In a message dated 97-06-23 13:13:52 EDT, gardner@lwcomm.com (Scott Gardner)
writes:
> I agree with you in theory, and avoid pigtailing connections myself,
> but have always wondered how big of a difference it really makes.
> After all, the harness plugs and spades in all cars are simple
> metal-to-metal friction fits with no solder, and they seem to do well
> enough. Likewise, as far as I know, all house wiring is pigtailed
> with wire nuts with good results.
>>snip>>
> I guess I should also concede that house wiring isn't subject to the
> vibrational stresses that automotive wiring is, but I was mainly
> discussing resistance, not structural strength. Soldering beats
> pigtailing in that respect, hands down.
Scott:
A couple of differences I would like to point out. First, the connectors used
in a car are not just friction fit, they are "compression-friction" fit. In
other words, when you make the connection, there is a squeezing action of
some sort, that leaves the contact in compression. Same is true of the wire
nuts in house wiring.
The lack of vibration you spoke of is the key to the differences. A house
wiring type wire nut can work loose if subjected to the right kind of
vibration. When that happens, the wires may make little or no contact with
each other. Shrink tubing just doesn't provide the required compression
strength. Over a period of time, the wires can work loose - not to the point
where there is slack, but to the point where there is no longer a good
connection.
Of course, it is possible that a connection made this way will be a good one,
and hold up over time, but it is not a very reliable, predictable way of
doing it. There are many cars on the road, not just LBCs, that have
horrendous electrical repairs, but just keep on running, without a problem,
but it is still a good idea to do it right. There are also many car fires
every year because of faulty wiring. When I bought my TR6, the PO had made a
splice in the main alternator cable by crimping a ring lug on one end,
looping the bare wire of the other end through the ring ONCE, and wrapping
with electrical tape. I can't think of a worst way of doing it, but between
he and I, we drove the car over three years without a problem, before I
discovered the splice and fixed it!
Also, keep in mind the reason for the connectors in an automobile. The ONLY
reason is to simplify the assembly process. By using multible piece wiring
harnesses and plug in connectors, the car can be put together on an assembly
line by semi-skilled workers, in a hurry. In my TR5.0, which I am wiring from
scratch, there are NO connectors except where required to facilitate
replacement, or where that is the only way to make the connection to a
manufactured component, such as gauges, light sockets, etc. All splices are
made with crimped terminals, soldered, and covered with shrink tubing. The
wiring harness is one piece, from the headlights to the fuse/relay/flasher
panel to the dash to the taillights, and is soldered to the connectors at the
fuse/relay/flasher panel. It will be a bear to remove and replace when I
strip the car for final painting and assembly, but I only have to do it once,
and I have the time.
Dan Masters,
Alcoa, TN
'71 TR6---------3000mile/year driver, fully restored
'71 TR6---------undergoing full restoration and Ford 5.0 V8 insertion - see:
http://www.sky.net/~boballen/mg/Masters/
'74 MGBGT---3000mile/year driver, original condition
'68 MGBGT---organ donor for the '74
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