Mazderati

Is there anything good or bad associated with using the newer "solid top" style of rotary spark plugs vs. the older "four-pronged" style of rotary spark plugs?



I have a new set of the "solid top" style plugs (stock plugs for the FD) laying around and am debating on installing them into an older 13B in a stock GSL-SE.



Opinions?

j9fd3s

i never noticed a difference they seem to work the same

Jeff20B

The newer style like direct fire better than through the cap-n-rotor. I've seen the newer style work relatively well through a cap and rotor, but I wouldn't count on it being 100% reliable. I've seen an FB coil with a burned-through insulator on a REPU with FB ignition and FC plugs. Yep, through the cap and rotor with later style plugs may have caused this.



One way to look at it is to match the plugs with the ignition system. If it's throught the cap, use BR8EQ-14. If it's direct fire, use BUR7EQ. The number indicates the heat range, which can vary.

j9fd3s

thats why i went back to the stock plugs i figure i should be using the ones for the ignition i'm using

eddierotary

i have BUR9EQ and im using a FB dizzy and it work grea, the only difference so far i seen that is harder to get the engine flooded with them. other than that is the same

Jeff20B

I'm a direct fire advocate. So with that in mind, I'd use BUR7EQ on leading, and BR8EQ-14 on trailing. This is of course on an FB distributor with DLIDFIS and stock trailing.



If BUR7EQ tends to be a little too hot, and BUR9EQ are too cold, I'll order a set of BUR8EQ.