Do you guys ever reuse spark plugs? I replace them at every 3000 miles with NGK #5255, and the used plugs are almost as clean as new. No carbon, no anything.. I also have an ultrasonic cleaner which can restore it to near-new condition. I've been buying new plugs every time, and now I have 24 shiny mint condition plugs. Doesn't look like I can change gap on these plugs either. Only thing that changes is the crush washer, but they all torque to 9ft/lbs smoothly without issues. any thoughts?

 

They can get cracks in the ceramic, and leak compression as well.

 

Thats excessive unless your racing the engine everyday. How you drive, your dwell settings, and the amount of oil in the combustion chamber is what really effects your plugs life.

 

i think you could reuse, they are good to 30,000miles in a stock engine, and even a modded street car should do 15k

 

i think my dwell is on the high side around 4.25-4.5ms, but the plugs look just fine. i should check my coils after running for a few minutes though. probably reuse these before I chuck them out. thanks all.

 

Speaking of plugs, I just installed a set of NGK 2669. The factory style plugs foul out way too easily. Their design allows for the smallest of debris to quicky foul them out. Plus I'm tired of the occasional sputtering/misfiring they're know for. Will see how they work out once I get a new alternator.

 

someone once told me the purpose of our flat bottom plugs were to aid with containing ignited gas in the compression chamber at the leading hole and fuel injected air from escaping into the exhaust chamber at the trailing spark hole. makes sense to me?

 

Plugs look good? No electrode rounding? No cracks (however fine)? No chips? Threads are good? No fouling? etc.?

Reuse them.

 

That may have been the design theory years ago but who knows? The 8 plugs are similar but have a larger cavity around the electrode and grounds towards the top so they don't misfire much at all. They are perfect and last a really long time. I personally just can't see myself paying $25.00 x 6 a plug every 12k or so.

 

are you talking about NGK BUR9EQP's? those are outrageous prices. I get mine from o'reiley or amazon for about $8.50 each. o'reiley gives you 1 year warranty. I used to shamelessly swap them out using their warranty but as I got older, my conscience wouldn't let me do that anymore heh..

 

No! The 8 plugs are Ngk 6700 and 6701.

http://www.ngk.com/product.aspx?zpid=10143

 

I dunno about the 6700/01 plugs, but the BUR9EQP's come with a 1 year warranty, no questions asked kinda deal. you can manage to get an extra set free if you daily drive...

 

You can also use Denso Iridium race plugs part#5719 (IREO1-27) however they cost about $35 each, but they will outlast stock NGK plugs anyday.
That part # is equivalent heat range to BUR9EQP

 

I ran a set of those piston type NGK's 10.5's on the previous 550rwhp 13b. I didn't change them for around 5k miles and found the ceramic that surrounds the electrode to be cracked and/or completely missing on a few!!!!

Now, I'm not sure if this is dangerous or not, but I feel as if the internals of the engine may not like to eat ceramic! What do you guys think?

 

Yes, it is dangerous to your engine. Cracked and/or missing ceramic can lead to poor or no spark. Cracked and/or missing ceramic is also typical of a spark plug is not of the proper heat range which will also result in poor performance and necessitate changing them often.