Magnecor Race Wires: Mitsubishi twin cam technical bulletin

Technical Bulletin 069801, dated 06/98

Dodge Colt Turbo
Eagle Talon, 2000GTX
Hyundai Sonata, Elantra, Lantra
Mitsubishi Colt, Eclipse, Galant, Lancer, Mirage etc.
Plymouth Laser

... and many other vehicles with Mitsubishi 4 cylinder 16-valve DOHC engines

We have recently identified a serious problem suffered by the above engine, emanating from poor design of the factory spark plug wire connectors, together with the valve cover assembly and its gasket. In our opinion, this problem is so serious, that many of the driveablility and spark plug wire problems that owners encounter, including engine hesitation and misses, can be directly attributed to moisture and oil accumulating in the deep un-drained wells in which the spark plugs are situated. The problem occurs no matter what brand of spark plug wires are used.

Like most engines with spark plugs situated in deep un-drained wells in the cylinder head, these engines are prone to water accumulating in the spark plug wells where there is no air-flow. Moisture usually forms (as the engine cools down) in the wells as a result of humid air (and water) being drawn through the vent holes in the top seals of the wires' extended connectors that fit onto the spark plugs. Generally, most of the condensation formed in the wells evaporates back out through the same connector vent holes next time the engine heats up — although this evaporation process often fails to perform satisfactorily if the car's engine is washed, or the car is driven in areas where high humidity and/or rainfall is constant. Little, if any, evaporation will ever take place if oil is present.

Unfortunately, these engines also suffer from chronic oil leaks from the valve cover gasket — more so on high mileage engines where crankcase pressure is higher, and the leaking oil easily finds its way into the deep spark plug wells where it mixes with the forming moisture to prevent it from evaporating. Hot engine oil can also cause the bottom seals on original style connector’s to swell .

If a spark plug and the bottom end of a connector gets wet from water splashing around inside a well, sparks will track down between the spark plug porcelain and the connector’s bottom seal to ground out into the outside moisture in preference to firing a hard to fire spark plug gap whenever the engine is under extreme load, particularly if the gap has become excessively worn or has been adjusted wider than the original gap. This problem never occurs unless conductive moisture is present around a spark plug and a spark plug wire connector.

Just ONE wet connector or spark plug can cause the engine to hesitate or miss when under load, and often, just fitting another set of wires (new or old) will temporarily solve the problem — until any one of the connectors fitted to those wires again becomes affected by the water and/or engine oil in a well. If the car is driven for long periods in this condition, an arc-hole will develop around the bottom of a connector, and whenever it gets wet, arcing to the water will immediately occur.

A spark plug that is often recommended for this engine, particularly modified turbocharged engines, is the NGK BPR7ES, which should be gapped at 0.028" and is colder than standard spark plugs.

Like any high performance engine — THIS ENGINE NEEDS REGULAR SERVICE AND PREVENTIVE MAINTENANCE — otherwise it will not perform satisfactorily!! Regular servicing and preventive maintenance should always include:

1. Careful examination of the spark plugs to ensure gaps have not widened to where the engine’s overall performance (particularly under load) will be compromised by the inability of the ignition system to provide sufficient voltage to fire excessive gaps. Also, excessive gaps can cause the full spark carried by Magnecor Race Wires to find an easier path to ground via a wet spark plug connector or spark plug in preference to firing across excessive gaps under load. Never use re-gapped worn spark plugs in this engine.

2. Careful examination of each connector and spark plug well for evidence of moisture accumulation and/or oil contamination. Never expect a 40,000 + volts connector to ever function satisfactorily if covered in moisture and/or engine oil. Moisture accumulation in wells in the early stages is not always obvious to the untrained eye, and for that reason we recommend owners accept that water will inevitably accumulate from time to time — more so if you drive in rainy or humid areas, or live near the sea where heavy condensation forms over the engine (usually at night as the engine cools down).

3. Rectification of oil leaks. All too often we see connectors showing they were used in spark plug wells filling up with engine oil that leaked from the valve cover. Unless it was replaced recently, it’s never a good idea to just tighten a leaking valve cover gasket, as the extra pressure on the gasket can terminally damage (crush and split) it and make a bad situation even worse.

IMPORTANT: Whenever you wash oil from this engine, water needs to be cleared from spark plug wells with compressed air or a workshop vacuum cleaner. Water will evaporate from connectors removed from the spark plugs and left to dry outside of the wells.

