Spark Plug came out - helicoil

[mremington]

Long time reader first time poster here. I purchased my 300a from MartyO about 3 years or so ago with 35k on the clock. Recently had random misfire issues and yesterday it misfired constantly at a stoplight then sounded awful as i limped back home the next mile. Pulled the coils and a plug came out along with the coil. The plug was embedded up in the boot. When I went to put a new plug in it wouldn't grab onto any threads. Got a helicoil kit and have used the tap tool with a lot of axle grease per Martys recommendation to ream out a newer thread and catch the shavings. I'm just about done with that as I barely see anymore metal when I pull the tool back out. However I have a question about the actual insertion of the new thread.
After I insert the helicoil and spark plug together does it simply tighten down until snug and that's the right depth in the head or do I need to gauge the depth to make it even with the old threads / other plugs? If so, once its even height-wise with the other plugs, I would then hammer it in place with the expansion tool? Also, should I use antiseize on the plug?
Any advice or hints would be greatly appreciated, thanks!

[Ourobos]

Don't use a helicoil, use a timesert.. And you will put loctite on the thread of the timesert, and then it will lock into the head for later plug removal.

[RubberCtyRauder]

+1 timesert

[mremington]

Does it matter that I've already started with the helicoil kit and used the tap tool to re-thread?

[RubberCtyRauder]

Timesert stronger. They make an oversize one for holes previously helicoiled. Try what you got since you started it already. If no work then can still do timesert

[FordNut]

Put anti-sieze on the plug threads and loctite on the insert threads. Screw it in and let the loctite set, the remove the plug and use the expansion tool. Then reinstall the plug.

If you get impatient and don't let the loctite set, the insert will come back out with the plug.

For correct depth, I would screw it in until the tip of the plug is even with the rest of them. I just did them in my lawn mower and tightening until the plug bottomed would have ended up with the whole plug down in the cylinder.

[ctrlraven]

Spark plug tourqe is 11 ft-lbs or 132 in-lbs. If you use anti-sieze on the plug threads, only a light dap is needed.

03 heads only have 4 threads to grab the plug.

[mremington]

Thanks everyone, I'll try to set this thing in there later tonight and see what happens. I greatly appreciate all the help and feedback. And only 4 threads on the original? Really Ford???

[mremington]

Another question. Should I crank for a few seconds without the plug in to blow any extra shavings or debris form the cylinder?

[Zack]

Thanks everyone, I'll try to set this thing in there later tonight and see what happens. I greatly appreciate all the help and feedback. And only 4 threads on the original? Really Ford???

26 Pounds of boost here with 4 threads and zero problems

[Turbov6Bryan]

Another question. Should I crank for a few seconds without the plug in to blow any extra shavings or debris form the cylinder?

You should be doing this with all 4 valves closed

Use a smaller air tube and blow air into the cylinder to vent out any debris the grease didn't catch

[mremington]

Got the coil in and hammered down. Has done good so far. Gave it a few hard runs and a nice long trip around town, and no problems yet. Gonna pull the COP and make sure the plug hasn't moved and then do the other 7 since I've been told you should do all 8 plugs at once. As it stands I think we're all good. Thanks to everyone that responded, always nice to have the opinion of some experts! Happy Easter Guys!!

[FordNut]

Personally I wouldn't mess with the other 7. That's 7 more opportunities for something to go wrong.

[mremington]

Oh well, too late for that. A couple of the other plugs, especially drivers side closest to the firewall looked dirty and burnt. Cleaned the IAC and MAF too. Still a very slight miss at idle in park occasionally, can kinda hear a little tuck tuck tuck sound from the passenger side exhaust when it occurs. Does that indicate which side of the engine the misfire is coming from?? I'm going to get 7 new coils from rockauto this week and swap the other old ones. DG543 correct? She does pull much stronger and smoother than before! No more ticking sound either, which I assume was that one plug working itself slowly back out.

[ctrlraven]

The part number for a set of 8 Motorcraft/Ford Racing coils is M-12029-4V.