Spark Plugs

[Dark Authority]

Okay.. i just did something really stupid

I went down to repco and bought the wrong plugs... well the guy gave me the wrong plugs and i didnt check.. and i already put them in my car and started the car up.

Car is fine i guess

I bought NGK ITR5F13... but the ones off the car are ILTR5A13G.

Side by side.. the new one has a slightly shorter screw thingy..

What should i do now?

Would any damage be caused if i kept using these new plugs. They are designed for the mazda 3 engine anyways.. so yeh

[2XS]

Check the NGK website, or maybe elsewhere.

The difference is the L, the A and the G.

Find out what they mean, and you'll be fine. I know P used to be for protruded, R was for resistor etc.

[Dark Authority]

Okay.. i've checked. They're both EXACTLY the same sparkplugs.. SOO bloody expensive as well.

The only difference is the thread length..

. Big difference in performance is the spark plug is shorter?.. Bad for the engine?

Going to repco tomorrow to try my luck to get it exchanged.. but i dont like my chances.

[2XS]

Sometimes having the thread not exposed into the combustion chamber can be a good thing.

How much shorter is it? about 15mm. I was sold a set of std 3 plugs before I knew that MPS have different plugs. I had 2 cracked plugs at the time. It took me 2 weeks to get the right ones.

It's their fault, they should give you the correct ones.

[Dark Authority]

probably only around 5mm shorter.

Its their fault for giving me the wrong ones.. but its also my fault for not checking.. so they could say that..*shrugs

[lazydog]

I run the Denso ITV24's.

Perfect fit... fells great!

But stock setups should run ITV22.

I'd be interested to hear how the NGK ones go.
Anyone running them @ the moment? Stock replacement, or one step colder?

[Doug_MPS6]

You really have to be aware of plug thread length. It's far more critical than plug temperature in the first instance. I had a mechanic install long-nose plugs in one car I owned that required short-nose plugs. Result: on first start, the valves in the hemi-chambers planed the ends off all the plugs. Fortunately no other damage was done, no bent valve stems. But I had to retrieve the bits from the cylinders, which I was able to do without removing the heads.

As to running the car with short plug threads well shy of the cylinder or the end of their thread, there is a risk that you will certainly carbon up and may ultimately erode the thread on the bore of the plug aperture, either way rendering them near to fully-useless for any future use of the correct length of plug.

Get shot of them and put in the correct ones. If possible, dump them back in the hands of the fool who supplied you with what you didn't ask for, and exchange them for the correct ones. Got the receipt?

[Dark Authority]

Okay.. went into repco and they gave me a nice refund even though they were used. Told them they were not the same and they couldnt find the one suitable for my car...*weird.

Anyhow.. got a nice $120 refund since the plugs cost $30 EACH!..><"..

[lazydog]

$30.. ouch!

[mpsgarage]

running the wrong spark plugs will cause a lot more damage to what you can think.
Wrong length changes where the spark is in the combustion chamber
Wrong gap will change your spark or might not even spark at all.
Changing you plug from resistive to inductive can effect your coil packs
temperature range
fuel used
The list goes on, a simple mistake of using the wrong cheap part will cost you a new $$$ engine.
Make sure your spare parts suppler knows what we need. Not whats on his shelf.