Please remember Magnecor Race Wires are primarily for use on race engines needing full coil current to be conducted via the ignition wires to the spark plugs. No race engine will ever be run with old excessively worn spark plugs, or water and/or oil in the spark plug wells. Factory wires use carbon conductors to reduce spark current as a method to provide suppression and are not affected as quickly as race wires (conducting full coil current) by water and oil in spark plug wells — although the engine will lose power!

If your engine develops a miss or hesitation, it is important you act immediately. Before anything else, you should carefully remove the connectors from all spark plugs. Closely examine each connector at the end which fits over the spark plug. If any connector is covered in oil, you will need to clean off the oil with a suitable solvent (do not soak connector in solvent). Water is harder to see, as it usually evaporates off the connector when it’s pulled out of the well.

If you act immediately, cleaning out the spark plug wells and leaving the connectors outside of the spark plug well to dry will usually solve the problem. However, if the problem has been coming and going for some time, and has suddenly got worse, check carefully for a microscopically small arc-hole on the connector’s outside at about where the metal terminal (inside the connector) ends — sometimes, there’s traces of white around an arc-hole if no oil is present. If you do find an arc-hole, you need to either replace the wire or repair the connector, as arcing will occur whenever the engine is under load and the connector is wet. To repair a connector, thoroughly clean it with a solvent and use RTV silicone adhesive to fill the arc-hole (see below).

On street car sets, Magnecor currently uses better designed connectors which are more easily repaired than the OE design if an arc-hole is burnt through a connector. However, better connectors will not overcome the problem caused by water and/or oil accumulating in spark plug wells.

With proper attention, an extremely long service life can be expected from a set of Magnecor Race Wires — as long as care is taken to keep the spark plug connectors dry and free from leaking oil.

Magnecor’s warranty, like all other wire manufacturers' warranties, does not cover problems caused by engine design, inadequate engine servicing, incorrect fitting of wires, modifications of wires and damage. However, if your Magnecor wires become damaged by incorrect fitting and water and/or oil accumulation problems, we can usually repair wires sent to us. Individual wires are always available as spare parts.

WARNING

In an endeavor to overcome the water in the spark well problem, we often see connectors which have been covered in silicone grease, and often a frustrated owner will stuff the connectors' spark plug opening with so much silicone grease, there's no room for the spark plug. Although silicone grease can help if used sparingly on the inside of the bottom seal only, it does not overcome the fact that water will always find its way into the spark plug hole, and it will always end up wetting the spark plug and connector (even if it's covered with silicone grease). Stuffing connector spark plug holes with too much grease can cause the connectors to pop off spark plugs, and the terminals inside to slip off the ignition cable if connectors are removed by pulling to one side.

(see photographs, below).

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.
For more service and technical FAQs look at the How-To section at Club DSM or the Visual FAQ..

Spark plug connector shown above has been damaged by water inside a spark plug well. Red arrow points to an arc-hole burnt by the spark arcing through the plastic tube to reach the water on the outside of the tube at times when the spark finds it easier to ground out to the water than it is to fire across a widened spark plug gap (from wear or adjustment) when the engine is under load.

An arc-hole in the plastic tube can be hard to find, and a magnifier will help (it is not always as obvious as the example shown at left) — but usually it will appear at the location marked by the red arrow (anywhere around the plastic tube). The example connector shown also had oil all over it from a leaking valve cover gasket, and the car had been driven a great number of miles in this condition with the engine misfiring each time the connector became wet and arcing occurred.

Hot engine oil can also cause the bottom seal to swell.

Click here for another photograph from a Ford Taurus SHO, demonstrating other problems mentioned above

Example of latest version all silicone rubber one piece spark plug connector shown above (also covered in engine oil) can withstand more abuse from water and oil than the OE style connector, although too much water and/or oil in spark plug well will also cause this style connector to become damaged over time. If water is not removed from well soon after an engine miss is first noticed, an arc-hole can also be burned by the spark wanting to ground out to the water on the outside of this connector in preference to firing across a widened spark plug gap (from wear or adjustment) when the engine is under load. Red arrow indicates area where an arc-hole will most likely be found (anywhere around the connector's shaft).

Fortunately, an arc-hole in this style connector can sometimes be repaired with RTV silicone adhesive. Clean the connector with a solvent, and open up the hole with a small nail or paperclip so that the RTV can be pushed into and around it. Allow RTV to set for about 12 hours. Remove all water and oil from spark plug well before re-installing. Also check condition of spark plugs.

Click here for another photograph from a Ford Taurus SHO, demonstrating other problems mentioned above