MSD Ignition Upgrade

Nov. 24, 2014 By Jim Brightly, KF7SCT
More power and a faster response is a huge plus while rock climbing.

MSD makes a high-end, high-performance distributor for almost every modern engine still in use, be it an off-roader, a hot rod, or a stocker; if it uses a distributor. Using a Chevy V8—arguably the most popular conversion engine in use today—as the example, we pulled the OEM distributor and installed an MSD unit with selectable vacuum advance to show how it’s done.

This particular engine had a history of overheating and pinging under high-RPM loads—a common plight for engine conversions—so we were trying different solutions. We’d gone back to a mechanical, high-flow fan and custom-made radiator fan shroud, which pretty much cured the high-speed heating problem, but the engine was still pinging on long freeway hill climbs. Because it didn’t ping around town or on the trails, we decided that the OEM distributor—even though it was timed correctly at idle—was advancing the ignition too far at higher RPM on the freeways.

The OEM General Motors distributor does not have a selectable vacuum advance degree, whereas the MSD distributor (PN MSD8362; $150) does. And we included MSD ignition cables (PN MSD31229; $86) to avoid future problems with the old OEM spark plug wires. Known as the Street Fire HEI (high energy ignition) distributor, its components offer a well-designed product that also has a one-year warranty. Knowing the importance of a centrifugal advance in a distributor, we wanted the Street Fire because it has an advance assembly with coated weights and welded weight pins (not just pressed in like other models). Plus the Street Fire has the same drive gear that is used on MSD’s Pro-Billet models. The metallurgy of this gear has been refined for years to perform through the harshest conditions.

Inside the distributor, the ignition module and coil work together to produce a high-energy spark to light the fuel mixture. The high voltage is transferred through a new rotor to the brass terminals of the distributor’s cap and out to the plugs. The Street Fire distributor has an adjustable vacuum advance that helps tune it to each individual engine, with a mechanical and selectable advance up to 21 degrees.

As mentioned earlier, we included an MSD 8.5mm Super Conductor wire set, which has a special helically wound core that has just 40-50 ohms of resistance per foot—but with an RFI suppression equal to a 1,500-ohm wire. In fact, each foot of finished wire features 40 feet of tightly wound copper for superior conductivity. A tough, 8.5mm synthetic/silicone jacket over an extra-heavy glass braid and dielectric insulator keeps the current guided to the plugs. Underneath the high-temperature boots, dual crimp stainless steel terminals feature snap-locks to ensure a secure fit. MSD’s 8.5mm Super Conductor wire sets come available in custom or universal-fit applications.

The MSD box shows the Street Fire and its highlights.

First step is to remove the air cleaner to clear the way to the Chevy’s rear-mounted OEM distributor.

A remote starter switch eases the chore of lining up the No. 1 cylinder.

Watch the timing marks on the crankcase pulley while quickly pressing the remote switch on and off.

Stop bumping the starter when the white line aligns with the timing gauge.

Unscrew and lift off the cap to make sure the rotor is pointing in the proper direction, which is for cylinder No. 1.

The rotor should be pointing in this direction on a Chevy V8.

It takes a special tool or a long time to loosen and remove the distributor’s securing bolt.

Prep the new SF distributor before installation by first removing the cap.

With the cap removed, you’ll also have to remove the rotor.

Check to make sure the centrifugal advance components operate properly.

For the optional spring kit to be installed remove this screw and carefully set it aside.

This is the spring kit. It can be installed in four different positions depending on what maximum advance you want. The instructions include a diagram showing you how to position it properly.

Slide the mounting screw through kit and place it in the distributor.

This is how the kit should be mounted for 8 to 11 degrees of advance (note the letters stamped onto its surface).

The SF distributor is now ready for its rotor and cap to be reinstalled.

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