converting conventional points ignition to hall-effect in c900

converting conventional points ignition to hall-effect in c900 - possible?

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Craig Ian Dewick - 21 Oct 2004 07:01 GMT

Hi everyone,

I'm looking at figuring out what's involved to replace the conventional
points ignition currently in my 1983 900S (8V, n/a, auto box) with
hall-effect breakerless ignition as featured in C900's imported into
Australia from 1985 and later.

As far as I can tell, the main changes would be:

- replacing the distributor or rebuilding it with retrofit hall-effect
sensor components,

- replacing the coil if the breakerless ignitions require a coil with a
different resistance value,

- installing either the Saab OEM (or 3rd-party) electronic ignition module
or a 3rd-party equivalent,

- wiring it all together.

I have not been able to find any source of parts to retrofit the existing
distributor in my car to become a hall-effect breakerless version, so using
one for a 1985 or later model of 8V engine might be the go. I'm also
researching where hall-effect components can be sourced from in case
something is available via a non-automotive supplier.

The coil issue is pretty simple - either it needs to be replaced with one
that has a different resistance or it can be used as-is. Will determine that
as I go.

The electronic ignition module will be interesting. Apart from the Saab (ie.
Bosch) one and it's 3rd-party copies, there are other ways to go here. I've
seen some commercial units that I found via some googling. Also, there are
projects for breakerless ignition systems which have been featured in
electronics hobby publications both here in Australia and in other
countries, but the big issue with any of this still comes back to dealing
with either replacing or retro-fitting the existing distributor.

I'm a die-hard electronics enthusiast so constructing an electronic ignition
kit is no drama... As any example of something available locally in
Australia, check out the Jaycar Electronics kit # KC-5247 at this link:

http://www1.jaycar.com.au/productView.asp?ID=KC5247&CATID=25&keywords=&SPECIAL=&
form=CAT&ProdCodeOnly=&Keyword1=&Keyword2=&pageNumber=&priceMin=&priceMax=&SUBCA
TID=347

Being in Australia and supportive of our local electronics enthusiast
community, I would prefer to build one of those kits and install it in my
car in preference to buying a commercial solution, unless the commercial
solution comes with the parts to retro-fit the existing distributor and
these part aren't easily obtainable from any other source. 8-)

Regards,

Craig.

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at www.sunshack.org - Operator of Jedi (an APANA Sydney PoP) - please visit
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KeithG - 21 Oct 2004 12:37 GMT

Do not know much about this on Saabs as all of the ones I have worked on
have electronic ignition, but the big deal is getting a place to mount
the hall effect sensor and shutter wheel. If you can find a Saab HE
distributor that bolts up, go that way - It'll be easier. The Bosch
system uses the distributor and an 'amplifier' to trigger the coil. The
only question is if the system uses a resistor in line to the primary
side or not. This should be well documented in a manual (Bentley or
Haynes). Find one in a junkyard and get the whole system including the
portions of the harness necessary.

KeithG

> Hi everyone,
>
[quoted text clipped - 49 lines]
>
> Craig.

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hippo - 21 Oct 2004 23:37 GMT

Craig - sourcing your bits give A-Twins Spares at Girraween a try. No
guarantees but they have some 900 stuff & they're close. Just don't try
ringing at lunchtime!

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Craig's C900 Workshop - 24 Oct 2004 13:00 GMT

>Craig - sourcing your bits give A-Twins Spares at Girraween a try. No
>guarantees but they have some 900 stuff & they're close. Just don't try
>ringing at lunchtime!

Hey John!

I've located a used hall-effect distributor from a 1985 Saab 900 and I will
use that as a starting point to work out what else I need. I'll give the
company you've mentioned a call too and see what they have got available.

