[SyTyArchives]

I finished up this how-to guide today. I'm coming up on another plug change, so I figured I'd throw this together while I was researching spark plug part numbers.

Replacing Spark Plugs on a 2ZZGE Engine (Elise, Exige, Celica, Matrix, Vibe, Corolla) | HowTune.com

In my research I found some interesting info regarding the use of anti-seize. I see random people recommending the use of anti-seize on spark plugs on forums, so I wanted to see how important it was (I didn't use it last time I changed the plugs on my Elise).

As it turns out NGK says not to use it as modern plugs that use a plating on the threads specifically for aluminum heads (spark plugs with shiny threads).

Apparently if you use anti-seize on this coating, the torque readings are unreliable.

 

[<@¿@>]

You left out the proper torque for the ignition coil screws. The 6-mm screws with the 10-mm head (wrench). Those are NOT 10-mm screws BTW, they are 6-mm screws that require a 10-mm wrench. The proper torque for those screws is;
Torque: 9.0 N-m (92 kgf-cm, 80 in.-lbf)

 

[Gunpilot]

Dissimilar metals? I would use it. Most plugs are nickel coated on the threads but nickel isn't aluminum. Also with the way Loti are prone to water getting in there, your asking for it!

 

[jefrac]

Very well done write up! It is not what I needed, but the one you did on clutch replacement.... bookmarked that one for future reference.

Thanks :up:

 

[turbophil]

Better to use the torque suggestion on the spark plug box than a blanket statement of 13ftlb. It's a crushable washer that is used our NGK plugs. The crushable washer is what dictates the plug torque. The box states to turn 1/2-2/3 past the initial seating. At 3/4 turn, the washer will bottom out, FWIW. That's OK, but you had better have a good feel for whats too tight/loose at that point. I saw a pics of the outcome from a shop over tightening the plugs so much that the porcelain cracked and turned the plugs into bullets. Literally shot the porcelain through the coils, the cover, and boot lid. The plug's metal housing still tightly secured in the head... So yes; 2/3 turn past initial seating is good policy...

Additionally, this statement " Do not apply to electrical contact points as its actually an electrical inhibitor" is not correct. The dielectric is displaced by the metal to metal contact of the coil spring in the boot and the sparkplug allowing for an excellent connection. The dielectric around the contact point will actually help to protect the integrity of the connection, help prevent coil arcing, etc...

-Phil

 

[Gunpilot]

Phil, what is the normal life you will get out of a set of NGK coppers? A track day, 3-4 auto crosses, 3 months DD?

 

[turbophil]

They wear over time... a lot more time than the average Lotus will see in a year. I replace them in the winter when I freshen the motor, but they don't need it...

 

[Gunpilot]

Thanks Phil.............

 

[turbophil]

There was one season I replaced them every time the oil pump failed. That got old... then I went to an external oil pump and ultimately a drysump... Now I just replace them in the winter.lol

 

[Nessal]

Great write up!

 

[SyTyArchives]

I'll make a few tweaks to the article from your feedback, thanks guys.

Phil your point about the metal to metal contacts displacing the grease sounds right. I'm just not positive having it globbed in there is a good thing... I'll do some more research on it though.

 

[SyTyArchives]

Phil, I found this thread from a while ago that indicates it may actually be a good idea to use grease on the entire coil shaft to help prevent incorrect arcing from occurring there: http://www.lotustalk.com/forums/f25/coil-pack-arcing-77822/

 

[SyTyArchives]

Very well done write up! It is not what I needed, but the one you did on clutch replacement.... bookmarked that one for future reference.

Thanks :up:

Yea, that was quite an undertaking your first time in.

 

[SyTyArchives]

Better to use the torque suggestion on the spark plug box than a blanket statement of 13ftlb. It's a crushable washer that is used our NGK plugs. The crushable washer is what dictates the plug torque. The box states to turn 1/2-2/3 past the initial seating. At 3/4 turn, the washer will bottom out, FWIW....
-Phil

I updated the article to follow NGK's instructions.

Spark Plug Installation - Technical Information - NGK Spark Plugs Australia

Interestingly NGK lists torque rating between 18 and 21.6 lb-ft. for 14mm thread diameter plugs going into aluminum. This differs quite a bit from the Celica manual's stated 13 ft-lbs. I can only assume this is a result of changes to this spark plug's design.

They also have this terrible page describing the method you mentioned: PLUG STUDIO / NGK

 

[Gunpilot]

I found when it comes to dielectric grease its like anal lube. You cant use enough!

How did I find this out? I thought my coil packs were dirty, sticky so I cleaned them. No new grease on the install and the outcome was interesting.

 

[Nessal]

Are you guys using the grease on the entire coil shaft or just where the spark plugs goes in?

 

[<@¿@>]

Very good information for our Lotuses! Thanks for your hard work.

Being an engineer, saying to use a 10-mm socket to torque the bolts would be much more accurate than saying to torque the 10-mm bolt because they are 6-mm bolts.

Also, technology does change, so using NGK's current information would be much better than using a 2005 manual that was written in the last millennium. Just because you probably can no longer buy the plugs that where made 10 years ago...

 

[Prolene]

I like the OP's write up. Love the font size for my old eyes.

 

[Vulcan Grey]

Are you guys using the grease on the entire coil shaft or just where the spark plugs goes in?

Yes, for those that have had arcing problems. The plastic of the coil on plugs for the Toyota 2ZZ apparently aren't a good enough dielectric... So people have solved their misfire problem by slathering the whole plastic part of the coil on plug lead that goes down into the spark plug well in the head.

 

[Vulcan Grey]

Also, technology does change, so using NGK's current information would be much better than using a 2005 manual that was written in the last millennium. Just because you probably can no longer buy the plugs that where made 10 years ago...

I can and do still buy the NGK R plugs that Lotus specified 24 years ago... The copper plugs may not last as long, but they work better on a turbo than all the platinum and iridium plugs that are available today. And since each are only a few $, I can afford to replace them every 10K, and get a good indication of the health of my engine as well.

Speaking of dielectric grease, it also helps reduce stress on the connections inside the coil plug wires or the coil on plug connections, by making the plug wires easier to remove without damage. I had some plug wires fall apart on the Esprit with heat and being pulled off over the years, because they didn't have dielectric grease.

Another source of current leakage is moisture in the air, and oils on the surface of the rubber connectors and wires, the moisture and oils can conduct current along that surface and cause there to be less current for the circuit. This is especially true for the older high voltage plug wires.

The video is incorrect IMO saying that the dielectric grease should not be applied to the connectors... As Phil said above the contact resistance of a metal on metal contact is good enough to scrap through the grease, and the grease will actually help prevent oxidation of the contacts over time. If you leave a pair of electrical contact exposed to the air, then they will over time degrade until they aren't contacting. This even happens with titanium, which is normally very corrosion resistant. The surface oxide will prevent electricity, and you have to scrape the contacts to get it to work again. Gold is usually the solution to this, but it depends on the quality of the coating.