Why different spark plugs for 84-85 vs. after 85?

cochran · Post by **cochran** » Fri Mar 14, 2008 8:30 am

Noticed that there are different plugs listed in the manuals for Sprees after 1985 models. They added an "A" at the end. The plug books say the "A" stands for "Special Application". Does anyone know what the physical difference is in these plugs and why they would change plug applications in what appears to be identical motors?

I have both an 86 and an 84 or 85 (with no kick start). I can't see with my eye any difference in the plugs and the heat ranges are identical.

Any ideas?

JOHN

MySpree · Post by **MySpree** » Fri Mar 14, 2008 1:11 pm

they have diff heads.

cochran · Post by **cochran** » Fri Mar 14, 2008 4:05 pm

And.....................................Why the different head. What does it do differently than the plain HS plug?

JOHN

Kenny_McCormic · Post by **Kenny_McCormic** » Fri Mar 14, 2008 4:31 pm

The 84-85 and 86-87 have different heads, thats all I know. Sometimes its best not to ask questions and go with the flow, and this is coming from a guy who OCDs over every little wrong detail in everything.

MySpree · Post by **MySpree** » Fri Mar 14, 2008 5:46 pm

they have diff heads, the heads are there because in the older model sprees, they have a high compression head, with a low compression piston, this meant they could run a plug with a hotter spark and it wouldn't burn the dished piston, the newer have a low compression head, and a high compression piston, a less volatile plug was needed on the domed piston to prevent melting. it says that the ranges are the same, but its not, one has alot more power.