1995 Saturn SL1, Which are the better spark plugs to use for the SOHC
engine?
Car: 1995 Saturn SL1 SOHC, 1.9L., VIN 8th digit = "8" - engine type SOHC
I've used AC Delco, Motomaster, NGK, and Champion standard copper spark
plugs in the past. I see that both NGK and Champion make different spark
plugs for either the SOHC or DOHC engines.
I read the Champion Spark Plug Handbook...
http://dodgeram.info/Engine-Gas/Spar...html#discussed
...."heat range is a measure of the spark plug's ability to remove heat
from the combustion chamber."...
From the Champion catalogue for each engine the recommended plug is:
SOHC RC14YC a Hotter Heat Range.
DOHC RC12YC
I've been using standard type plugs for years, from Champion the RC12YC.
Actually suppliers like Canadian Tire list the RC12YC for my car. They
do not always stock the RC14YC.
I'm wondering if not using the RC14YC has caused a failure for high NO
ppm in a recent emissions test? The present ones I installed in May
2007. Is the RC14YC type absolutely necessary or is the RC12YC fine?
From a recent post of mine.... 2008/11/25
> 1995 Saturn SL1 fail Emissions Test for high NOx
>>
>> Car: 1995 Saturn SL1 SOHC, 1.9L.
>>
>> Symptom: Drive Clean Emissions Inspection Report show failed reading for
>> NO ppm:
....
>> The info included suggests for high NOx on driving test...
>>
>> 4.-excessive spark advance... I change the spark plugs myself, gap them
>> properly at 0.040”, the current four are one year old, Champion brand
>> RC12YC, traditional flat copper core. I do not use platinum or iridium
>> plugs.
....
> Emissions Tests results...
>> --------------------------------------------------------------------------------------------------------
>> Results: Nov 2008
>>
>> HC ppm @ 40Km/h ASM 2525, 23, limit 75, pass; @ Idle, 53, limit 200, pass
>>
>> CO % @ 40Km/h ASM 2525, 0.01, limit 0.42, pass; @ Idle, 0.00, limit 1,
>> pass
>>
>> NO ppm @ 40Km/h ASM 2525, 1149, limit 576, FAIL; @ Idle, -, limit -, -
>> (not done)
>>
>> @ 40Km/h RPM 1780, Dilution 14.41, valid
>> @ Idle, RPM 745, Dilution 12.80, valid
>>
>> Analyzer Software Version: 4.54
>> --------------------------------------------------------------------------------------------------------
>>
....
Thanks, Roger