On Friday I purchased one of the Jaycar electronic ignition kits that I
mentioned in the original posting and on reading the documentation, it can
be set up to trigger from points set up, from a reluctor set up, and from a
hall-effect set up, so it's quite versatile. When it's built up, the diecast
metal box containing the electronics of the kit can bolt into the same place
that the Bosch hall-effect ignition module is mounted in C900's which had it
fitted from the factory...

I have noticed that the Siemens HKZ-101 hall-effect vane sensors used by
Bosch in the 1980's hall-effect distributors is no longer available, but
I've been exploring data about hall-effect vane sensors from Honeywell and
there are a couple of products there which look promising so I may order
some samples and experiment with the soft-iron 4-slot vane out of a used
hall-effect distributor with a Siemens hall-effect sensor.

From some of the info discovered through Google searches, it seems that the
most suitable Honeywell sensors operate in reverse (electrically) to the
Siemens sensor, but that won't be a problem providing that the triggering
points of the sensor can be kept the same. Adjusting a stock Bosch
hall-effect trigger vane would be easier than making one from scratch. 8-)

Regards,

Craig.

PS. For those in the know, what are the most popular methods of replacing
the seals which go between the rear light clusters and the body metalwork on
a non-hatchback C900? The rear light clusters on my 1983 900S are on their
last legs and are leaking significantly when it rains, letting water into
the boot space. I also need to look at replacing all the door seals as they
are leaking too (the left rear footwell gets very wet when it rains), and
also the internal door skins on the two front doors are looking quite sad.
Can a Saab dealer take care of all this on a C900? Are there any 3rd-party
places (preferably in Australia!) that make seals/gaskets/etc. for light
clusters, doors, windows, etc. on these cars?

Signature

Craig's Saab Page --> http://lios.apana.org.au/~c900 Sydney, NSW Australia
Craig's C900 Workshop -- For all Saab 'Classic' 900 Enthusiasts world-wide!
Website --> http://www.saab900classic.net Email --> c900@lios.apana.org.au
Come and explore our site, and check out our web-forums, mailing list, etc.

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hippo - 25 Oct 2004 07:04 GMT

<PS. For those in the know, what are the most popular methods of replacing
the seals which go between the rear light clusters and the body metalwork
on a non-hatchback C900? The rear light clusters on my 1983 900S are on
their
last legs and are leaking significantly when it rains, letting water into
the boot space.>

Try a skinny bead of black silastic around the mount. You'll only need to
take it off again if you smash a lens, 'cos you can do all the bulbs from
inside the boot.

<I also need to look at replacing all the door seals as
they are leaking too (the left rear footwell gets very wet when it
rains),>

Make sure it's not water coming in from either the left rear wheelwell or
a missing boot / rear floorpan grommet before you start replacing seals.
Pull everything out of the boot after some rain (like now maybe?) and
check. If there's 10cm of water sloshing round in there, it can come in
under braking. I know ...!

<also the internal door skins on the two front doors are looking quite
sad.>

Wreckers. Check the servo on the lhs of the nasty bend coming out of
Katoomba on the way to Medlow Bath. He's had 99s and 900s in there on and
off forever - worth a shot.
Check Parramatta Peestige as well but be prepared to pay top dollar. May
be a bit old for A-Twins. Also worth speaking to Greg at Continental Cars
at Punchbowl (Citroen but used to wreck/repair Saabs & may still have
parts). Motor trimmer or diy with masonite & a matching fabric are your
other two choices. Not cheap options.

<Are there any 3rd-party places (preferably in Australia!) that make
seals/gaskets/etc. for light clusters, doors, windows, etc. on these
cars?>

Probably too small a volume to bother, but as a longshot, see if Savage
Rubber are still in business and speak to someone there. Also worth
speaking to Mildren's. They cleaned out heaps of ancient spares when they
moved years back but you never know ...

<Can a Saab dealer take care of all this on a C900?>

Yes - if parts avail and you throw enough money at them. You joined the
club a while ago didn't you? Try a classified with them. Cheers from the
South Coast

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