'94 Ford 4.6 Spark Plugs

[Fifth87]

Just purchased a '94 Grand Marquis, story and pics to follow at a later date.
I am uncertain if the plugs have ever been changed, and with all I have heard/read about the 3 piece plug, threads pulling out or ejection, I am electing to pay to have this done. My question is this: Did Ford ever modify the plug design, so going forward I can change them myself without fear of breakage?

 

[melk]

it’s generally easier to change plugs on the 4.6 than the 5.4

 

[SwampSurvivor]

That's going to be a 2 valve 4.6, so it doesn't have the 3 piece plugs that break off in the head.

It has the threads that strip out. They do that because the factory torque spec is way too low, then they start to back out and just take the 3 threads when they eject. The solution is to slightly overtorque.

 

[wtd]

Just purchased a '94 Grand Marquis, story and pics to follow at a later date.
I am uncertain if the plugs have ever been changed, and with all I have heard/read about the 3 piece plug, threads pulling out or ejection, I am electing to pay to have this done. My question is this: Did Ford ever modify the plug design, so going forward I can change them myself without fear of breakage?

That car should have a conventional style plug and not the three-piece ones used in the 3 valve engines which were used in the mid 2000's.

 

[Cujet]

You should have no problem changing the plugs on that engine. Nothing special about it. The spark plugs are not the ultra-long versions found in the early 3 Valve versions of that engine. While this pic may not be the exact year you have, it is very close and it does show the conventional spark plug bores you have.

 

[D60]

~28 ft lbs. It's easy. Your horror stories are of the 3V

 

[thastinger]

~28 ft lbs. It's easy. Your horror stories are of the 3V

That torque spec has changed a lot over the years. I have a 98 5.4 2V and when I first started changing plugs the spec was 14ft-lbs with anti-seize, the Ford eventually changed it to 28-32ft-lbs without anti-seize. I've never chucked a plug from either 2V 5.4 we have(x2), even when I was using the 14ft-lb spec.

 

[ARCOgraphite]

Given mileage and year, this will likely be (at the very least) the third set of plugs going in.

I would not run a fine tip IR on a waste spark share coil pack ignition. This is a good application for Denso TT- at least on the "wrong fire" plug. IIRC these 4.6 came with two different plug P/N from factory for specific cylinders - possibly Pt tip/gnd