was always wondering which way is the correct way for the spark plug to face for optimal spark


Modified by Jerzey Rex at 5:23 PM 12/19/2006

 

Well, spark dosent occur when the valves are open so it wouldn't matter. The hot exhaust valves vaporize the fuel around them and would be easier to ignite. You have your theory in reverse.

 

 

Modified by Natural Aspirations at 8:37 AM 12/20/2006

 

The plug should be indexed with the gap towards the intake valve so the mixture is not blocked by the electrode as it sweeps in. You can buy shims to index the plugs properly.

 

Have you looked at the burn charachteristics left in the combustion chambers lately man? You have things bassackwards. The plug sparks, its not a lit lighter so I don't see your logic. You think lighting a vapor is easier or lighting something in droplet form?


Modified by theyoungone at 11:20 PM 12/19/2006

 

The gap
Some engine combinations like a bunch of spark-plug gap, and others don't run well until the gap is tightened up. On the low end of the spectrum, a gap of approximately .025-inch is commonly used, but some combinations, particularly those with high-powered modern ignition systems, can fire a gap ranging from .045-inch to .060-inch. In all situations, the gap, air-fuel mixture, and heat range must be coordinated to produce the best possible results from the powerplant. It's a case of trial and error coupled with an accurate reading of the spark plugs.

A performance trick that is seldom discussed but has been accomplished on a matter-of-fact basis for years is spark-plug indexing. Indexing spark-plugs is a relatively simple task and can tighten the gap in engines with big domes and tight combustion-chamber clearances. To index the plug, mark the spark-plug insulator body with a felt-tip pen on the side where the ground electrode attaches to the spark-plug body. Position the plug so that the gap is facing the center of the cylinder toward the exhaust valve — this is the most common arrangement; some engines respond favorably to other gap locations

Source : http://www.nhra.com/dragster/1....html

 

http://theoldone.com/archive/s...g.htm

 

Spark plug indexing has it's origins way back per the 70's (as stated in the last post by specie). I know old guys that have been doing it since they were kids and I don't think people were so stupid even back in the early days of spark ignition to not think of trying that. It's kind of a no-brainer. I think the best way to determine the optimum spark plug index position is on the dyno. I think the saying goes 'the proof is in the pudding'.

 

I totally agree with you there.

 

thanks guys...i guess this was a good topic