I have a 92 gta with L98 motor. Stock heads.. proper plug is acR45ts which is a tapered seat plug.. The plugs that are in it
are ac r5ls which are not tapered seat and (measuring from where the plug would seat into the head) the electrode extends
about 3/8ths of and inch futher into the head therefor being deeper into the combustion chamber... Any thoughts and to how will affect the flame front and power... apparently no danger of hitting the piston as they have been there for about 10,000 miles now.
I know this is not a prom burning question
and I also posted it in the tech/engine board but you guys who frequent this board seem to know much about anything so I felt you guys could give some good input... thanksjavascript:smilie(':hail:')
javascript:smilie(':hail:')

 

Put the correct plugs in it.

 

The Al L98 heads are machined to accept tapered or square seated plugs.
Use the correct reach. That is incredibly important. Shrouding the plug by using one too short, or changing to a non extended plug to an extended one is like changing the timing 3-4d.

 

Shrouding the plug by using one too short, or changing to a non extended plug to an extended one is like changing the timing 3-4d.


Amen to that, ask me how i found out :-)

If its not one thing its one of the 100 million others. I second going with the proper plug
LAter
Jeremy

 

OK, how did you find that out?.

 

For all intents and purposes the plugs always looked like garbage, car ran great did everything it was supposed to but the plugs always looked like they were drenched with fuel(dark and wet)...

that and happen to pick up a GMPP catalog and go hey they're using different plugs lol whoops................it easy to miss something dumb so keep your eyes open

lol
LAter
Jeremy
PS i swear that was a long time ago honest :-)

 

ok question.. the plugs that I just put in which are the correct plugs according to gm, do not go into the head as deeply as the ones I took out.. would you think that I'm going to have to lessen my total timing
or increase it.