Archive for the 'Maintenance' Category

Jul 10 2008

DIY Spark Plug Indexing

Doing a tune up? Replacing spark plugs? Just wanting to check things out? While you’re at it consider indexing your spark plugs. This is one of the few ignition modifications that can make a very small difference in engine performance. As said by the folks at Advance Auto Parts: “Real-world power gains vary. Some engines or combinations respond differently than others. In fact, all engines will pick up power, but some gains will be more dramatic than others.In the end, it can’t hurt to index the spark plugs. This can contribute to superior engine efficiency and improved economy.” So, no promises, but it can’t hurt!

Purpose: Indexing the plugs allows the flame to spread more uniformly through the combustion chambers in the individual cylinders. I am certainly not about to claim a plethora of scientific knowledge on the subject but I’ve seen many dyno charts supporting the theory and have thus accepted the idea that it’ll help. It’s really not too much extra effort on top of replacing the plugs, so what the heck.

Time: 20 minutes

- Socket Wrench
- Spark Plug Socket
- Extension


1. Go to the parts store and buy yourself some new spark plugs, preferably Denso U-Grooves or NGK V-Powers (basically the same). They’re the recommended stock replacement and generally used plugs; cheap and effective. Again, I do not profess to be a spark plug wizard.
2. Pop them out and take a look at how they get their name.

3. Mark with a marker the on the white part where the opening on the plug is. This will allow you to see where the opening it when the plug is in the head getting adjusted.

5. Go out to the car, yank your plug wires and then your old plugs.

6. Stick a new plug in and tighten it down and see where the opening is. On most cars you’ll want the opening facing the exhaust, but it’s different for everybody.
7. If it lines up perfectly stock, you’re lucky, if not, grab a copper indexing washer and throw it on the bottom of the plug and see how it works. There are different sizes of washers and all that to try and get the indexing right, so just mess around until you get it.

See if you can see how it’s lined up:

8. Once they are all indexed, slap everything together and be happy.

There are two methods of indexing, one is to buy lots of plugs and attempt to get lucky, the other is to use washers, take your pick. I chose to use washers rather than to try my luck. Less wasted gas driving to the store.

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Jul 10 2008

Basic DIY Gas Mileage Tune-Up

Here’s just a few of the more common fuel economy tips that I through together so that everyone would have a starting point for good fuel economy in reference to their car’s condition. These things won’t give you a huge boost or anything like that, but you need to start off with your car in good condition if you’re looking to go somewhere far in terms of fuel economy. So, at the very least, be mindful of these things and realize how they affect your fuel economy.

General Tune-Up Information – Whether or not you’re losing fuel economy to an overdue tune up is really a matter of guesswork, however, this doesn’t prevent you from doing the actual tune up. Once done, you will know that you’re getting the most you can out of such things. Besides, you really ought to get it done anyway.

Some common things to include in the tune up:

  • Spark Plugs – I use NGK V-Power or Denso U-Grooves just because they are a reliable, copper stock replacement that’s cheap. Check out this page to learn how to read your old plugs to check in engine operation.
  • Plug Wires – Use a digital multimeter to check resistance compared to what’s specified in your shop manual to see if you need to replace these.
  • Distributor Cap and Rotor – These parts take the littlest, tiniest bit of wear with every spark. If they’re looking ridiculously worn down from the time a replacement might be in order.

Check Timing – Make sure your timing is within specifications with a timing light. Without proper tuning it is inadvisable to fiddle with your timing or leave the car out of time.

Motor Oil – A lighter weight motor oil will reduce internal engine friction. The Honda Insight, an excellent example of across the board fuel economy, uses 0w20 motor oil to keep friction down. Do this with caution, however, as lighter oils will increase oil leakage or consumption in more worn engines.

Grounds – Over the years your grounds get corroded and icky. Clean them up or replace them with some more blingtastic audio wiring to make sure they’re running at their peak.

Battery Terminals – Just clean them up with a wire brush, they get corroded and disgusting, no one like that.

Pump up the tires – This is perhaps the best thing you can do on this list. Most tires list the maximum pressure as 44 PSI, but members on routinely step it up to 60 PSI. This may not give you a 20% increase in fuel economy, but you’re certain to gain a few percent out of reduced rolling resistance, and it doesn’t even cost anything!

If you’re interested in the safety of this change check out this police article that encourages over inflation for both safety and performance.

For more information on the fuel economy benefits of reduced rolling resistance and over inflation, check out this PDF.

Cleaning out the trunk – This is probably one of the smallest changes you’ll ever not see, but, for every ~100 pounds you haul around you’re costing yourself 1-2% of your fuel economy. So, if you’re carrying around a set of weights or something like that you just forgot about, get it out of there.

Take off that wing – Well, this isn’t exactly tune up material, but for as easy as it is to pop it off and plug the holes with some rubber grommets you might as well. Most wings are functionless, ugly things. Those that do have function increase downforce and therefore drag. While downforce may be a good thing at 100 MPH, how many fuel savers will be going that fast on a regular basis?

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