Spark Plug Gaps

[Deleted member 20330]

Recently, I purchased Autolite APP104 spark plugs for a Gen 2.

After a bit of searching, I've noticed there's a wide range of opinions regarding the gapping of spark plugs.

The first disagreement is whether or not the gap on a spark plug should be changed out of the box. From experience, gap specs exist for a reason and manufacturing and handling processes can affect those gaps. But I've also read platinum plugs can be easily damaged during gapping even when exercising care.

The second disagreement is if the gap should be changed out of the box, what should it be changed to ? For the APP104 on a Gen 2, I've seem numbers from .040 - .054.

Any thoughts ?

 

[Right on the Mark]

.054

 

[driller]

.054

Stock/platinum... 0.054

Mildly modded/copper... 0.048

Heavily modded/copper or platinum... 0.035 to 0.040

 

[Right on the Mark]

Stock/platinum... 0.054

Mildly modded/copper... 0.048

Heavily modded/copper or platinum... 0.035 to 0.040

OP did say they have a Gen2! LOL Plus we can guess the OP is stock(never mentioned mods) and stated platinum plugs by their post.

 

[turn_on68]

So .54 for double platinum?

 

[Right on the Mark]

So .54 for double platinum?

.54 impossible LOL .054 yes. The .048 for coppers because as they wear the gap widens. I still set my coppers at .054 because I change them out at sooner intervals.

 

[turn_on68]

Yes .054 Thanks.

 

[Sapperfire]

The rule of spark plugs is simple. Never trust someone else to do your job correctly. Always check the gap

 

[turn_on68]

I always check the gap even on my mower engine.

 

[driller]

OP did say they have a Gen2! LOL Plus we can guess the OP is stock(never mentioned mods) and stated platinum plugs by their post.

Just referencing why he may have seen numbers from 0.040 to 0.054.

Gap should still be checked on all new plugs, even platinum.

 

[Deleted member 20330]

OP did say they have a Gen2! LOL Plus we can guess the OP is stock(never mentioned mods) and stated platinum plugs by their post.

Right on the Mark,

No mods. Just OEM.

The only performance product added to the car was a K&N air filter.

 

[Deleted member 20330]

To those who are thinking of changing their own spark plugs for the first time ...

The out of box gaps from an Autolite APP104 ranged between .038 and .049.

So yes, gap it yourself.

 

[Right on the Mark]

To those who are thinking of changing their own spark plugs for the first time ...

The out of box gaps from an Autolite APP104 ranged between .038 and .049.

So yes, gap it yourself.

Also make sure you torque the sparkplugs to correct specs. There are not alot of threads in the alum head. Alot of peeps have problems with blowing plugs out of head from peeps not tightening to correct specs.

 

[turn_on68]

And a Gen 2 '98 would be 12 Ft lbs ?

 

[keVIIIn]

I've never dealt with changing plugs on aluminum head engines before..everything has always been cast iron, I'm going to change mine soon..any tips or hints on spark plug removal to prevent damage to threads while removing them? I've heard people say to crack loose the plugs and put wires back on, start it and rev it for a few seconds to blow any carbon that came loose out the exhaust. Does this sound plausible?

 

[Right on the Mark]

I've never dealt with changing plugs on aluminum head engines before..everything has always been cast iron, I'm going to change mine soon..any tips or hints on spark plug removal to prevent damage to threads while removing them? I've heard people say to crack loose the plugs and put wires back on, start it and rev it for a few seconds to blow any carbon that came loose out the exhaust. Does this sound plausible?

There are really no problems removing the plugs on a 4.6L 4V. The 3V engines are different story.

 

[Robot]

I've never dealt with changing plugs on aluminum head engines before..everything has always been cast iron, I'm going to change mine soon..any tips or hints on spark plug removal to prevent damage to threads while removing them? I've heard people say to crack loose the plugs and put wires back on, start it and rev it for a few seconds to blow any carbon that came loose out the exhaust. Does this sound plausible?

No sense going through that procedure as it can be done after the new ones are in. Lubricant on threads, finger twist on so you can feel any resistance. There should be no resistance at all until the ring makes contact. Tighten just tight enough so they can't back out. Almost forgot, cold engine is much easier. I just did mine yesterday.

 

[NetKeym]

I've never dealt with changing plugs on aluminum head engines before..everything has always been cast iron, I'm going to change mine soon..any tips or hints on spark plug removal to prevent damage to threads while removing them? I've heard people say to crack loose the plugs and put wires back on, start it and rev it for a few seconds to blow any carbon that came loose out the exhaust. Does this sound plausible?

Just don't over-tighten them when you put them back in; aluminum strips out MUCH easier that cast iron....

 

[Right on the Mark]

Just don't over-tighten them when you put them back in; aluminum strips out MUCH easier that cast iron....

Yeah that's why Torque specs for plugs are very important! You only have 4 threads in the alum head. And this is why plugs pop out of the heads. People over tighten and pull out threads, then out comes the plug boom.