Hey guys, I'm replacing my sparkplugs tomorrow and I'd like to make sure I get them indexed towards the intake valves. I just wanted to verify that the intake valves are on the inboard side of each cylinder, correct? Thanks.
Sparkplug Indexing
- Thread starter pridemore54
- Start date
Follow up question, I see conflicting theories about whether the grounding strap should be pointed towards the intake or exhaust valves. Can anyone clear it up which is better? To me it only makes sense to have the gap towards the intake for a better burn, but some say the fuel will ruin the plug quickly.
How do you do that? When you torque the plug down it is what it is.
It can be done by adding crush washers to change where it indexes.
I've never seen any evidence that it actually helps. Today's combustion chambers swirl, tumble, even shake, rattle and roll the intake charge so indexing isn't needed.
I've never seen any evidence that it actually helps. Today's combustion chambers swirl, tumble, even shake, rattle and roll the intake charge so indexing isn't needed.
I've never done indexing and never had an issue. I also haven't seen proof in a street car indexing makes a difference. Making sure you have the right gap and the plug is seated all the way down is what is most important.
Indexing isnt needed on a modern car. Flame front propagation on our cars isnt dependant on plug indexing. The pent roof design of our combustion chambers just needs the spark in the center. On a top fuel or funny car perhaps
Maybe I'm wrong about this so someone please correct me if so...
Our plugs don't have straight cut threads and a washer but are instead the tapered thread style. So if you use spacers to index the plug then you will not be getting full/proper thread engagement and run the risk of blowing the plug out.
Our plugs don't have straight cut threads and a washer but are instead the tapered thread style. So if you use spacers to index the plug then you will not be getting full/proper thread engagement and run the risk of blowing the plug out.
Understood. I know it really won't make much of a difference. Im just hoping to possibly see a little better drivability in the lower rpms. My drive way is a son of a bitch to back out of and sometimes results in bogging the engine a little.
I definitely hadn't thought of that. I will look into it before continuing.
What plugs are you running? Maybe try a different plug.
Not sure, still got the plugs from the last owner. Part of the reason I'm doing this. I went with brisk racing plugs. Can't remember which model off the top of my head
I have not tried those plugs, but my experience with colder plugs is that they act funny when the car is not fully warmed up and at low rpms. If these plugs do not do the trick for you not sure how much boost your pushing but if its close to stock maybe go back to stock plugs.
Indexing spark plugs?
That's a new one for me.
That's a new one for me.
You're way overthinking this one. Indexing your plugs isn't going to give you better drivability in low RPM situations. If there's an improvement to be made there, it's in your tune.
+1
A photo of a properly indexed spark plug.
.
?????????????????????????????????
Looks like that combustion chamber is a couple of valves short.
What he is referring to is how the plug seals at the head. The GT500 and probably most spark plugs today use a tapered seat. The other type uses a crush washer (also referred to as gasket) and is found in most of the older spark plug designs. The crush washer thickness is what allows one the ability to index the plug. I'm not sure how you would do that with a tapered seat plug. Which was his point as well. You'd probably have to go through a lot of different plugs to get the electrode indexed where you want it with the tapered design since there is no way to "shim" it.
Users who are viewing this thread
