joefnh
Well-Known Member
- Joined
- April 30, 2005
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- 223
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- City, State
- New Hampshire
- Year, Model & Trim Level
- 03 XLT
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- KA1DGB
Indexing Plugs -- Good Results -- MPG gains
This past weekend I was going to try out some racing plugs from Autolite (model AR93) I have been trying a few different plug types out recently and this time around decided to try indexing the plugs as Al described in a previous thread.
I was able to find the indexing washers at a local speed shop for ~ $14.00 but could not find the nifty tool to help with positioning. I think that I came up with a fairly inexpensive yet effective replacement.
I first tried these plugs out without indexing them, then after about 30 minutes of testing I allowed the engine to cool down so I could try to index the plugs towards the center of the cylinder.
The 2 things that I noted with indexing the plugs was both a smoother idle and acceleration
The following is the method that I used:
First I gapped all the plugs to .065", inspected the plugs and prepared my 3/8" extension with a tightly applied tie wrap to be used as a marker as to where the electrode face of the spark plug is. See the 1st & 2nd pictures
Next I decided to try the new plugs without indexing them this was done to basically establish the performance of the new plugs un-indexed.
Aligning the tie wrap to match up with the electrode 'face' I installed all six plugs and noted that all but cylinder 3 had the electrode face in the worst possible position facing away from both valves.
I was surprised to see the repeatability of the position across all 6 cylinders and plugs when installed... Unfortunately in the wrong position. See the 3rd picture
After a 30 minute test run and cool down period, I reinstalled the plugs using the prescribed washer to bring the the electrode face centered between the intake and exhaust valves. As stated above good results were noted See the 4th picture
Overall this process only takes about 30 minutes longer than a straight plug change. I am currently monitoring MPG for any gains, but even if no gains are realized this was worth it to improve just the idle.
This past weekend I was going to try out some racing plugs from Autolite (model AR93) I have been trying a few different plug types out recently and this time around decided to try indexing the plugs as Al described in a previous thread.
I was able to find the indexing washers at a local speed shop for ~ $14.00 but could not find the nifty tool to help with positioning. I think that I came up with a fairly inexpensive yet effective replacement.
I first tried these plugs out without indexing them, then after about 30 minutes of testing I allowed the engine to cool down so I could try to index the plugs towards the center of the cylinder.
The 2 things that I noted with indexing the plugs was both a smoother idle and acceleration
The following is the method that I used:
First I gapped all the plugs to .065", inspected the plugs and prepared my 3/8" extension with a tightly applied tie wrap to be used as a marker as to where the electrode face of the spark plug is. See the 1st & 2nd pictures
Next I decided to try the new plugs without indexing them this was done to basically establish the performance of the new plugs un-indexed.
Aligning the tie wrap to match up with the electrode 'face' I installed all six plugs and noted that all but cylinder 3 had the electrode face in the worst possible position facing away from both valves.
I was surprised to see the repeatability of the position across all 6 cylinders and plugs when installed... Unfortunately in the wrong position. See the 3rd picture
After a 30 minute test run and cool down period, I reinstalled the plugs using the prescribed washer to bring the the electrode face centered between the intake and exhaust valves. As stated above good results were noted See the 4th picture
Overall this process only takes about 30 minutes longer than a straight plug change. I am currently monitoring MPG for any gains, but even if no gains are realized this was worth it to improve just the idle.
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