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After screwing up the first 2 attempts myself I decided to show how to properly use this kit for repairing spark plug threads on the modular heads.  For those that insist on doing this in the car scroll down to the last picture.  This help guide is supplemental to the instructions provided in the kit which can be found here.  I personally feel that this is the best kit for the DIY or small shop to use.  If installed properly they will never come back out and there is no problem with heat transfer from the plug to the head.  If you question the ability of steel to be installed in an aluminum head properly and transferring heat take a look at the steel valve seats that are only held in the aluminum head with a press fit and think of how hot the exhaust valve gets.

Picture of complete kit.


Step 1 counterbore head until proper depth.

(Counterbore tool)



This is the most important step I learned especially if you are repairing a Romeo head.  If you do not get the counterbore depth correct you will have a serious repair on your hands.  Once these inserts are installed they do not want to come back out.

This picture shows the incorrect counterbore depth.  This will happen quite easily on the Romeo head since it has such a deeper area to be cut away.  Trust me I did it wrong twice according to the instructions provided.  These next two pictures are the most important and missing from the kit instructions.


This is the correct counterbore depth, you can see the full cutting edge of the tip protruding into the chamber.  This is what the entire kit is based on for locating the insert.  Get this wrong and everything else will be wrong.


Next step is to ream the head with the supplied reamer.



And it needs to be done to this depth.



Then you use the supplied tap and tap the hole for the insert threads.



Install the insert into its special setting tool.



Use the driver to mechanically set the threads of the insert into the head.




A properly installed insert.
Install the insert into its special setti


An improperly installed insert which will happen with the wrong counterbore depth as was shown above, you can see the insert is about 3 threads shy of reaching the chamber.  The car will run with this and many are out there running this way right now I imagine.


g tool.
Shavings removed from just one installation.  If you do this on the head in the car this is what you will have to deal with.  With the Romeo heads it is approximately the volume of a spark plug, the amount from a Windsor will be slightly less.


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