Cman

I'm on another MB (local Mustang board) and currently I'm in a bit of a disagreement with someone else there.

The topic being discussed is about torquing spark plugs. This person claims that he torque his plugs with a torque wrench and that he notices a difference vs. tightening them up normally with a ratchet or wrench (which is what I do).

Now I don't have a problem with him tightening his fasteners (or plugs) with a torque wrench, all the more to him. As you all know getting a torque wrench in our cars to tighten spark plugs is next to impossible so I do it by feel. I can tell when I've tighten the plugs enough so that it's not too tight yet is not loose to blow out the cyl. but he insists that you see a gain of 1-5hp by torquing your plugs with a torque wrench.

He even says you can see the difference between properly torqued plugs vs. properly tightened plugs on a ocilliscope and I'm saying no way.

This guy must be older than me, the last time I used a scope for any car was going back to the mid 80's, I mean who T F uses a scope anymore?? All the shops that I've visited that had one is sitting in a corner covered up with 15+ years of dust on top of the cover.

From what I remember you use a scope to find problems with your ignition system and look for weird firing patterns especially on cars that have points and condensor (what are those again?????) but to tell the difference between torqued plugs and properly tighten plugs???? I think he's whacked.

So who's right???

Tony

shoebox

Maybe the difference between a loose plug and a torqued one would be apparent, but not one that was sufficiently tightened without a torque wrench, IMO.

Everyone is entitled to their opinion. It's not really worth arguing about.

Dave '97 Z28 M6

I could imagine that perhaps how the electrodes are lined up in the combustion chambers might have a small effect; but as for the torque... I'd think that once they're snug, that's as good as it gets.

Ok4thGen

Exactly, i think what your talking about is considered index'ing

revtime

Indexing the plugs might show an increase. As long as the plug is tight you would not be able to tell a difference.

5 HP from just screwing my plugs in tighter? Let me go get my wrench.

2000GTP

Its possible you are arguing with a young guy, alot of high schools, colleges, and tech schools have them "old" scopes lying around.

Cman

You do that, and report back here with your findings.

Tony

Eff

A few years ago I dynoed a LT-1 (4 baseline runs) spent 3-4 hours with an index gauge and indexed the plugs. and saw 1-2 hp and torque increase, wich could easily have been the temperature dropping a few degrees or the car cooling off. My conclusion. unless you are looking for hundreths of a second indexing spark plugs is a waste of time. BTW. every spark plug is different. the threads do not start at the same place relitive to the ground stap on the plug. torque alone cannot be used to index plugs, you have to torque them into an indexing gauge first.
and If you overtorque the plugs to the point where they crack you'll lose alot more than 5hp!

MyShibbyZ28

Let the man think what he wants to think, as everyone is entitled to his or her opinion. Personally I think once the spark plug is tight, it is tight. No need to torque it.

Cman

Looks like I'm done discussing this topic with him, for some ****s and giggles take a look here:

It gets interesting around page 2.

Tony