November 29, 2023

Installing Heat & Ignition Shields

Installing Heat & Ignition Shields
This is not my engine, but it clearly shows the correct installation of all the heats shields for the plug wires. The Red Rocket now has all these shields installed correctly.

Small block V8s fitted to Corvettes came with a complicated collection of heat and ignition shields. The fiberglass body of the Corvette didn't provide any shielding of radio (RF) frequencies, requiring the use of metal shielding over all the ignition components to prevent RF interference (RF interference can have a severe impact on radio equipment and computer networks).

In addition to the RF shielding there are also heat shields that protect the plug wires from the heat of the exhaust manifolds. These shields sit between the manifold and the plugs and are then covered by the metal RF shielding. V-shaped shields on either side of the block are used to route the 2 front plug wires to the rear of the engine. To further complicate things, the 2 front plug wires must pass through the engine mounts before entering the v-shields!

The image above (which is not the Red Rocket's engine but has the same shielding) clearly shows these heat shields and the v-shield through which the forward plug wires are routed (note that the plug wires pass through the engine mounts). The images below show an L-79 with all the correct shielding, including the RF shielding fitted over the plugs.

The ignition shielding on the Red Rocket was all correct when I purchased it — a previous owner had even had it re-chromed, so it looks better than new — however 2 of the heat shields were missing. I purchased a new set from Zip Corvette and installed them as part of the big 2023 overhaul. I also reinstalled the original v-shields, with the wires for plugs 1, 2, 3 and 4 running through the engine mounts (as they did from the factory). The v-shields had been removed when I installed the urethane engine mounts (it's not possible to fit the v-shields with non-factory engine mounts) however the decision to go back to standard rubber mounts meant that all the heat shields could be put back to standard.

The heat shielding and ignition shielding on the Red Rocket is now 100% present and factory correct.

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