Tuesday, May 29, 2007
Spark Plug Change
My Miata was having hesitation problems at low RPMs. The NGs indicate that the stock wires are poor quality. Plus the Miata plugs fire twice per cycle which wear the plugs and wires out twice as fast.
I checked the gap in the new plugs. They were approximately 1mm.
I labled the wire connections near the back of the engine. I believe it's 4,2, 1, 3 on a 1.8 and reverse for a 1.6.
Pull the plugs and saw some wet liquid in the spark plug holes. Not sure if it's oil or gas mixture. I had a 2nd per of eyes to look at it and it wasn't bad.
I took out the plugs one at a time and install new ones. The original Bosche plugs were in pretty good shape, but I changed them anyways. I didn't have a torque wrench with low enough of a setting, so I tighten it by holding the driver at the pivot and then added an 1/8 turn.
I was told that the plugs can be made to fire hotter by spacing the gap out. Changing the torque also changes the timing, but I forget which way. Also, I read somewhere that the direction the plugs face effects the performance. Maybe the last two are related.
When installing new plugs, use electrical grease on the top metal tip(opposite end of the gap) and ceramic, and anti-seize on the threads. The NGK blue wires had good reviews on the NGs and miata.net as a replacement for the stock. Magnecore had good reviews too, but the NGK were cheaper and seem just as good as the Magnecores.
The hesitation problem pretty much went away. I'll do a timing check next and maybe a compression check, too.
I checked the gap in the new plugs. They were approximately 1mm.
I labled the wire connections near the back of the engine. I believe it's 4,2, 1, 3 on a 1.8 and reverse for a 1.6.
Pull the plugs and saw some wet liquid in the spark plug holes. Not sure if it's oil or gas mixture. I had a 2nd per of eyes to look at it and it wasn't bad.
I took out the plugs one at a time and install new ones. The original Bosche plugs were in pretty good shape, but I changed them anyways. I didn't have a torque wrench with low enough of a setting, so I tighten it by holding the driver at the pivot and then added an 1/8 turn.
I was told that the plugs can be made to fire hotter by spacing the gap out. Changing the torque also changes the timing, but I forget which way. Also, I read somewhere that the direction the plugs face effects the performance. Maybe the last two are related.
When installing new plugs, use electrical grease on the top metal tip(opposite end of the gap) and ceramic, and anti-seize on the threads. The NGK blue wires had good reviews on the NGs and miata.net as a replacement for the stock. Magnecore had good reviews too, but the NGK were cheaper and seem just as good as the Magnecores.
The hesitation problem pretty much went away. I'll do a timing check next and maybe a compression check, too.
# posted by Mack @ 11:45 AM 
