REVISED SPARK PLUG USAGE for 4.6L

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Bill G-Man:

My 4.6L SOHC V8 originally uses the plugs on the left (AWSFA-12C) for use with the custom tune.

I then switched to the AGSF-12FM1s (on the right) which, IIRC, are stock plugs from late model Lightnings. Even though there are more threads, it fits just the same on the heads with only a few threads.

THe 2004 Cobra uses:
AGSF-22FM1 (1 heat range hotter than the AGSF-12FM1s that I am using).

Based on the way Motorcraft plugs are numbered... the 4.6L DOHC V8 on the 03-04 Cobra would take the plugs on the RIGHT of my pic w/o any problems.

I am not saying the AGSF-12FM1/22FM1 plugs will eliminate the ejection problem, but I'm just saying they will fit the 4.6L SOHC V8 heads regardless of how they look. From the sound of it (04 Cobras using AGSF-22FM1), the Marauders should be able to use the same ones. These plugs are of an iridium design if I'm not mistaken. Platinum plugs are usually just copper-style plugs with a platinum slug on the electrode. The 12FM1/22FM1 Motorcraft plugs have TINY electrodes - copper or platinum would easily wear out... leaving the choice material as being of an iridium variant. At $4/ea they are a much better deal than Denso.
 
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metroplex said:
Bill G-Man:

I am not saying the AGSF-12FM1/22FM1 plugs will eliminate the ejection problem, but I'm just saying they will fit the 4.6L SOHC V8 heads regardless of how they look.
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Yes, that's exactly my point though. Some of the other posts in this thread seemed to suggest that going with these other plugs would somehow eliminate or prevent the alleged possibility of the plugs getting pushed out of the threaded holes of the cylinder heads on our Marauder engines. However, if the cylinder heads on our engines are only going to occupy and use 6 threads or less of on any sparkplug that's used, then simply by using a plug that offeres more threads than the cylinder heads can use will NOT eliminate the plug from dislodging from the heads as it was implied.

You can install a sparkplug that has 25 or 30 threads on it into the cylinder heads on your engine, but that doesn't mean that it will be held in the head anymore securely than the original plug with 6 threads will be IF the cylinder heads don't have anymore than 6 threads machined into them. However, all of this is conjecture until one of us can get a good enough look at our cylinder heads while they've been taken off of the engine block to actually see for ourselves exactly how many threads there are in these cylinder heads of ours.
 
I went with the AGSF-12FM1 plugs because they were the right heat range, and they're supposed to be an improvement over coppers.

My AWSFA-12Cs were worn out at the electrode. I expect only 20k-25k miles out of them, and would prefer longer-lasting performance iridium plugs.

I always use anti-sieze on the threads, and torque it to the FSM spec (15 ft-lbs).
 
Just thinking out loud

Just thinking out loud...

"IF" the issue is the plug not seating correctly in the cylinder head, couldn't that be a source of blow by or at least a "leak" therefore not allowing for proper combustion? If that is the case, couldn't that cause the darkness on the plug?

I believe the spark plug holes are tapped all at once when they are machined. If the number 7 tap was off, having a little bit more thread on the spark plug could make up the difference. It may only be the only one extra thread that is needed to properly seat.

Anyway just my .02 worth. :confused:
 
cyled said:
I believe the spark plug holes are tapped all at once when they are machined. If the number 7 tap was off, having a little bit more thread on the spark plug could make up the difference. It may only be the only one extra thread that is needed to properly seat.

Anyway just my .02 worth. :confused:
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You're talking my language, because I happen to work in a room that's located inside of a machine shop. A rather huge machine shop at that. I think you're missing the point. How many threads in a hole being tapped with the same thread pitch as several other threaded holes are is NOT determined by how accurate the tap is, nor how worn it is, but is determined by how deep the hole is. For example......I know by looking at the sparkplugs that are used in our Marauder engines that the threaded holes in the cylinder heads are 24 threads per inch. So if the hole that's being tapped is only a quarter of an inch deep, then there will be 6 threads tapped into that hole regardless of what condition the tap is in that's being used as long as you're using a tap that's made with 24 threads per inch. So as long as the medal where the hole is that's been drilled is one quarter of an inch thick, there will only be 6 threads in that hole as long as the intended tap of 24 threads per inch is used. It would have nothing to do with the tap being "off" as you've implied. And if the wrong tap was used to begin with (such as one of 20 threads per inch) then the car would've never gone off the assembly line since nobody would've ever been able to thread the intended sparkplug into that hole because the threads would've been different.
 
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From all the cases I've heard where the plug(s) ejected out of the motor (taking out a COP coil or two), the threads on the head were GONE (left with the plugs).

Experts have analyzed this and blamed it on the low number of threads holding the plug (like 2-4 threads on the head).

This is more common on trucks (5.4s) for some reason, and detonation at load is one major cause of this problem.

