Ignition systems can’t really make horsepower, but they can cost you power if you can’t get the air/fuel mixture to burn. High-flowing heads, fuel delivery, cams, pistons, and compression are the main cast members in this mechanized drama. An underperforming ignition system will drag down the entire show. MSD Ignition has built an entire industry around providing support to the other characters in the internal combustion epic, and the introduction of the MSD Ready to Run is sure to bring the HEI crowd to their feet. Read on for a full video and article on the MSD Ready to Run.
HISTORY OF HEI SYSTEMS
The HEI system seen on so many GM factory offerings is not new, and that is part of its drawback in the current performance market. In 1961, Delco, a division of General Motors, announced a new ignition system that eliminated contact points and condensers. Although the first applications were limited to heavy-duty engines, by the early 70’s, the HEI distributor was being offered in selected GM lines of automobiles. In 1975, the HEI ignition system was standard on new GM vehicles.
The HEI acronym stands for High Energy Ignition, and when it debuted on the market, it was just that. HEI provided good energy output for the GM motors during that period where the common engine redline was about 5,500 rpm. It’s biggest advantages were the simplicity of the system. Because the ignition coil was an integral part of the cap, it was easy to install and only required one electrical wire to run. However, in the past 30 years technology has passed by the once-advantageous HEI ignition system.
DRAWBACKS TO THE HEI SYSTEM
The HEI system uses a control module to replace the traditional breaker points setup. The control module was able to provide more spark energy to the spark plugs with better timing control than mechanical breaker point ignitions, which allowed for greater dwell times. Increasing the dwell time enabled the ignition coil to fully charge before releasing its stored energy. Because the coil requires some dwell time to charge before it discharges, there are some mechanical limitations to the system. At higher RPM there is less dwell time between coil discharges, so the coil releases less than maximum energy. History has taught us that with an inductive-type ignition system, higher revs and lower spark energy results in a loss of power or high-end misses. Remember what we said in the opening line? Ignition systems can cost you power if you can’t get the air/fuel mixture to burn.
MSD IGNITION AND THE HEI DISTRIBUTOR
Over the years, one of the more popular conversions has been to replace the stock HEI ignition with an MSD ignition box, coil, and billet distributor. This combination has been very successful on the track and performs reliably on the street, but it does require mounting an external coil and an ignition box in the engine compartment. There is a cost associated with the purchase of multiple components as well. With this MSD setup, the inductive ignition is turned into a capacitive discharge ignition system using a quick-charged, high voltage capacitor that can supply far greater energy to the plug gap than the stock inductive system. No matter what the RPM, each spark is fully juiced.
MSD’s Blaster 2 Coil. High performance upgrade to the stock HEI coil.
For the traditionalist that must have an HEI inductive ignition system, or for the car owner that simply does not want, or doesn’t have room to mount the extra external components, MSD’s new Ready to Run (RTR) distributor will fit the bill. The MSD Ready to Run distributor will even accept a stock GM breaker-point type distributor cap to complete a retro look. This upgrade is quick and easy, starting with removing the bulky stock distributor.
From there it’s simply a matter of installing the new distributor in the engine, connecting three wires and the external coil. MSD ignition systems are well known for making multiple spark discharge (MSD) for a complete burn in the combustion chamber. Our contact at MSD, Todd Ryden, told us that the MSD Ready to Run unit makes multiple sparks below 3,000 RPM, which really helps with a rich mixture in the idle circuit at startup and low RPM; after that it’s a good hot single spark. Todd also explained that the Ready to Run distributor isn’t going to add an instant 20 horsepower. “It will,” he told us, “support power gains better and ties in to other modifications”.
MSD’s new ignition module, built into the distributor, produces a 7.5 amp single spark at the higher RPM range and does not require an MSD ignition control box. Stock HEI modules start dropping sparks around 4,500 RPM. MSD Distributors have been spun over 10,000 RPM without dropping a single spark. For a point of reference, at 7,000 RPM, the ignition system has each cylinder firing 7.2 times a second. Even at that rate of fire, the MSD module produces 50% more current than stock units and delivers better dwell control and a much more precise timing signal.
MSD READY TO RUN DISTRIBUTOR FEATURES:
- Simple and clean installation with only three wires to connect. See Installation Instructions here.
- Powerful built-in module produces a 7.5 amp single spark in high rpm operation.
- Easy-to-adjust mechanical advance with supplied springs and stop bushings.
- Vacuum advance canister for improved economy (vacuum advance feature can be locked out).
- CNC-machined billet aluminum housing and billet aluminum base.
- Maintenance-free magnetic pickup and precision reluctor create stable trigger signals throughout the rpm range.
- Polished steel shaft is QPQ coated (a corrosion resistant and high-wear friction reduction coating) and is guided by a sealed ball bearing.
- Advance plate and weights are made from chrome moly steel and QPQ coated for friction reduction.
- Mechanical advance assembly can be locked out for crank trigger systems.
- Advance weight pins are staked and TIG welded to the plate.
- Nylon pads ensure smooth operation of the advance weights.
- Special oil tract improves lubrication to the distributor and cam gear.
- O-ring seals can be added to modified blocks to improve oil pressure control.
- Supplied with an HEI style distributor cap and rotor (accepts Cap-A-Dapts).
- Does not require an MSD Ignition Control.And for the California Car guys:
- It’s CARB E.O. Approved.
Start your installation by removing the stock HEI distributor in this sequence: Remove the existing distributor cap without disconnecting any of the spark plug wires. Crank the engine until the rotor is aimed at a fixed point on the engine. Note this position by making a mark. Place the distributor cap back on and note which plug wire the rotor is pointing to. MARK THE SPARK PLUG WIRES and remove the distributor cap. Disconnect the wiring from the distributor and loosen the distributor hold down clamp and slide the clamp out of the way. Now you can lift the distributor out of the engine.
Remove the stock HEI distributor by disconnecting the wiring and removing the retainer bolt and plate where the distributor contacts the intake manifold. The old distributor can then be removed from the engine.
Remove the MSD Ready to Run distributor and accessories from the box. Install the new MSD distributor gasket and apply a liberal amount of the supplied lubricant to the distributor gear.
Install the Ready to Run distributor making sure that the rotor comes to rest pointing at the fixed mark. If the distributor will not fully seat with the rotor pointing to the marked position, you may need to rotate the oil pump shaft until the rotor lines up and the distributor fully seats. Position and tighten the hold down clamp onto the distributor. Install the distributor cap and spark plug wires one at a time to ensure correct location. If you’ve been careful in lining up the rotor, you’ll be right in the ballpark for ignition timing, but always check and reset the timing after performing a distributor swap.