Need 4 Speed - Magnecor Tech Info

It has come to our attention that a problem exists with spark plug gap settings on some 1996 and later Saturn engines.

For whatever reason, the original factory specified spark plug gap for many 1996 models (specified on the car's emissions sticker, in the owner's manuals and in service manuals) is 0.060 inch (1.5 mm). However, Saturn dealers, and Saturn themselves, all recommend the 0.060 inch (1.5 mm) specified gap should be 0.040 inch (1.0 mm) to avoid performance and driveability problems. It is important to note Saturn recommends the original spark plugs should not be re-gapped — new spark plugs (P/N 21024004 - SOHC engine, or P/N 21024005 - DOHC engine) should be installed with gaps set to 0.40 inch (1.0mm).

Also, to reflect this change, the Federal or California Emissions Label needs be changed to a new one that shows the correct spark plug gap. For more information you should refer to Saturn Technical Information Bulletin No. 96-T-25, April 1996 (which will be available from your Saturn dealer).

If spark plug gaps on a Saturn (or any engine) are too large, performance and driveability problems, including hard starting, an engine miss and/or hesitation under load, will occur and appear similar to problems caused by badly worn high-mileage spark plugs. Also, spark plugs with excessive gaps will wear out prematurely as a result of accelerated tip erosion. With the original ignition, the coil energy output may not be sufficient to reliably jump the 0.060 inch (1.5 mm) gaps, or larger with prolonged use, and with a high-output ignition installed, at times the spark energy will track down the coating formed from combustion on the porcelain surrounding the center electrode in preference to crossing the widened spark plug gaps.

This spark plug was removed from a 1996 DOHC Saturn engine with driveability problems caused by the failure of this spark plug. The burnt area on the porcelain insulator shows cracking, and arcing has been occurring from the cracks to moisture (see rust deposit) between the bottom of spark plug wire connector and plug body. A spark plug in this condition will not function correctly, and neither will your ignition system!

SOLUTION: Replace sparks plugs at recommended intervals. Do not run excessive gaps (due to wear or adjustment).

If excessively gapped spark plugs are not changed at the time Magnecor Race Wires are fitted, driveability problems on street vehicles, which may not have been as noticeable when the factory carbon conductor wires were fitted, may develop as a result of the additional spark energy conducted by Magnecor Race Wires further eroding the wide gaps, and sometimes a leaning-out effect under a trailing throttle may be perceived.

We might add that an engine management system designed to run with 0.060 inch (1.5 mm) gap may cause the engine in some street cars to miss occasionally at idle and may cause an exhaust emission setting change if the gaps are set at 0.040 inch (1.0 mm) — since larger spark plug gaps can improve idling smoothness (and decrease emissions). For this reason, the new type spark plugs recommended by Saturn should be used.

Magnecor does not profess to be a Saturn specialist, therefore, if you need further advice or confirmation of the above, we recommend you contact your local Saturn dealer or the Saturn Corporation. For the time being, Magnecor recommends you take the advice of Saturn and their dealers and ensure your spark plugs are replaced with the Saturn-recommended ones, with gaps set to 0.040 inch (1.0 mm) — if you have not already done so!

Also, it is important to route spark plug wires as close as possible to the way the original factory were fitted. In particular, wires for cylinders 1 and 4 should be routed exactly like the factory wires, as the engine management system on 1996 and later Saturn engines relies on the proximity of these 2 wires to function correctly.