94 Civic spark plugs: type and socket size

What size socket do I need for the plugs on a 94 Civic EX (D16Z6 engine)?

Also, I notice that the service manual notes two different plugs, one
the NGK ZFR5J-11 for "normal" driving, the other the NGK ZFR6J-11 for
"hot climates or continuous high-speed driving". My car is used mostly
for trips, not a lot of local driving. Does primary driving at highway
speeds warrant the 6J plug?

Is another brand recommended? I just discovered sparkplugs.com--pretty
cool. Anyone bought from them? A listing of plugs for my engine:
http://www.sparkplugs.com/results_app.asp?productTypeID=1&AAIA=1168747
None of these manufacturers means anything to me. It's unlikely that I
need "premium" plugs--not a racer--but if the Champion Premium Gold plug
is any better than the NGK OEM spec, the price is certainly right.

Since the last tune-up on this car was at 97K miles at an unknown date
(now at 118K), and since I don;t know whether the plugs were replaced
then, I'm thinking it might be a good idea to replace them soon.

 

sure! or maybe not, if your current plugs are already a nice grey color.

its either NGK, ND, or nothing.

when in doubt, why not?

 

If you're spending much of your time at or near 4,000 rpm, you'll need the
colder (6) plugs. Otherwise the insulator will overheat and blister.

Pull the plugs that are in the car now. If the insulators have some color
to them (doesn't matter what color as that's a function of your gas), then
you're fine. If they are bright white with tiny bubbles on them, move up a
range.

There are anecdotal reports of poor operation with anything other than NGK
or ND plugs, the OEM spec.

Personally, I've had unsatisfactory results with the "Splitfires". I don't
know if this was just my perception or if the car really did run worse, but
I didn't like them.

Champion and Autolite are domestic manufacturers. GM and Ford use them.

Never a bad idea, that's for sure. You may find little wear on your
existing plugs if they're platinums or if the car's spent much of its time
at city speeds.

 

5/8" I think. That's what I've been using to install NGK and Denso
plugs over the years. I'd also recommend a "locking extension". It's
almost essential for installing a plug. It locks onto the socket
with a little quick release switch. You can then pull it out and
the socket comes out easy. Without one, I was struggling to get the
socket out once the plug was tightened since the rubber boot on the
plug socket held on the the plug. You might also want to use a torque
wrench.

<http://www.sears.com/sr/javasr/product.do?pid=00943355000>

"3 pc., quick-release, 3/8 in. drive extension bar set. Great for
Spark Plug replacement. Includes 3, 6 and 10 in. quick-release bars."

The 6" length is ideal for spark plug tubes. You don't have to get
the 3-pc set, but the single 6" picture seemed to be incorrect.

"Premium" plugs might be useful if you intend on leaving them in
longer. They're especially useful in V6 engines where it's a PITA
to remove. As the standard plugs are cheap, you might be better
off just using standard plugs and changing them every 15K miles.
Your owner's manual probably says every 30K miles or two years.
The right spark plugs are so easy to find that it wouldn't be worth
it to mail order them unless you can get a steep discount on pricey
platinum or iridium plugs. The right plugs for your car are about
$1.50 to $2.50 each. It wouldn't be worth the shipping costs to
save on those.

Just to clarify - ND stands for Nippondenso. As a "rebranding" strategy
they were renamed just Denso in the late 90's. Their part numbers are
exactly the same as before.

If you're in the US, AutoZone carries Denso. The following says the
KJ16CR-L11 plug works in your car.

http://www.densoaftermarket.com/online_catalog.php?part=sprk&year=1994&make=HONDA&model=CIVIC

 

Thanks, guys. This is all very helpful. Locking extensions are an
interesting idea, will definitely consider it if my (stiff-bearing)
extension doesn't cut it. I just discovered quick-release in Craftsman
sockets/ratchets--very clever.

Thanks also for the tips on what to look for as far as plug state.
Tegger, I really don't drive at 4K, maybe just over 3K in 5th gear
sometimes--don't really go THAT fast.

I do sometimes push it up to 5K before shifting from lower gears, but
that's only briefly for the most part.

 

My car recommends also colder plugs for highway/hot climates. The insulator
on my 'normal' plugs changes colour to dark brown. That's after a month
driving. Would a colder plug make the burn marks too?

 

"Brown" is not burning, it's just deposits. Depending on your gas
formulation, some sort of color is expected. By "brown" you probably mean
an uneven deep tan with some gray/black mixed in, correct?

If you had a bright white insulator with bubbles all over it, then you'd be
running too hot.