sparkers

[90xj06]

spark plugs....are the 1990 and earlier and 1991 and later inter changeable

[qwerty247]

I dont think they are.

upto 12/90 they where RC9YC4
and then 01/91 on they changed to RC12LYC

thats the champions anyway.

[90xj06]

ya i know but what are the differences. my friend has a set for a 1994 and i want to know if i can use them.

[qwerty247]

the gap on the earlier ones is bigger.
thats the only difference i know

[90xj06]

in the manual it says there both .035 in

[qwerty247]

not according to champion there not.

the rc12lyc (which is still used upto 2000) is 0.8mm

and the rc9yc4 is 1mm

p.s sorry for the metric, but thats what we use here...

[90xj06]

in the haynes manual it has .035 but maybe metric is more accurate. i use the metric when i gap any how.

[xjtrailrider]

I'm running a set of Autolights that came out of my 96' in my 90 with .035 gap and they run fine.

[5-90]

RC9YC4
RC12LYC

R = Resistor Core Plug
C = 14m/m thread, 3/4" reach, 5/8" wrench hex (Shell Design)
9/12 = Heat Range (I think 12 is somehwhat hotter, but I don't usually handle Champion plugs. I'll have to C/R to Autolite...)
C4 = "Copper Plus" Design, "Wide Gap" Design
LYC = Skirted Shell, Standard Core Nose, "Copper Plus" design.

I'd not think they'd interchange (going off of that,) but I'd check a couple other parts lines to make sure...

5-90

[90xj06]

so is there any more info im going to see if champion has a web site

[90xj06]

found that the 12 is heat range. ly is extended electrode gap. so will these still work fine.