should be able to buy pre-made ground straps in #2 of various legnths for under $10.

 

[Southern Pete]

Don't scrimp on earth straps, can result in significant starting problems. A poor earth connection can also discharge a fresh battery pretty quickly.

 

[PilotjohnS]

Improvement

I am using the 1/2 inch braided strap for my engine grounding wire. I crimped the copper lugs to make the connection to the vacuum pump pad and the firewall.

I've seen small grounding wire in flying airplane and automobile. I just happen to have the 1/2" braided strap around.

PhatRV,
This ground strap can be improved.
The strap is attached to the cover plate. The current needs to either flow thru the bolt, or thru the gaskets to get to the braid. Most Lycomings have a tapped boss near the engine mount; I would think it is better to attach the strap there so the lug can make direct contact with the engine case.

 

[jcarne]

I used the stuff from B&C. I also doubled it up. Here are some pics of how I attached it to the engine. It looks like it is touching the prop gov. oil line but it's actually about an inch or so away. Make sure to remove the engine paint too.