Aerial Acrobatics

RD5T3R · Post by **RD5T3R** » Tue Jan 03, 2006 10:44 pm

Hi Ken
I too swapped out the broken aerial and fitted a bendy one not long ago.
Found the easiest thing to do for ease of access was to remove the spare wheel
and the battery straight off.

The aerial itself is quite short due to the lack of space in the boot so may
well have various brackets attached. Basically undo everything associated
with it and then tape up all the electric plugs except the aerial lead - you
may need them later if you put the old aerial back! Clean the old aerial and
store it.

Undo the new one and play around with the angles until it sits right on the
outside of the car. The kit allows for a soft plastic/rubber boot to sit on
the paint side and a metal base to tighten up against the underneath bodywork
(and provide the direct earth). Do a semi tighten job and test the radio -
yes be VERY careful of the +ve battery terminal shorting to the body through
your spanner - ouch!!

If all ok then tighten up properly. End result is some cables need tucking
away and the space behind the spare is less full - but still not available!!

To be honest it is one of the easiest aerial replacements I have ever had to
do due to the ease of access and lack of holes to poke leads thru before
scratching around behind the dash for the other end to plug it into.

Enjoy

Stu n Viv
RD5T3R

poison · Post by **poison** » Tue Jan 03, 2006 11:40 pm

Be careful when removing the battery terminals with a spanner. If you touch
the car body with the spanner while undoing the terminals it will cause a huge
flash/spark which is not so good.

Gazza

Grant · Post by **Grant** » Wed Jan 04, 2006 12:05 am

To prevent the rather nasty shorting of the battery to ground, remove the
ground terminal and make sure it can't contact the battery negative terminal
by tying it out of the way. You can then work with no fear of shorting to
the body as there is nothing to short. If you are going to remove the
battery anyway, always disconnect the ground wire first. If you can't, use a
spanner with an insulated handle. Just slip some garden hose over the
spanner handle remembering to ensure the end is taped up. A shorted battery
can explode with very severe consequences.
Even a small battery such as in an MX5 can be very dangerous.
Grant.

EricW · Post by **EricW** » Sun Jan 08, 2006 8:49 am

The other one to watch for shorting with spanners etc is the starter
solenoid. I managed to short one across it's terminals with my watch strap
about 30 years ago and still bear the scar.

This solenoid is directly connected to the battery and if you short it you
get the lot, through what ever you short it with. In the case of the Omega
watch strap, it was so much current and heat that it welded all the links
and the catch together, round my wrist, and we could not get the watch off
as it burned almost to the bone. It also completely destroyed my
Speedmaster.

The message for DIY mechanics,----- Watches, wedding rings and other similar
jewellery, which can short electrics or get caught in rotating components
are simply dangerous, make sure you take them off!

Grant · Post by **Grant** » Sun Jan 08, 2006 9:55 am

Very good advice, Eric.
I am so used to removing items sauch as my watch that I forgot to mention
it. Got to be careful working around 2000 a/h batteries in telephone
exchanges. They can vaporise a 12" Crescent in a few parts of a second! It
also tends to drop power to the exchange which would be quite difficult to
explain, especially when you are now in pain fro9m the burn, blind from the
flash, deaf from the noise and extremely embarrased (and probably
unemployed).

Grant.

MadMaz · Post by **MadMaz** » Sun Jan 08, 2006 3:52 pm

Hi Grant

I was amazed to read what you wrote re vaporise a 12" Crescent in a few
parts of a second by shorting a 2,000 amp hours battery like as is at the
telephone exchanges - that's a massive punch those batteries pack.

How many times has this happened and how big and heavy are those batteries?

Re working close to connected batteries, yep, had a similar experience
working on a car with a conducting watch strap in conjunction with a
spanner. I was very, very lucky though with no permanent damage done.
Won't let that happen again.

