spark plugs

[mbjj]

4 cyl 2.2 L. motor in both my Impreza and Legacy. I have NGK plugs in there
now. It seems that the NGK's lose their gap after only 12000 miles. If
that's the case then they have to go. What's the best plug to use as far as
holding the gap and performance? The books all call for NGK, Champion or
Nippondinsu. Thanks

 

[Guest]

I've just replaced spark plugs in my Outback '97. I decided to go with Bosh
Platinum 4. They do not require re-gap ever (according to their
advertisement). But if you don't mind to spend 40-50$ instead of 10-15$, you
can get Iridium Spark Plugs. They seems to be good and not to burn out so
fast as regular cupper plugs.

 

[Greg]

My 98 OBW had ND platinum in it from the factory. I changed them at 90,000.
Replaced them with same platinum ND's but traded the car in at 105,000.
Can't ask for better life then that.
What makes you think your plugs "lose their gap"?

 

[Edward Hayes]

What did the plug inside insulator look like? If it was white and not a
light brown you may be using a plug that has too hot a heat range for your
driving. My 2.5L engines spark plug gap (NGK standard )increases ~0.005 inch
in 30,000 miles. The insulator is a off white to light brown. eddie

 

[mbjj]

My 98 OBW had ND platinum in it from the factory. I changed them at
90,000. Replaced them with same platinum ND's but traded the car in at
105,000. Can't ask for better life then that.
What makes you think your plugs "lose their gap"?

I set them when I put them in at .040. I started to notice poor gas mileage
so I checked them again after 12000 miles. The gap was all the way to .053.
Speck calls for .039 to .044. Every plug was different and they all were
beyond range.

 

[mbjj]

What did the plug inside insulator look like? If it was white and not a
light brown you may be using a plug that has too hot a heat range for your
driving. My 2.5L engines spark plug gap (NGK standard )increases ~0.005
inch in 30,000 miles. The insulator is a off white to light brown. eddie

When I checked them out in my book it did strike me as being too hot. They
were more white than brown. I'm using the standard NGK plug that speck
calls for. I thought about going to a colder one but which one?

 

[Edward Hayes]

The extremely wide gap and variation suggest something is wrong if they were
gaped properly with a wire gage. Is the engine running ok and not too lean a
fuel mixture which raises plug tempter. Plugs not torque properly (loose)
will not transfer the heat to the cylinder and also cause a plug to run too
hot. Go the www.ngksparkplugs.com and they may advise. eddie

 

[Ryan]

So you're saying that spark plug gap makes a difference to fuel consumption,
My plugs hav'nt been changed since I bought my subi second hand 15000km ago,
@80000km I guess I can presume that the dealer wouldn't have changed them so
hopfully I may have found the reason for my rediculously large fuel
consumption. What plugs would you recomend for high performance on a 97
Legacy twinturbo?

 

[mbjj]

So you're saying that spark plug gap makes a difference to fuel
consumption, My plugs hav'nt been changed since I bought my subi second
hand 15000km ago, @80000km I guess I can presume that the dealer wouldn't
have changed them so hopfully I may have found the reason for my
rediculously large fuel consumption. What plugs would you recomend for
high performance on a 97 Legacy twinturbo?

Plugs are just one part of it. Change your wires and make sure you have a
clean air filter. They all go hand in hand. My situation is beginning to
look like the spec NGK plug is too hot. They are not burning a nice coffee
brown like they should. [maybe a touch lighter, it depends on if you use
cream or not] Mine are almost white so that tells me I need another plug.
Your question is the same one I asked in this session. I'm still looking,
but I know it isn't an NGK BKR6E-11 which is what the book calls for. The
other 2 listed is champion RC7YC4 [I never had a champion with staying
power, 30-40,000 at the most], and the Nippondenso K20PR-U11. Maybe a Bosch
this time. At any rate I'll check them in a month or 2 and switch up then.

 

[mbjj]

They were gapped properly. I check and double check just before I put them
in to make sure they're right. As for torque...I don't use a torque wrench
but I do make sure they are in there. Tight enough not to come back out. It
took a little effort to break them free but with a standard wratchet all by
hand. I don't even have a "check engine" light showing.
In another related story to NGK...I gave my son a '95 metro 3 cyl 5 speed.
Just before giving it to him I tuned it up. It had 98000 miles on it. I used
NGK's there also. He ran it for 15000 miles and noticed it wasn't giving
him the normal 49 MPG that we were getting. He checked his plugs [burning
properly] and found them all out of range. When he told me that, that's
when I checked mine and that's why I am beginning to question the plug.

 

[mbjj]

4 cyl 2.2 L. motor in both my Impreza and Legacy. I have NGK plugs in
there now. It seems that the NGK's lose their gap after only 12000 miles.
If that's the case then they have to go. What's the best plug to use as
far as holding the gap and performance? The books all call for NGK,
Champion or Nippondinsu. Thanks

How's this sound: NGK plugs are considered a performance plug and are
designed to burn hotter. They also have a short life 10-20000 miles. If
this is correct then they are performing as designed.

 

[Ryan]

will these plugs be setup with the right gap so that they can just go
straight in??

 

[Edward Hayes]

My standard NGKs on my 2000 Forester 2.5L engine go 30,000 miles with a gap
increase of ~0.005 inch and appear to be able to go another 30,000 miles.
I've had same performance with my Saabs and standard NGKs. I feel something
is wrong and it's NOT the NGKs. Are you using the resistance type(OEM) plug
wires? High performance non-resistor or very low resistance (magacore)
ignition wires will cause this type of problem because no-resistance wires
do not limit the current to the spark plug. eddie