spark plugs 20k or 100k?

sunwolf · March 17, 2015, 09:45:04 AM

I see alot of people on here change their plugs every 20k or every year. I mentioned I was changing the plugs at 20k to the dealer and they said they only need it every 100k. Thoughts?

Brucelinc · March 17, 2015, 09:53:03 AM

When I changed mine at around 45,000 miles, the gaps had eroded to around .045 - much too wide. No way would I go 100,000 miles on plugs. If tuned, most recommend a .028-.030 gap. Checking gaps at 20,000 miles or so sounds like pretty good maintenance but I wouldn't necessarily change them that often.

ZSHO · March 17, 2015, 10:16:32 AM

This is my 3rd set of plugs since purchasing the car new,currently have 22k on her and been tuned since 3k,personally would change them every 20k,why not change them more often since they are relatively cheap to buy the MC-SP-534 and already come pre-gapped at 0.30 and especially if your tuned and the plugs being the heart of the motor.

SHOnUup · March 17, 2015, 10:51:12 AM

Put new plugs in when we got the car, changed them after 12-13k tuned miles. They looked great and all the gaps were perfect still.

Rich

SHOnUup · March 17, 2015, 10:51:43 AM

Rich

SHOdded · March 17, 2015, 10:58:08 AM

Unfortunately, there's no direct spark plug gap monitor, only inferred through misfire/lean running engine, etc. Cheap insurance to change every 20K or so, as Z said, but 30K should be good also.

wasinger3000 · March 17, 2015, 10:59:07 AM

Changed mine at 16k, some signs of the isolator getting to hot. Other than that I think 20k is to soon. Unless you are using a race rated plug.

ZSHO · March 17, 2015, 12:06:21 PM

I guess its the ocd in me as i like to take precautionary measures and not to go by dealer recommendations such as plugs at 100k,coolant at 100k,trans fliud at 150k,makes you wonder how the trans or coolant fluids will look like if followed dealers service intervals,let alone the spark plugs changed at 100k.

SHOnUup · March 17, 2015, 12:40:09 PM

Quote from: ZSHO on March 17, 2015, 12:06:21 PM
I guess its the ocd in me as i like to take precautionary measures and not to go by dealer recommendations such as plugs at 100k,coolant at 100k,trans fliud at 150k,makes you wonder how the trans or coolant fluids will look like if followed dealers service intervals,let alone the spark plugs changed at 100k.

Me too...after seeing how nice they were at 12-13k, I'll be changing every 20k. Just to calm the OCD.

Rich

Livernois Motorsports · March 17, 2015, 02:14:52 PM

We recommend changing your plugs every 12k or so once you tune your car. The reason being is that with the tighter gap and asking for more spark more frequently you will wear the more sensitive iridium plugs faster. We do make it easy for you by offering them pre-gapped already! I personally just swap them out annually...like many of you I suffer from car OCD lol.

http://www.livernoismotorsports.com/products/Precision%252dGapped-EcoBoost-3.5L-Spark-Plugs-by-Livernois-Motorsports.html

FoMoCoSHO · March 17, 2015, 02:18:12 PM

Jaimie, do you recommend .028, or .030?

Livernois Motorsports · March 17, 2015, 02:26:57 PM

Quote from: FoMoCoSHO on March 17, 2015, 02:18:12 PM
Jaimie, do you recommend .028, or .030?

We like .030
If you were to experience any blow out, you can go down to .028 but I doubt that would happen.

Note, the S550 Mustangs a little different. Most of my clients report that their cars like the tighter gap. As for the SHO and like platforms (XSport, Flex, MKS etc...) they just want a tight and uniform gap. If your gap is off on a couple plugs they are not happy about it.