What gap's are you running?
Registered User
Joined: Nov 2001
Posts: 1,213
From: North Vancouver, BC
You lower gap to reduce the chances of detonation by keeing the combustion chamber cooler. You also do it to reduce blowing out the spark on high compression/FI setups.
You raise gap in lower comrpession engines to ensure that the fuel mixture is properly ignited, since the combustion chamber temps need to be higher.
Since you haven't significantly changed your compression, and you haven't added forced induction, I would stick to the stock gap of 0.05, or possibly lean towards Matts suggestion of 0.045.
You raise gap in lower comrpession engines to ensure that the fuel mixture is properly ignited, since the combustion chamber temps need to be higher.
Since you haven't significantly changed your compression, and you haven't added forced induction, I would stick to the stock gap of 0.05, or possibly lean towards Matts suggestion of 0.045.
Thread Starter
Registered User
Joined: Sep 2002
Posts: 1,419
From: Coquitlam, British Columbia
Originally posted by Draco
You lower gap to reduce the chances of detonation by keeing the combustion chamber cooler. You also do it to reduce blowing out the spark on high compression/FI setups.
You raise gap in lower comrpession engines to ensure that the fuel mixture is properly ignited, since the combustion chamber temps need to be higher.
Since you haven't significantly changed your compression, and you haven't added forced induction, I would stick to the stock gap of 0.05, or possibly lean towards Matts suggestion of 0.045.
You lower gap to reduce the chances of detonation by keeing the combustion chamber cooler. You also do it to reduce blowing out the spark on high compression/FI setups.
You raise gap in lower comrpession engines to ensure that the fuel mixture is properly ignited, since the combustion chamber temps need to be higher.
Since you haven't significantly changed your compression, and you haven't added forced induction, I would stick to the stock gap of 0.05, or possibly lean towards Matts suggestion of 0.045.
Registered User
Joined: Mar 2002
Posts: 261
From: Abbotsford, B.C. Canada
Another view on plug gaps...
A little more info on spark plug gaps:
1. The bigger the gap, the more maximum voltage required to start the flow of charge. The quality of the ignition system components determines when misfiring will occur.
2. The bigger the gap, the more area of combustible charge exposed to the spark energy. Generally, the bigger gap you run, the better your chances of good operation.. but, see 1. above
3. With lean the mixtures, more gap is a good way to help ensure adequate ignition of the weak fuel/air charge.
4. The heat of the spark itself has no effect on combustion chamber temperature. A spark plug gets it's heat from the burning of gases in the cylinder, then rejects the excess to the metal/coolant of the cylinder head
5. C/chamber temperature is a result of intake manifold pressure, fuel/air mixture, throttle position, engine RPM, other combustion conditions (eg. fuel anti-knock capabilities) and the engine's cooling system efficiency
That end's today's sermon, er, lesson...
1. The bigger the gap, the more maximum voltage required to start the flow of charge. The quality of the ignition system components determines when misfiring will occur.
2. The bigger the gap, the more area of combustible charge exposed to the spark energy. Generally, the bigger gap you run, the better your chances of good operation.. but, see 1. above
3. With lean the mixtures, more gap is a good way to help ensure adequate ignition of the weak fuel/air charge.
4. The heat of the spark itself has no effect on combustion chamber temperature. A spark plug gets it's heat from the burning of gases in the cylinder, then rejects the excess to the metal/coolant of the cylinder head
5. C/chamber temperature is a result of intake manifold pressure, fuel/air mixture, throttle position, engine RPM, other combustion conditions (eg. fuel anti-knock capabilities) and the engine's cooling system efficiency
That end's today's sermon, er, lesson...