DIY - Spark Plug Indexing - Page 4 - Fuel Economy, Hypermiling, EcoModding News and Forum

hansj3 · 05-11-2009, 04:36 PM

not to dredge up an old thread, but wankel plugs are different....way diffrent...

OfficeLinebacker · 05-12-2009, 08:02 PM

no worries, I love that you used an old thread instead of creating a new one.

Those are some interesting looking spark plugs. Do all Wenkel plugs look like that, or is that just one brand? Closest thing I've seen are Bosch Platinum +4s.

hansj3 · 05-12-2009, 09:11 PM

the 12a had a goofy 3 prong design that was almost flush with the thread ring

Funny · 05-12-2009, 09:19 PM

I remember those, Had to drive to three different Autozones to get the plugs for my 85 Rx-7. Gotta love those rotary engines. The reason that they are shaped that way is to allow the apex seal to pass over the end of the spark plug without hitting an electrode (in this case the four quarter circles surrounding the center) but still allow ample room to spark the mixture. There are also two different spark events per ignition sequence, called leading and trailing. They help keep the rotor moving in the right direction.

Click image for larger version

Name: RotaryEngineAnimation.gif
Views: 45
Size: 26.1 KB
ID: 3464

Click image for larger version

Name: RotaryBlockAnimation.gif
Views: 32
Size: 61.5 KB
ID: 3465

hansj3 · 05-12-2009, 09:40 PM

i wonder what else they would fit...

OfficeLinebacker · 05-12-2009, 10:36 PM

Quote:

Originally Posted by hansj3

i wonder what else they would fit...

It might fit other applications but chances are it would not work as well (ie be as efficient) as a plug that protruded into the CC

nateluke · 05-13-2009, 12:55 AM

To go back to the original topic, if you're having trouble positioning the plug opening, make a mark with a sharpie on the ceramic. Instant results! Hope it helps someone.

hansj3 · 05-13-2009, 11:01 AM

i ended up doing mine the hard way.... when i did my head gasket i put them in before i put the head on and just jockeyed them around until i got what i wanted but i had them facing the center with maybe a bias towards the exhaust valve... big one

Southcross · 05-21-2009, 11:53 AM

I've looked at doing this over the last couple of years... one question I cant seem to find a definite answer to: On a flat faced sparkplug (the kind that has the integral washer), I saw somewhere to "remove" that washer before installing a copper "shim" one. Elsewhere I don't see a mention of removal of the integral washer...

Funny · 05-21-2009, 12:38 PM

You're not supposed to remove that washer, it provides the positive seal for the plug. The copper washers are for indexing only.