What spark plugs?

[dan00001]

Mine is an 86' by the way.

[SherwoodNash]

If it was me, I'd change them for the year specific ones for your SJ.

https://www.ngksparkplugs.com/about-ngk ... lug-basics

[dan00001]

Thanks Sherwood, think I will.

[ScottieJ]

Tbh some of it will depend on how tired the engine is and if it has the original engine, what you set your timing to and how you drive your SJ.

I personally run more ignition timing than the factory specs and my sj is kept high in the rev range a lot.

I would imagine the change from 5es to 6es is related to the change in engine capacities, the older 1324cc has an 8.9:1 compression ratio while the 1298cc has a higher 9.5:1 compression ratio so it would want a cooler spark.

There shouldn't be any issues running the 6es but if it'll give you peace of mind swap them for the 5es, might be worth checking that it's running the original 1324cc block as well before swapping them.