This is from "How To Build Max-Performance 4.6-Liter Ford Engines"
by Sean Hyland

- Let engine cool, the primary cause of damaged threads on the aluminum cylinder heads is trying to remove the plugs when the head is still to hot. The aluminum material expands when warm, and the plug is going to take more turning effort to loosen than when the head has cooled.

- SparkPlugs for a 5.4L engine are to be torqed to 13 lb-ft

- Indexing the spark plug ground strap seems to provide some power.
In the case of the 2-valve engine, the ground strap shoud face the wall of the combustion chamber, aiming the spark, as it were, towards the far side of the combustion chamber

 

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- Indexing the spark plug ground strap seems to provide some power.
In the case of the 2-valve engine, the ground strap shoud face the wall of the combustion chamber, aiming the spark, as it were, towards the far side of the combustion chamber [/B][/QUOTE]


WHAT does that mean?
Thanks

 

Take a marker and mark on the side of the plug where the gap is. When you tighten the plug, you try and make that mark (the ground strap) face the engine.

 

Thanks, It will be hard to see down into the abyss to make sure.

Oh well one more excuse to pull the plugs.

 

I have this book at home so I will check on it later but... As far as I know there isn't a way to index tapered plugs. Does he mention exactly how to index them?

Even if it is possible I would think this would only be feasible on a race motor for three reasons:

1. We are talking a max of 5hp.
2. We have enough trouble keeping our plugs in the heads.
3. This book is about building race motors and I'm almost positive that this information was taken from the context of building a 1000+ hp 5.4. (I've read the book a couple of times )

--Steele

 

This data is on page 75 and is general info for both the 4.6 and 5.4 engines.

How much have some of use payed for an additional 5hp? Here you can get it for free!

I would think you could place the plug in the sparkplug socket, then mark the extension based on the position of the plug in the socket. Then just tighten till the gap is facing the engine.

 

I would think you could place the plug in the sparkplug socket, then mark the extension based on the position of the plug in the socket. Then just tighten till the gap is facing the engine. [/B][/QUOTE]

that is what i was thinking

 

Indexing a spark plug which has metal threads into a head that is aluminum sounds really screwy to me.

If you torque them to a spec or do as most people do by getting them snug and then 1/8 to 1/4 turn there is NO WAY your going to index the plug with out doing DAMAGE to your head.

I would HIGHLY advise AGAINST even thinking about indexing a plug or that 5hp “slightly possible” gain if that, could cost you well over $2,000 for heads and the labor if not a lot more…

 

01XLT -

I am so glad you posted that. For a minute, I thought I was the only one who was thinking this doesn't sound like a great idea...

 

To index a spark plug correctly, you tighten the plug to spec's and make a note what postion the "ground strap" is at.

Then you use different thickness "washers" to obtain the correct postion. There are kits available

 

That makes a lot more sense.

 

Ahhhh, the master chimes in and I now have another lesson under my belt…

That makes a lot of sense to use washers or varying thickness but man that must be a real pain in the butt.

Since I am in class who exactly indexes spark plugs like that? Do they do that in professional drag racing? Nascar? Other professional racing circuits?

 

its a real PITA

but you be surprised whom might do that!
Especially people that run 11's more than once and don't need a nitrous bottle to do it

 

Indexing is not easy on a 'regular' engine. It would be a 'nightmare' on our engines, certainly while the engine is in the truck.

There are special index washers used to adjust for where the ground electrode end's up; which way the 'gap' is facing. Do you really want a washer(of undetermined thickness) taking up the spark plug thread's space......in the earlier heads that only have 4-5 spark plug threads in them? Think about it--how many threads are holding the plug in with a tapered(if in fact, tapered index washers are available?) washer under the plug???

The correct amount of 'tightness' for our steel(shell) plugs in our aluminum heads is "finger-tight then 1/16th of a turn more and no more. Do you really want to continue turning the plug tighter, 'stretching' the head's aluminum threads just to align/index your plugs? IMHO, overtightening the plugs 'may'(?) be the culprit for blowing a plug out of the head as much as undertightening.

Dan

 

I don't think anyone needs to index their sparkplugs. If you think its important buy a set of the Bosh Platinum’s with the 4 electrodes’, then you wouldn't have to worry about. Or if they don't make them for your vehicle, maybe an Iridium type which has a smaller electrode that would not get in the way of the flame front.