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Hey guys,i changed my own spark plugs today for the 1st time,and apart from the fact the car is still Running:).....im not so happy.

I previously had some ngk's gapped to .55mm and my car was running fine at 10psi..,this was done by a workshop, and they fixed my missing issue.

But i decided to change as i thought .55mm was quite low for a car with jst pod/zorst and fmic running 10psi.

So i went and brought some ngk's that alot of ppl on this forum use (dont know the gap rating, but the outlet store said they are close to 0.8mm)

I installed using a guide posted on this forum (which greatly helped), and after all had been done, i took the car for a spin, and anything over 5500rpm would make the car pop like mad!

so im thinking the plugs arent gapped properly?

few things id like to ask

1) how good are the spark plug gap gauges(wire ones)

2) when removing sparkies should i spray compressed air around the area and be done with it?

3) Do these spark plugs have to be torqued down?, ive been using a rathchet to tighten firmly.....is this advised?

thanks in advise, i may have to do this all over again in the wekend, for now ill go back to stock boost:)

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Hey i think they just gapped them to .55mm to be sure that it wont ping/pop anymore, as it was 1.1mm beforehand.....so i have nevertried .8mm.....and it seems that the ones in my car at present may not quite be 0.8mm(i never had any tools to measue:(

one other question though.....whats the best way to clean the area arounf the spark plugs???using something like Dust off (can of compressed air thats used most often for cleaning electrical components keyboards etc....)

i'll be having another go soon.

I was reading some other threads,and it seems that i should have cleaned the area before even removing the plugs(incase of anything going into the chamber).......i didnt do this....could this be a cause of the problem?i hope i havent done something to my engine.

leave the plugs in when cleaning the area!

as mad082 said, if they were gapped to 0.55, think there will be a coil pack problem or something if its missing with 1.1 or 0.08!

been there and had the same issue

Just in case you doubt the first two recommendations...

If your car is missing with 0.8mm gap then it is time to replace you coil packs. If you do decide to replace them, you will be much better off buying Splitfire coil packs.

So double check your gapping, just take the plugs to your local mechanic, and make an educated decision.

whoa, hold up the love boat, if you just popped your spark plug changing cherry, i would go back and remove the plugs, there is a very real chance you may have cracked a plug. they can be quite delicate. also double check the gaps.

i have experienced this with even a well known "performance" shop (bob romano's) having cracked a plug in my 25 for me to discover. it's not hard to do even if you are experienced!!!

  Quote
i have experienced this with even a well known "performance" shop (bob romano's) having cracked a plug in my 25 for me to discover. it's not hard to do even if you are experienced!!!

i never heard of that. i dropped 2 of mine before i put them in. 10,000k's at boost between 12 and 14psi and no problems yet. i know they can be broken, but i wouldn't say they are delicate.

Edited by mad082

how can you tell if youve cracked a plug, and how would it happen?overtightening?

also it seems everyone thinks my car is missing at 0.8mm gap, i dnt actually know the gapping on my pressent plugs, and the last ones i had went from 1.1mm down to .55mm, we never tried .8 back then.

So i think my coils maybe ok

if it is missing at 0.8mm gap then there is a spark issue, and you aren't running enough boost to have issues with a 0.8mm gap unless the coil packs are lazy. 0.55mm gap is extremely small! much too small for low boost.

Spitfires are a direct replacement..

What car/engine? I'm assuming RB25 as your listing 10 psi as a mod.

Do you have any aftermarket engine management?

Mine had the same issues with .8mm plug and the same mods.

Coilpacks were repaired, made a difference, but still mild pop. Really bad on cold nights.

Got the car tuned with some aftermarket managment, works a treat! More power too. Never popped again. On researching it I found that the issue was just the mixture was getting to rich to ignite.

Alot of people on here have replaced the coil packs and the problem goes, however, alot of people have also replaced coils and the issue had not go away as it was something else, like rich mixture...

they should not be too tight. especially with an alloy head it's very easy to stuff the head by overtightening. there are torque specs in the shop manaul and it's very low.

you should have checked all the gaps before installing them. also, no one has asked yet. what heat range are they?

always clean around the plugs BEFORE you remove them as the whole point of this is to stop sh1t dropping down into your engine.

  nsta said:
cheers, ill confirm they are gapped right and let you guys know.

Btw no one ever told me how tight the sparkies should be tightened?

According to the NGK website, they should be torqued to around 20 lb/ft (which isn't actually all that much). And they should be installed into a COLD engine (well, torqued down when the engine is cold).

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