I took my car in for a failed dyno tune in April (don't ask, it's irrelevant), and while I was there, the tuner installed new spark plugs (NGK BCPR6EIX) and charged me $50 for it. At that time, I didn't realize they installed incorrect plugs and I didn't think anything of it since they're an experienced Honda tuner.

Fast forward a few days and I notice the car starts up funny when cold. At first, I thought I needed to reset the ECU, and that it wasn't a big deal. Well lately I decided to go all out and run a compression test and check the gaps on the plugs. Sure enough, the plugs were wrong and the gaps were too narrow and after adjusting them to spec, the car starts up much smoother in cold. Compression test results came out to 240PSI across the board so no engine damage, but I was wondering what the risk is in running these plugs? They run 2 steps hotter so I realize there is a small chance of damaging the engine, but is this something that requires immediate attention?

 

If the gap is out of spec the spark will be off, if the ECU can correct, no problems. If the ECU cannot, YIKES.

Heat could be a problem. Some cheaper plugs melt and drop parts into the motor.

 

they are one step hotter than the factory plugs. I haven't looked at them specifically but they will have a different length than the stock plugs, either slightly longer or slightly shorter. Comparing the specs on sparkplugs.com will tell you the difference. One plug is ISO length and one is JIS length http://sparkplugs.com/glossary.asp?kw=JIS&manID=0&pt=1

The difference in height appears on to be mostly on the top half of the plug, the coils should be able to adjust to the slight height difference. A lot of performance shops will swap a number of NGK plugs that have similar appearance, such as BCPR, BKR, ZFR sizes, but they can all have slight differences.

I would pull them out as soon as you can, and reinstall proper sized and proper gapped plugs. The risk isn't overly high, but I wouldn't chance it with a hotter heat range.

 

I was under the impression that if they are an iridium or platinum plug that they are gapped from the factory, since they have a coating that could come off. Being how they are the wrong plug and you had to gap them would lead me to think you should take them out and put the correct plugs in that are gapped correctly and are for that application.

 

The fact that they are hotter than stock is enough reason to swap them ASAP.

 

BTW, Depending on your driving habits up there in Chicago, you may get benefit from a plug that is colder than stock, but not hotter than stock.

 

i never even heard of anyone using a hotter then stock plug? thats just crazy.
get the ngk 2668...love em. you just have to gap them.

 

My car is 75% used for autocross/track, so theoretically, colder plugs may be beneficial, but I ended up ordering new OEM plugs instead. They should be here tomorrow so I'll be installing them asap. Thanks for the advice.

Edit: They won't be here until Monday . Looks like one more autocross on Sunday with these plugs...

 

50 bucks for a plug swap, I want in that business. I don't even let my tuner change my plugs while tuning, and I bring sets of my own.

 

$50 bucks included the cost of the plugs. But I had to spend another $58 for new plugs so now I've spent $108 to get back to square one.