Technical Bulletin 089601, dated 8/96. Revised 9/97 and 11/97

Ford Taurus SHO
(3.0 and 3.2 litre 24 valve DOHC V6 engines)

This bulletin is an update of our Technical Bulletin 8/96. We feel we need to further emphasize the importance of preventative measures to overcome problems previously addressed in Bulletin 8/96, particularly as SHO owners will encounter these problems more often as their cars age. We have added some photographs to demonstrate issues raised in this technical bulletin.

The problems, namely the improper fitting of the spark plug wires, and the accumulation of moisture in the spark plug holes, are both directly related to the design of the vehicle and its engine, in that the spark plug wires are extremely difficult to remove and replace, and moisture is allowed to find its way into the deep un-drained spark plug holes, where it accumulates around the spark plug wire connectors and the spark plugs.

In our opinion, after discussions with SHO specialists, these problems should be regarded as very serious by all installers and SHO owners, particularly those who drive their cars in rainy areas or live in humid areas where condensation forms over the engine during the cooling down process (including near the sea, even when there's little rain), as many of the driveablility problems that SHO owners encounter, including hesitation and misfiring will result from failure to take preventative measures to overcome these problems.

Magnecor does not profess to be a SHO specialists, therefore the following mostly contains advice from our SHO specialist installer customers.


Improper fitting of ignition wires to SHOs is a major problem. Installing SHO wires is extremely difficult and surprisingly, we have come across very few technicians who can correctly fit SHO wires. If the wires are fitted without care and not using the correct procedure, driveability problems will result. Therefore, if you doubt your technician's skill in being able to fit SHO wires, we suggest you contact one of the SHO specialists with a reputation for skillful workmanship, a Ford dealer with specific SHO expertise or a SHO club for advice. Specifically, the intake manifold needs to be removed to enable easier fitting of the wires, and to prevent incorrect seating of wires in the valve cover and incorrect connection of spark plug connectors to spark plugs.

Wire sets returned to us for evaluation (both ours and factory wire sets), all had spark plug connectors that indicated either or both incorrect fitting to the engine or that the spark plug connectors had been submerged in water, and sometimes in oil. Wires can also be terminally damaged if the removal procedure is not done correctly. Interestingly, we have seen no problems from customers who have wires fitted by SHO specialists or technicians who are skilled and careful -- which suggests a lot!


SHO 3.0 and 3.2 engines are prone to moisture and oil accumulating over spark plugs and the bottom of ignition wire spark plug connectors situated in deep un-drained holes passing through the engine’s valve covers. This problem becomes worse as the cars age, as it appears more water is allowed to shower over the engine when these cars are driven in the rain. In areas near the sea, heavy condensation forms over the engine during the cooling down process and possibly forms inside the covered spark plug hole. This problem rarely occurs on cars driven in dry areas, and not all spark plug holes will accumulate moisture.

SHO spark plug connector top seals (the rectangular covers that fit over the spark plug tunnels), like the seals on connectors used on many other engines using extended connectors, need to be vented, and appear to do little to cope with the amount of moisture this engine accumulates in its spark plug holes.

Moisture accumulation in un-drained spark plug holes causes sparks be induced into the moisture around the bottom of spark plug connectors, and eventually sparks will also track (inside the connector) from the metal spark plug top, down the outside of the spark plug's porcelain insulator (under the connector's bottom seal) to reach the moisture. At times, spark energy will induce or arc to moisture outside of the spark plug connector in preference to firing a spark plug gap usually because of an excessive (or worn) spark plug gap, failing spark plug or high chamber combustion pressures. Magnecor KV85 Competition ignition wires can sometimes make this problem worse if the connectors are improperly fitted, since our KV85 wires are designed for competition, and therefore more spark energy (compared to factory carbon resistance wires) flows through Magnecor KV85 wires.

Once moisture accumulates, it remains around the spark plugs (it can’t drain away), as generally, the engine's temperature will not entirely evaporate the water because the same vented connector top seal that was ineffective in keeping water and moisture in the air out, is very effective in preventing evaporation of the moisture inside. The problem is further exacerbated if oil is leaking from valve covers and mixing with the moisture (another problem with older cars).

Either or both improper fitting of wires and moisture accumulation will cause spark arcing, which in turn, will cause engine hesitation or misfiring when under load particularly at low speeds. Only one incorrectly fitted or wet connector will cause a noticeable driveability problem. The usual diagnosis by unknowledgeable dealers and/or technicians is "bad wires," and the usual remedy is to replace the wires with a complete new set, which only solves the problem if the wires are fitted correctly. This remedy is only temporary if the moisture (and oil) is not removed from the spark plug holes.

