spark plug gap

[Pipemaster]

what is the gap for the spark plugs supposed to be on a 944?
I'm catching up on maintenance and at least on my MG the plugs have to be gapped perfectly for it to even run. Is it even that important on a 944 or can they just be straight replaced? The ignition is much stronger on these cars than an MG

[v2rocket_aka944]

NGK BPR6ES or the Bosch equivalent, 0.028"

[djnolan]

You always want the gap and the plug torque to be as even as possible to make the engine run smoother with less vibration and for even burning of the fuel. The gap affects the spark energy level and the torque affects the temperature of the plug since the plug cools by passing heat to the head. Torque is around 18 ft lbs.

[Pipemaster]

Originally Posted by djnolan

You always want the gap and the plug torque to be as even as possible to make the engine run smoother with less vibration and for even burning of the fuel. The gap affects the spark energy level and the torque affects the temperature of the plug since the plug cools by passing heat to the head. Torque is around 18 ft lbs.

Well i knew this stuff. It was just the gap that i needed to know. But knowing the torque setting of the plugs is helpful. My intake is going back on tomorrow and i decided to go ahead and replace the plugs as well

[djnolan]

One other thing to note is that many modern platinum or iridium plugs are pregapped and the instructions on the box say not to adjust the gap, even if it is different than the original 944 spec. The center electrode is very delicate and can easily be damaged/ruined by old school gapping methods.

Also the plug torque is usually on the box.

I have had good luck with NGK iridiums and they don't need gapping. I am not expecting the car to last any longer than the plugs.

[beamishnz]

I've had less good luck with the iridium with the 16V cars - they foul up for some reason. I'm a big fan of the Bosch Super copper plugs. WR7DC .7mm for the 944S, WR5DC .7mm for S2, and WR8DS .7mm for the 8V cars. Graphite grease threads and torque to 25-30Nm (18-22 ft lb) .

[v2rocket_aka944]

platinum/iridium is unnecessary on 944 8v or 16v, IMO.

the plugs are way too easy to change on any 944 to need a "long life" plug for 3-4x the price like the rare metals are.

had not heard of torque affecting heat transfer...interesting concept.

[djnolan]

Oh yes, if you want the engine to run smooth then you want the plugs all at the same temp and even torque is essential.

The reason I think long life plugs are such an advantage is every time you take off the plug wire you risk damaging them, so spending an extra $20 on long life plugs means less wear and tear on the wires.