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Spark Plug Install Instructions


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I completely missed that reference too... :confused:

 

For a moment I thought "pulled an Elvis" was the new "I Hicksta'd something." :icon_lol:

- Pro amore Dei et patriam et populum -
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thanks to this thread i completed my 2nd subaru plug swap in just under 2 hours. the rotating coils worked like a charm. my only other suby swap was on a 97 outback when i was 15 and really had no idea what i was doing...took two days lol.

 

i prefer normal motors...sooo much. i change the plugs on my evo in like 7 minutes and it involves no blood!

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I will be tackling this tomorrow wish me luck, cars at 115k miles and if memory serves me correct I don't ever remember changing them.... Hopefully this will correct my poor idling issue. The car has been sitting for 2-3 months before getting the turbo replaced so I'm guessing spark plugs or OCV, and since spark plugs are going in regardless, I'll start with those.
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  • 4 weeks later...

Regarding the use of a 'cooler' plug, is this affected by altitude?

 

I'm running at around 3400ft above sea level, would the thinner air (around 90% of O2 compaired to sea level) affect the combustion or would it be negileable with the turbo boost?

Simon

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You don't need to use a cooler plug for higher altitude. Your car's ECU reads how much air is going into the engine and supplies the right amount of fuel to maintain the correct air to fuel ratio. So, since the air is thinner, it will supply less fuel, but you don't need a colder plug.
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Regarding the use of a 'cooler' plug, is this affected by altitude?

 

I'm running at around 3400ft above sea level, would the thinner air (around 90% of O2 compaired to sea level) affect the combustion or would it be negileable with the turbo boost?

Simon

 

You hit the nail right on the head- with higher elevations, the turbo still compresses air, albiet a less dense initial charge. Combustion is affected and you will lose power, but IIRC it's something like 60% less power loss with a forced induction system vs. N/A

 

In regards to answering your question, I don't think you'll need a cooler plug at elevations. Typically people making more power (stage 2 at the minimum) run colder plugs

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Not sure if anyone has said this but i would like to add that without this ratchet http://www.sears.com/craftsman-3-8-in-drive-quick-release-teardrop-ratchet/p-00944808000P?prdNo=3&blockNo=3&blockType=G3

or a breaker bar, i would not have been able to do this sense it is so tight in there. My traditional round ratchet was not even happening with either side of the more difficult plugs.

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Thanks to the OP and everyone else who contributed to this walkthrough. Replaced mine yesterday. The drivers side rear plug took longer than the other three combined. I just couldn't get the boot to center over the plug while inserting the coil/boot in to the plug well.

 

I used [ame=http://www.amazon.com/GearWrench-81213-8-Inch-Cushion-Ratchet/dp/B0014ZXXKO]this ratchet[/ame] to get it done. Thin head profile and flex head made removing and installing the plugs fairly easy.

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  • 3 weeks later...
  • 4 weeks later...

FYI: I just did the whole thing from under the car without taking off anything other than the bottom plastic shield, the 4 bolts for the wires, and the 4 spark plugs. I used 2 knuckles and a shot extension. It took about 2 hours after subtracting breaks and trips to the store (for the knuckles).

 

It would have been easier with multiple different length extensions and a flatter ratchet head (I had to back out bolts/sparks not so far that they prevented removing the ratchet, and the finish by hand... er by two index fingers and friction I mean). Not fun, but not all that horrible either, and you don't need to bother taking apart the engine bay. I had the front up on jacks, but if you have the ground clearance of an Outback (like my XT) then you should be able to do it on the wheels.

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  • 1 month later...

After reading how this is done and watching a video on Youtube, I think I'm going to go at this job from under the car instead. I was over at Harbor Freight the other day and was standing there trying to talk myself into buying this unusual looking ratchet:

 

http://www.harborfreight.com/media/catalog/product/cache/1/image/9df78eab33525d08d6e5fb8d27136e95/i/m/image_12707.jpg

 

http://www.harborfreight.com/3-8-eighth-inch-heavy-duty-flexible-ratchet-96369.html

 

Of course I couldn't come up with a reason to buy it then but now I have one!:) Between the spark plug job on this Subaru and the thermostat job on my Nissan Maxima, this ratchet should prove to be invaluable.

 

One question I have though. I see some people changing out the plugs on their GT's before the 60k mile recommendation. Is this due to a loss of power/gas mileage? The reason I ask is I'll be taking our's on a 2k mile trip the end of March and I want the best gas mileage and of course power that I can get.

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After reading how this is done and watching a video on Youtube, I think I'm going to go at this job from under the car instead.

This is what I thought looked better but was convinced by others to go from the top. I was also doing the PS rocker cover so that side was easy. I was told by a friend who works at the local dealership that their techs do the plugs from below. Of course it helps to have a lift.

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  • 2 weeks later...
  • 4 weeks later...
You do not have to use anti-sieze. The Subaru vacation pix only suggest using motor oil on the threads and in doing so make sure to only apply 1/3 of the specified torque when screwing them in.

It actually says "the torque should be reduced by approx 1/3 of the specified torque". WTF does that mean ? It could be interpreted as using 2/3 of the specified torque, right ?

 

I've always used anti-sieze and full torque, with no problems so far, but good tip !

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Yes

 

My 2005 Legacy doesn't have coil packs. So, I suppose this is for different model?

 

BTW, I can't figure out what a knuckle extension is. Can someone be kind enough to post a pic on how it looks like?? :)

Edited by _karu_
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On the 4th Gen Legacys, Subaru lowered the motor even further, down between the frame rails, so you've got an angle caused by the height of the frame rail versus the height of the spark plug hole. And the valve cover and the frame rail are so close together, it makes it difficult to get a ratchet between the two. Some have made it work without a u-joint - I did, but I had to buy a thin-line ratchet. My 2nd Gen LGT is a lot easier.

 

If you're doing this on a 2.5i, then it's possible the alignment heights are different from the 2.5LGT so you may not need the u-joint. Take a look at what room you have to work with and determine your access angles. And read this thread - lots of good suggestions in it for changing the angles.

- Pro amore Dei et patriam et populum -
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