What is Dwell angle and why should I care?
Tired of burned or corroded points, bad condensers, poor starting, idle speed too high--in general, an unreliable ignition system? The Delco and Prestolite distributors supplied with Atomic 4 engines have been the source of countless ignition problems due to the use a conventional breaker point system in a harsh marine environment. Until now, the only means of obtaining reliable operation was constant maintenance and plenty of spare parts.
Well, Electronic Ignition just got a whole lot better
than before with the introduction of the Indigo Electronics "SMART"
Ignition Module. This new kit takes all of the tried and proven aspects of the
original Crane/FAST XR700 based system we have offered for 25 years and
complements them with two new functions
Management and Current Limiting
. The foundation of this new
kit is the Crane/FAST XR3000 Module which was originally designed as a
high performance version of the XR700 for high horsepower, high compression,
high RPM automotive engines. It turns out that those same high performance
features play a key role in solving several ongoing issues that we continue to
have with the Atomic 4. Coil failures due to too much current and overheating
can be eliminated with smaller Dwell angles and by limiting coil current. At
low engine speeds, a minimum Dwell angle is all that is needed to generate a
great spark. At higher RPM, it is desirable to have a larger Dwell angle to
allow the coil to become fully "saturated" for a great spark. And in
all scenarios, coil current is limited to 4.5 amps. Both of these actions do an
amazing job of significantly reducing coil operating temperature and thus
extending coil life while producing an excellent spark. An additional benefit
of the current limiting function is that the feature automatically stops coil
current flow if the engine is not running. NO MORE BURNED UP COILS AND/OR
MODULES IF YOU FORGET TO TURN OFF THE IGNITION SWITCH! This new Module has
another exciting feature in that it can function with many different coils with
NO BALLAST RESISTOR needed! For a superb spark, the kit comes
with a very low 1.4 Ohm primary resistance Coil. This may sound outrageously
low but with the Current Limiting and variable Dwell Angle features, it is pure
genius. With the low primary resistance, there can be a controlled high in-rush
of current which saturates the coil very quickly allowing for a great spark at
all speeds. If for some reason you find that you have to install a different
coil, most any coil will work as long as the primary resistance is less than
about 3.5 Ohms. The higher resistance will not harm any components but the
spark quality will deteriorate somewhat with increasing resistance.
Realistically, the spark with a 2.5 Ohm coil will probably be better than what
you have now.
Introducing the AT-4D and AT-4P Hi-Intensity Electronic Retrofit Kits from Indigo Electronics. These kits have been expressly engineered to upgrade Delco and Prestolite distributors on Atomic 4 engines. Shown below is the complete kit and new breaker plate assembly for the Delco distributor.
At the heart of the system is a Crane Cams/FAST Optical Trigger (LED and Photo Transistor), Shutter, and XR3000 Electronic Ignition Module which control the firing of the ignition coil, replacing the conventional breaker points and condenser. As there are no rubbing parts to wear or electrical contacts making and breaking, the timing never changes once initially set and Dwell Angle is managed by the Ignition Module. Ignition problems are gone forever with only sparkplugs requiring replacement as needed. Additionally, with the Optical Trigger design, the same higher voltage and more crisp spark is generated whether at cranking speed or 3000 RPM. This is especially beneficial when starting and idling, leading to faster, easier starting and reduced idle speed. Other features include:
A Complete Retrofit Package
Easy two-hour installation
Upgrade from your Existing XR700 System - For the
added reliability and peace of mind that the XR3000 Module can bring to
your existing system, give us a call (800-428-8569) for special pricing for
existing customers. To make the Upgrade, it is simply a matter of plugging in
the new XR3000 Module and maybe replacing your existing coil (and
eliminating any Ballast Resistor(s)).
How to distinguish a Delco distributor from a Prestolite? The Delco was applied after about 1969 and is easy to recognize as the distributor cap is held on with two (2) screws. The cap on the earlier Prestolite distributor is held on with two spring clips.