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. We have recently been
testing a new electric pump for FWC and have been running an XR3000 ignition
system with it to evaluate the pump under real world conditions. After a 14
hour day of testing at 1440 RPM, the 1.4 Ohm coil is at less than 115F! 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)).
Upgrade from your Existing IGNITOR
(by Pertronix) 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 a retrofit kit to replace your Pertronix
unit. Your existing coil, cap, rotor, sparkplug wires and sparkplugs are all
compatible with the XR3000 conversion. If you currently have a Ballast
Resistor, it will no longer be needed.
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.
Send your questions or comments to me at firstname.lastname@example.org