A solution is to use Timeserts. Theyre so good that people often contemplate installing them on all 8 plug holes.
 
metroplex said:
From all the cases I've heard where the plug(s) ejected out of the motor (taking out a COP coil or two), the threads on the head were GONE (left with the plugs).

Experts have analyzed this and blamed it on the low number of threads holding the plug (like 2-4 threads on the head).

This is more common on trucks (5.4s) for some reason, and detonation at load is one major cause of this problem.

A solution is to use Timeserts. Theyre so good that people often contemplate installing them on all 8 plug holes.
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You must mean "slimserts". We use them where I work. But the ones that you're talking about must make the hole deeper by offering more threads than the original hole did. However, I've never seen slimserts being used to elongate a hole, but simply to repair a hole, or prevent it from having to be re-machined in the first place in the event of thread damage.

But either way,the fact remains that using a sparkplug that has more threads on it than the cylinder head holes do, will not be of any benefit in the prevention of dislodging the plugs from the holes.
 
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BillyGman said:
You're talking my language, because I happen to work in a room that's located inside of a machine shop. A rather huge machine shop at that. I think you're missing the point. How many threads in a hole being tapped with the same thread pitch as several other threaded holes are is NOT determined by how accurate the tap is, nor how worn it is, but is determined by how deep the hole is. For example......I know by looking at the sparkplugs that are used in our Marauder engines that the threaded holes in the cylinder heads are 24 threads per inch. So if the hole that's being tapped is only a quarter of an inch deep, then there will be 6 threads tapped into that hole regardless of what condition the tap is in that's being used as long as you're using a tap that's made with 24 threads per inch. So as long as the medal where the hole is that's been drilled is one quarter of an inch thick, there will only be 6 threads in that hole as long as the intended tap of 24 threads per inch is used. It would have nothing to do with the tap being "off" as you've implied. And if the wrong tap was used to begin with 9such as one of 20 threads per inch) then the car would've never gone off the assembly line since nobody would've ever been able to thread the intended sparkplug into that hole because the threads would've been different.
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Good point.. that is why it was only worth .02.. probably should give back .01... :D
 
cyled said:
Good point.. that is why it was only worth .02.. probably should give back .01... :D
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hey, it's all good, because discussions like these help to deepen the understanding of us all about our cars.
 
That's a negative. I'm talking about Timeserts. They're a well known product for repairing ejected spark plug holes on MODULAR heads.

Look it up. They're like helicoil inserts, but they're called Timeserts.
 
metroplex said:
That's a negative. I'm talking about Timeserts. They're a well known product for repairing ejected spark plug holes on MODULAR heads.

Look it up. They're like helicoil inserts, but they're called Timeserts.
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got it......I think that different companies who have these products come up with different brand names in order to make their product sound exclusive........."Timeserts"......"slimserts"........
 
I can see how the extra threads would help if the tapped out portion of spark plug hole was too high. It's like they tap the whole depth of the hole and then come back and drill from the top to clear it. If they drilled too shallow, then the spark plug would stop where the threads stop, instead of seating on the proper area.

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sparkcomparo.jpg

So, you can see that if you put the plug on the left in the bottom hole, it would stop before seating correctly.
 
You're correct, but on the 4.6/5.4 2V heads, your top diagram is how the heads appear.

More threads on the plugs are fine because the taper seats at the same depth.
 
Thanks very much. That was very revealing. the marauder cylinder head has only four threads, and the SOHC cylinder head has five threads, and there's a smooth part of the bore immediately following the threads that the original sparkplug design will match up perfectly with. therefore what I suspected is true......the original plugs are better equipped for a perfect fit than these other plugs that have threads all the way up to the tapered shoulder. If you look at that video a few times, it becames obvious that the original plugs will provide a better seal than those other sparkplugs will since they fit the cylinder head hole more precisely. I figured there had to be a reason why Ford called out for the plugs that our Marauders came with from the factory. So as for me, I'm glad that I stayed with that plug design.
 
I figured there had to be a reason why Ford called out for the plugs that our Marauders came with from the factory. So as for me, I'm glad that I stayed with that plug design.
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That's funny because Ford calls for AGSF-22FM1 on the 04 Cobra. Unless the heads are radically different between the 03-04 Cobra and the 03-04 Marauder, there should be no difference in sealing between the two different plug designs.

There was a significant concern about the full threaded plugs sealing well on our 4.6/5.4 SOHC heads. Truth be told, if you mic the plugs or use a caliper, you will find that either plug will seal properly on the 2V heads. It just looks like the full threaded plug won't seal.

