On Wed, 8 May 2002, Chuck Arnold wrote:
> I forgot to mention I have a Pacesetter header into a Monza exhaust --
> considerably better breathing from stock, but not the best. I believe
> there are more horses to be found in tuning the webbers and in perhaps
> the timing.
There's always _more_ power. The trouble is finding it and keeping it!
> A year or so ago someone was looking into a Mallory distibutor for our
> 6s. Anybody do any follow-up on this? Wouldn't be surprised if the
> stock old dizzy is not advancing all that well. Wish I had put an
> Electromotive 3 coil, crank fired electronic ignition in in the first
> place. The $650 seemed steep, but compared to the two crane units and a
> new distributor I would be ahead that way.
Well, I've chimed in on this one before on the Triumphs list, maybe here
too...
Almost every stock dizzy that I take apart has the mechanical advance
plate sticking at least a little bit. Frankly, not too many people read
the maintenance instructions for thier TR6 and lubricate the distributor.
So, there's always some "crud" in there preventing smooth movement.
You can rebuild and re-curve your stock distributor to get a more suitable
advance curve for your driving style, but this isn't cheap. Figure around
$150 - $200 with parts/labor. You might need to add another $50 or so to
get the thing re-curved (if you want to).
The primary advantage to this setup - it's stock. You also get to keep
your distributor drive.
The primary disadvantage - it's Lucas. :-)
The Mallory dual point is a really nice piece of equipment. The dual
points allow for very precise dwell angle all the way to the red zone and
beyond. I use one of these on my race car (at the suggestion of other TR6
racers) and do not run any electronic ignition stuff (like MSD or Crane).
With the dwell set properly (sorry, I can't recall the dwell angle), I run
non-resistor plugs gapped to .040. They work fine.
The primary advantages to this setup - you can recurve it yourself as
there is an adjustable "stop" for max. mechanical advance (it comes out of
the box with 23 degrees of total mechanical advance) and you can get
alternate springs for the counter weights. You can get parts from Summit
or other mail order houses. The quality of the parts is very high.
The primary disadvantage is that it is not stock and that you do not (as
Dick Taylor mentions) have a tach drive. This means you have to convert to
electonic tach or make up a fancy tach drive to run off the cam - this
could be expensive depending on your access to a competent machinist. I
use a cheap Auto Guage $40 electronic tach... I suppose you could convert
your Smith's tach guts to electronic, but this would probably be
expensive.
The Electromotive unit is crank triggered. This means that it is super
precise. The advance curve is settable via switch or pots to get advance
at idle, mid-range and high-range. The processor then extrapolates the
rest of the "curve", so you can get very precise ignition timing advance.
As stated, there are three coil packs - this is a very modern system.
The primairy advantage is that the unit eliminates all the possible
timing ambiguity that a mechanical distributor has - there's no gear-lash,
no end-float issues no "point bounce", no condensor, etc. There is no way
a mechanical distributor can be as precise as the crank-driven system.
Period.
The primary disadvantage is that it is most def. non-stock. It is also not
a "bolt-in" by any stretch. You need to machine the crank driven timing
wheel and then you need to fabricate a bracket to mount the pickup. You
then need to mount the ignition box somewhere (typically in place of the
battery on the firewall) and then build a custom ignition wire set. The
unit is (of course) all electronic, so problem diagnosis is pretty much
swap and test (unless you have a "scope" with you). So you need to carry
at least one spare coil pack and possibly an entire ignition box for
spares. In the words of a certain TR6 racer - there's more shit to break.
Regarding cost, the stock setup is clearly the least expensive. The
Mallory unit requires some machining (you have to adapt your distributor
drive dog to the shaft and this requires a precise machine job to locate
the hole (you only should have .015 of end-float, as I recall))... so you
have to dish out $50 to a machinist. So, figure that you can get one of
these puppies in and working for under $300. You then need a tach, so add
another $40 - $500 depending on your "Taste". The Electromotive setup
_starts_ at around $600 and you'll spend another $100 getting it installed
and then another $40 - $500 for a tach... it's not that cheap.
The answer to which one you use should prbably be made in the presence of
exactly how much performance you need, how you intend to drive the car and
what you budget is.
Oh, and in all cases, toss in another $200 for "tuning" if your real goal
is improving performance - you;'ll need to get on a dyno to figure out if
everything is working together.
> Chuck
regards,
rml
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