OK I am ready to replace my spark plugs and wires now, only one thing not completely sure about.

Found there is a specific tightening torque for plugs as 12.8-17.7N.m

I do not have any torque rachet, so I really dont know how much torque is that. BTW. I did some search and some DIY mentioned use hand to tight only, some mentioned after hand tight, use rachet to tight further. So I guess my question is:

1\ should I use rachet to tight the plugs?
2\ How can i control the tightening torque? any specific way that I can tell it reaches the torque requirement, When I work with my hand or rachet?

Thanks a lot

 

Do you have a bathroom scale? Push down with your arm until it hits 12 pounds. Remember how that feels. Give it a shot. Another way is to tighten it tight.
Standard seems to be finger tight. Snug with the socket and then 1/4 turn more.
Be sure to use Anti-Seize.

 

so it's like. I use finger tight first until I make it the tightest I can with my hand, then use ratchet to tight it for 1/4 more turn?

 

You have it right.

 

not so sure if u got it right or I interpret it wrong.

As of my understanding, u gonna tight the plugs first with your bare hand and when it's tight enough, you gonna use the ratchet to tight it 1/4 more turn.


I think you should buy a torque wrench. Peace of mind. The first time you've use it, it's paid off.

 

Peace of mine.

WTF is Peace Of Mine?....you a miner?

 

fixed...kb error..lol..

 

Be careful that the spark plug is actually seated when just using your fingers. It's really not uncommon, especially on an engine with significant miles on it, for the threads to be not perfect... And putting one in as far as you can with your fingers only, the spark plug is still not seated.

 

try reading the side of the package

the proper NGK plugs tell you how much to turn the plug once it begins to seat, no torquing req'd

 

ps: it is more than 1/4 turn

 

It's usually safest to install the plugs by hand, to minimize the chance of cross threading, then tighten to the specified torque with the socket wrench.

NGK recommends NOT to use anti-seize when installing new plugs, as they already have a special finish/coating from the factory, and extra anti-seize lubricant can result in over-torqueing. That said, I usually will use a bit of anti-seize if I am re-installing used plugs.

 

OK so today I finally got those plugs and wires replaced. I wasn't able to remove the wheel by my hands, damn those nuts are soooo tight. So the best I can do is jack the car up, turned wheel to right, then jumped under the car and do all the work, then jumped out to breath now and them

It was really not a easy job as I wished.

I took a look at the old plugs. Surprisingly they look not too bad. There was only one dirtier than others. the rest seems to be OK.

I did a used car inspection couple months ago from a Mazda dealer, they told me it's really time to change the plugs and wires. (But I wasn't told the coils were bad, suppose they are still OK). I've been lazy after that and receiving worse and worse MPG. Then I got a misfire when redlining the engine once. That really freaked me out. So I changed the plugs and wires, hope this makes things better. (tho- from those old plugs don't see a big necessity to change).

I will get some coils later and replace them when I feel not being lazy someday.

Thanks all for your help

 

You don't need to jack up the car or remove a wheel. If you use the standard 3/8" ratchet (about 8" long) and the typical 13/16" sparkplug socket you can lean in from the top of the engine bay and easily reach and remove the plugs with the car on the ground. You simply remove the upper trailing plug first which then gives you easy access to the leading plug below it. Installation is the reverse then do the other rotor the same way.

 

buy yourself a 1/2" breaker bar and a set of 1/2" metric sockets to get the lug nuts off, good to have anyway.

 

get a torque wrench. if you damage the thread, you will be in big trouble.

 

when did changing spark plugs become such an ordeal?

 

I can do that past my blower....

 

You likely have a bad trailing coil on the rotor that crappy plug was....it doesn't look like it has been firing for a while. Does your car run fine...but idle like crap ?

 

Very honestly the car idles very good (a little vibration when the weather was hot, but now smooth and steady at 750-800rmp)! The problem so far is worse and worse gas millage and the misfire when super high rev. Since mazda dealer told me the plugs and wires were worn, I would suppose that's the reason.

I am gonna change the coils in this month anyway