Rotary engine spark plugs

[kevinorhoades]

I just changed the plugs on my 87 that I just got, and I realized the person that put in the plugs last did them all wrong. The two trailing plugs were in front, and the two leading plugs were in back. Following the instructions of my Haynes manual, I put the two new leading plugs in the bottom holes, and the trailing plugs in the top holes. Does it really matter though? The car seemed to run fine when I drove it homes with the plugs all wrong. I bet this is quite common.

[Steel]

Well... it should run a little better now. If it didn't matter, then they would have bothered with the whole lead plug/trail plug stuff.

[BDC196]

Originally Posted by kevinorhoades

I just changed the plugs on my 87 that I just got, and I realized the person that put in the plugs last did them all wrong. The two trailing plugs were in front, and the two leading plugs were in back. Following the instructions of my Haynes manual, I put the two new leading plugs in the bottom holes, and the trailing plugs in the top holes. Does it really matter though? The car seemed to run fine when I drove it homes with the plugs all wrong. I bet this is quite common.

It sort of does matter and yes it's quite common. The most important thing here to remember and keep an eye on is to _make sure_ that the spark plug wires themselves are connected properly. The leading coil/ignitor located near the driver's side headlight is a single coil with two outputs -> each of those plug wires goes to the two bottom (Leading) plugs. Conversely, the trailing coils/ignitor pack near the driver's side shock tower/firewall has a T1 and T2 pair of coils -> T1 goes to the front rotor's trailing plug while T2 goes to the rear.

The stock plugs (BUR7EQ and BUR9EQ) represent different heat ranges. NGK uses numbers as their heat range classification. The number '7' indicates a hotter plug. In this case, 7's are used in the leadings for a hotter plug where 9's are used in the trailings. The idea behind it is to keep a slightly colder plug in the trailing position to offset the chance of the plug becoming too hot and inducing something called 'pre-ignition'. This is why they've got them positioned the way they do.

B

[flex339]

wow I learned something new today. Thanks for the spark plug info.