I recommend you take precise measurements between the plugs to figure things out. A bore scope gives you a good idea of what it looks like, but the only way to tell for sure is to use a caliper or micrometer.
 
metroplex said:
you will find that either plug will seal properly on the 2V heads. It just looks like the full threaded plug won't seal.
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That might be the case, but even if it is, I want to reurn to my original point in this thread......which was the fact that since there are merely four or five threads in the sparkplug holes of the Marauder cylinder heads as "Killed Kenny" has proven with his video, then there's absolutely no need, nor advantage by going with those plugs that have more than six threads on them. And there were those who were claiming that there was an advantage earlier in this thread. And that just is NOT true. I'm sure that it was an honest mistake, and that those individuals meant well, but the fact is that having 6 threads on the plugs that are called out for is just fine, and there's no sealing advantages offered by the plugs with 10 threads on them.
 
plugs

I believe that the AGSF-32W-MF6 is a sparkplug for a V6 engine (SABLE AND TAURUS). The 03' and 04' Platinum Marauder plug is AGSF-32W-MF4. At least that is what I see from the Motorcraft online catalog. Is the information incorrect in the online catalog?
Howard


schuvwj said:
16856 2003 4.6L 4V MUSTANG MACH I, MERCURY MARAUDER, REVISED SPARK PLUG USAGE.
SOME 2003 MERCURY MARAUDER, MUSTANG MACH I, LINCOLN AVIATORS WERE BUILT WITH 4.6L 4V ENGINES USING SPARK PLUG PART NO. (AWSF-32E-M (F6LE-12405-AC) AND
SPARK PLUG PART NO. AGSF-32W-M (XS2E-12405-AB).
WHENEVER THE SPARK PLUGS REQUIRE REPLACEMENT FOR SERVICE, USE PART NO. AGSF-32W-MF6 (XS2E-12405-AB) ALSO, THE REPLACEMENT SPARK PLUGS ARE OF THE FULL THREAD DESIGN AND ARE RECOMMENDED FOR ALL APPLICATIONS. OWNER GUIDE AND SERVICE PUBLICATIONS ARE BEING UPDATED TO REFLECT THIS CHANGE.

My MM came with AWSF-32E-M from the fatory and the full threaded replacement plug is AGSF-32W-MF6.
This would explain why my #7 spark plug gets motor oil around it in the plug hole and fouls the plug. At the factory the counter bore for the plug seat was machined too deep and the plug bottms on the threads before it properly mates with the Cly. head seat.
I see the IT20's have threads all the way up the plug seat so those plugs are all right!
Dennis can you tell us what the cooler plug number with full threads we should use for Motocraft AWSF-A12C?

Thanks!
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schuvwj said:
16856 2003 4.6L 4V MUSTANG MACH I, MERCURY MARAUDER, REVISED SPARK PLUG USAGE.
SOME 2003 MERCURY MARAUDER, MUSTANG MACH I, LINCOLN AVIATORS WERE BUILT WITH 4.6L 4V ENGINES USING SPARK PLUG PART NO. (AWSF-32E-M (F6LE-12405-AC) AND
SPARK PLUG PART NO. AGSF-32W-M (XS2E-12405-AB).
WHENEVER THE SPARK PLUGS REQUIRE REPLACEMENT FOR SERVICE, USE PART NO. AGSF-32W-MF6 (XS2E-12405-AB) ALSO, THE REPLACEMENT SPARK PLUGS ARE OF THE FULL THREAD DESIGN AND ARE RECOMMENDED FOR ALL APPLICATIONS. OWNER GUIDE AND SERVICE PUBLICATIONS ARE BEING UPDATED TO REFLECT THIS CHANGE.

My MM came with AWSF-32E-M from the fatory and the full threaded replacement plug is AGSF-32W-MF6.
This would explain why my #7 spark plug gets motor oil around it in the plug hole and fouls the plug. At the factory the counter bore for the plug seat was machined too deep and the plug bottms on the threads before it properly mates with the Cly. head seat.
I see the IT20's have threads all the way up the plug seat so those plugs are all right!
Dennis can you tell us what the cooler plug number with full threads we should use for Motocraft AWSF-A12C?

Thanks!
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I use 12 C on NA Marauders 22C on high Boost Marauders Denso IT 20 for NA and IT for Blown
 
hbarrett said:
I believe that the AGSF-32W-MF6 is a sparkplug for a V6 engine (SABLE AND TAURUS). The 03' and 04' Platinum Marauder plug is AGSF-32W-MF4. At least that is what I see from the Motorcraft online catalog. Is the information incorrect in the online catalog?
Howard
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The F6 or F4 has no bearing on the plug design.
It only dictates if the plugs are packed in a box of 6 (F6) or 4 (F4).
Dealers will probably buy the 6 pack, instead of the 4 pack, just because of the amount of space they have.
One slot for one part.

A Motorcraft Dealer would sell you the AGSF32WMF4 x2 for a Marauder,
and a AGSF32WMF6 for a Sable or Taurus.
If he only carried the F6, he would have to give you 2 loose plugs to make 8...
 
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