Unfortunately, even when moisture is removed from the spark plug tunnels, owners who encounter this problem will do so at regular intervals (the number of which appears to increase with the age of the car), as in time, moisture will again accumulate, and again a driveability problem will occur. No spark plug wires carrying up to 40,000 volts will function reliably if any part of the connectors are submerged in water (or oil).

Although SHOs are not the only vehicles which suffer driveability problems from moisture accumulating in deep un-drained spark plug holes, SHO owners are disadvantaged by the design of the engine which places the ignition wires in locations that can't be reached without removing and replacing the intake manifold. Therefore, preventive measures to reduce reoccurrence of the problem can become a time-consuming, difficult and costly operation.

Magnecor KV85 Competition ignition wires for SHO engines will rarely, if ever, be terminally damaged by either incorrect fitting or moisture accumulation around the connectors although, like with all other ignition wires, engine hesitation or misfiring will occur.

Often, a skillful technician or knowledgeable owner will establish that only one wire is effected, and the problem is remedied by removal of the effected wire, and simply refitting it to the spark plug or, if moisture is evident, applying silicone grease to the inside of the connector’s bottom seal, and, after removing the water from the hole, carefully refitting the connector to the spark plug.

IMPORTANT: Do not fill a connector with silicone grease, as too much grease will cause the metal terminal inside the connector to be popped off the spark plug top.

If the car has been driven for some time with a driveability problem occurring, and there is evidence of arcing (thin white burn marks) around and just inside a connector’s bottom seal the seal should be replaced (spare seals are available), as silicone grease’s insulating ability will only be effective for a short time over obvious arcing marks (silicone grease tends run down hot spark plug porcelain insulators and out of the seals).

We recommend inspection of the connectors for water and oil at least once a year (preferably before winter), or more often on cars driven in rainy or humid areas. Depending on what is mixed with it, moisture accumulation is usually evidenced by white or brown spots and/or streaks over spark plug wire connector bottom seals, caused by splashing (see photograph, below). However, evidence of clean moisture is not always obvious to the untrained eye therefore we recommend that owners accept that moisture will inevitably accumulate from time to time more so if you drive in rainy areas or live near the sea. The presence of oil will be obvious, and should be cleaned off connectors immediately. Leaking oil can be the result of improper valve cover gasket replacement or aging gaskets. If oil is present, the engine should be inspected by a skilled SHO technician.

SHO specialists recommend use of the correct Motorcraft spark plugs, and so does Magnecor. Some other brand plugs are a fraction taller than Motorcraft plugs for SHOs, and raise spark plug connector sealing sections above the valve covers to allow even more water into the spark plug holes. If you have a need to use another brand or type of spark plug for a street car you should take this problem into account.

Magnecor, like Motorcraft and all other ignition wire manufacturers, does not take responsibility for problems caused by poor engine and body design, inadequate engine servicing or improper fitting of ignition wires. However, if your Magnecor wires are damaged by improper fitting or careless removal and/or engine design related moisture accumulation problems, we can usually repair wires sent to us if you are not able to do so yourself.

Magnecor has made an effort to redesign its wires for SHOs to help reduce the number of times preventative measures against moisture accumulation needs to be taken on street cars. Redesigned wires are now being introduced however, we need to repeat that no spark plug wire connector carrying up to 40,000 volts will function reliably if any part of the connectors are submerged in water (or oil).

Although the SHO engine is an excellent performance engine, one of its shortcomings is poor design of the engine that effects spark plug wire performance. With proper attention, a set of properly fitted Magnecor KV85 Competition ignition wires should last as long as the engine.

Please call your dealer, or Magnecor, if you have any questions. Like before, all Magnecor dealers and installers who purchase our wires for SHOs will be asked to warn SHO owners of these problems, and every wire set pack will continue to include this Technical Bulletin.

Please call your dealer, or Magnecor, if you have any questions.
Please feel free to
contact Magnecor if you have any feedback, we are always interested in your comments.

Rust and oil damaged spark plug connectors
Evidence of moisture accumulation will usually be seen on spark plug connector bottom seal and tube as yellowish- brown (mud and rust) or white sediment (cleaner moisture) remaining on the connectors

Example at
above right shows yellowish-brown sediments.

Example at
above left shows there's oil leaking from valve cover.

Example below shows white sediments.

None of these connectors will function properly when
subjected to these conditions.

Click here for another photograph of a problem wire (from a Mazda twin-cam engine) showing yellowish-brown sediments.

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