Cheers
Mark

Grant · Post by **Grant** » Sun Jan 08, 2006 4:38 pm

Fortunately it has never happened to me but I have heard of it happening.
It's very rare as anyone doing this work is made very aware of what can
happen. Also to be able to work on any Telecom premises you have to sit
through annual presentations to reinforce what a small error can do. After
39 years on the job though I have retained some of the warnings!
Don't know what the weight of those cells are. Had to remove one 2 volt cell
from a 50 volt (24 cells) 1200 a/h battery recently. Took two of us just to
slide it out of position to install the replacement. Took about four hours
to do what sounds like a very simple job. They are flooded cells with open
vents so have to be very careful of the acid as well. Very hard on clothes.
12volt 120a/h sealed lead acid are the largest I can manage by myself. They
weigh 50kg. The 180a/h are 75kg so usually need two people to move those
around. You can lift them up but moving sideways and sliding into a mounting
frame is just asking for back problems!
The 2000 a/h 2 volt cell weighs about 140kg when filled. It has a capacity
of about 43 litres of acid. Dimensions are 360mm by 380mm by 600mm high. The
1200 a/h one I recently changed weighed about 89kg and was about 230mm by
370mm by 600mm high. Capacity about 27 litres of acid. The older ones are
made of glass and the more recent ones moulded from some sort of plastic.
They have a very long life with many still testing to full capacity after 25
years in service. To test they are discharged at a 3 hour rate (which is 25%
of capacity). This means a 2000 a/h battery has to be discharged at 500 amps
for 3 hours. For a 50 volt battery that's 25kW of heat to get rid of.
Just been out for a run with some of the local members. Very pleasant warm
run from Blenheim to Pelorus Bridge for lunch and a chat. Fortunately my car
is green as it matched my colour when one member turned up in a nice new
grey NC auto! Lucky beggars. The more I see the NC the more I like the look
of it.

Grant.

kkk · Post by **kkk** » Sun Jan 08, 2006 5:08 pm

Also watch out for your wedding ring. or you may be united by a permanant
weld'

Kenk Whiite MX turbo.

MadMaz · Post by **MadMaz** » Sun Jan 08, 2006 9:44 pm

Hi Grant

Thanks for the very interesting info, especially about the quantities of
acid used, how long the batteries last and the discharge rate of 500 amps
for 3 hours! If the controlled discharge rate is 500 amps I can understand
how one of these batteries would treat a shorted spanner as you had said.
That's some heavy duty current indeed!

Re the NC, I liked them the first time I spotted one - they are very nicely
styled with all the critical "just right" proportions. Nice headlamp
arrangement and tail light set tops off the overall design perfectly.

I think this also applies to the MX5's of all years, series & variations.
Mazda brewed up a winning magic formula right from the start.

Bless their little cotton socks.

Cheers
Mark

From chris.tankard@aderant.com Fri Apr 27 17:40:12 2007
Content-class: urn:content-classes:message
MIME-Version: 1.0
Content-Type: text/plain; charset="us-ascii"
Subject: Power to weight
Date: Mon, 9 Jan 2006 11:16:15 +1300
Thread-Topic: Power to weight
Thread-Index: AcYUoSPvZDbj7JioRvKnmliNnT/5ww==
From: "Chris Tankard" <chris.tankard@aderant.com>
To: "MX5List" <mx5list@mx5club.org.nz>
Precedence: list
Message-ID: <jpe47B.A.I3G.XGZMGB@L733>

Who says that power to weight doesn't matter?

Here is a (large) video 250 RWHP MX5 taking on a host of 911's, M3,
Corvette etc on a track day - Kicks butt

http://videos.streetfire.net/Player.asp ... 49E6-A874-
F9F90A127AD3

Enjoy. BTW the car is owned by Rrrracer off miata.net

C

From chris.tankard@aderant.com Fri Apr 27 17:40:12 2007
Content-class: urn:content-classes:message
MIME-Version: 1.0
Content-Type: text/plain; charset="us-ascii"
Subject: Certification
Date: Mon, 9 Jan 2006 13:57:32 +1300
Thread-Topic: Certification
Thread-Index: AcYUt6vx1w3P2uz4Qn6bSkOifTDnoQ==
From: "Chris Tankard" <chris.tankard@aderant.com>
To: "MX5List" <mx5list@mx5club.org.nz>
Precedence: list
Message-ID: <MuAfX.A.J3G.XGZMGB@L733>

All,

To all the folk who have made changes requiring certification - who did
you get to do the certification work, and what problems did you
encounter?

Also once you had the car certified - who was so helpful to actually
insure it (recommendations welcome)?

C

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