From: Gary and Carol Henderson
Date: Fri, 22 Jan 1999 21:17:52 +-1300
Subject: [imps] Earth cables - crimps onto braid NBG.
Hi all
Not really 'calibrating' this time...
Son #3's 1974 Avenger Estate was cranking a little tiredly, OK but not up to what state of battery, temperature etc would lead one to expect.
Did a volt-drop chase - found at each of the crimped-on terminations to the braided earths, almost 0.2 volts drop. (Not counting the lead itself, nor the bolted connection.) With effectively 3 of these grotty connections in series, there was half a volt going up in smoke.... and this is midsummer, with the engine easy to turn over. In winter, there'd be a volt at least.
Managed to clean them up enough to successfully solder them, without dismantling.
Result: Drop now a few millivolts each. Worthwhile increase in enthusiasm from starter.
Basically, crimped connections onto braid are not internally gas-tight. Solder is.
Cheers
GaryH
Date: Fri, 22 Jan 1999 09:03:20 +0000
From: Andrew W. MacFadyen
Subject: [imps] Re: Earth cables - crimps onto braid NBG.
My policy has always been to add extra earth braid(s) in an easily visible position so many cars like the Imp have them tucked away underneath the car where they can't be easily inspected.
Andy M
From: Gary and Carol Henderson
Date: Sat, 23 Jan 1999 00:26:39 +-1300
Subject: [imps] Re: Earth cables - crimps onto braid NBG.
Hi Andy
Point is, these ones looked OK and any ohmmeter would measure them OK.
Only at cranking amps could one measure that there was anything sub-optimum, and where.
By the way, if you go adding serious electronics, then earthing willy-nilly can cause problems.
Cheers
GaryH
From: Nickcleak@aol.com
Date: Sat, 23 Jan 1999 04:35:56 EST
Subject: [imps] Re: Earth cables - crimps onto braid NBG.
You know the reason for crimping and not soldering on automotive wiring ?
It's to prevent vibration cracking the joint ...
Ok to solder it when there is no relative movement on the joint ...
Nick ...
From: Nickcleak@aol.com
Date: Sat, 23 Jan 1999 04:36:00 EST
Subject: [imps] Re: Earth cables - crimps onto braid NBG.
Indeed . my earth strap goes from the battery to the body then on to the timing cover nut above where the exhaust strap fits .. you can see it there ! and it's far more direct .
I can give a Volvo part number if you wish for an excellent lead ..
Nick ...
From: Gary and Carol Henderson
Date: Sun, 24 Jan 1999 01:08:44 +-1300
Subject: [imps] Re: Earth cables - crimps onto braid NBG.
Hi Nick
Good socketed terminals with solder finish gave no trouble.
Crimps are much cheaper!
Cheers
GaryH
From: Nickcleak@aol.com
Date: Sat, 23 Jan 1999 13:52:17 EST
Subject: [imps] Re: Earth cables - crimps onto braid NBG.
oh quite , but there is a hard joint between the solder and flex wire ,
that's where it cracks when flexing , on earth straps to moving engines for example ...
I've seen it in my 27 years experience in the motor trade where people have soldered alternator power feed wires for example and they break off ...!
It causes breakdowns ....
It's one case where it's cheaper and more reliable to crimp !
nick ..
From: Gary and Carol Henderson
Date: Sun, 24 Jan 1999 16:02:44 +-1300
Subject: [imps] Re: Earth cables - crimps onto braid NBG.
Hi Nick
I think we're 98% agreed. Solder to withstand mechanical loading - NEVER.
If you're gonna solder a connection, it must first have full mechanical support.
Same goes for radiator stubs...
If pure crimping is on the agenda, it's best on solid wire (inappropriate for cars!); next best on stranded wire (which can have the strands laid parallel, and be crimped down to a virtual solid) and I would suggest is somewhat suspect for braided cable, which cannot avoid having gaseous voids throughout the crimp. On the subject Avenger, the battery + lead crimp is fine.
Cheers
GaryH
Date: Sun, 24 Jan 1999 13:19:31 +0000
From: Andrew W. MacFadyen
Subject: [imps] Re: Earth cables - crimps onto braid NBG.
I once did an emmergency repair on a stater lead termminal on a racer using a coke can and a small hose clip ! (it worked ! :-))
Heat shrink tubbing especially the type with adhesive on the inside surface is great for adding mechanical strength to joints as it reduces the bending stress concentration.
Andy M