Dorman Cylinder Head – Spark Plug Thread Repair Kit Fail?
DennisB WiseAutoTools.com © Summary: Help is here for cases where the Dorman Cylinder Head Repair has failed and has made the spark plug hole too big to fix with a parts store kit. We get calls frequently from vehicle owners and auto repair shops that are looking for a spark plug thread repair that works when a Dorman spark plug thread (cylinder head) DIY repair kit has failed. Napa calls it the Spark Plug Rethreader Kit and Advance Auto Parts calls it “Help Cylinder Head Repair Kit”. The Dorman cylinder head thread repair uses a newer 3V type spark plug and boot with a tapered adapter that is threaded in without any preparation. That’s right, no threads are made other than the ones made by screwing in the tapered self tap adapter. Sounds easy… no drilling, it’s inexpensive, it’s readily available at many parts stores throughout the country and there’s no mention of possible compression loss from a bad fitting seal? Don’t even worry about using a matching spark plug?! Whenever something sounds to good to be true – it usually is. The convenience and wide application of this inexpensive spark plug thread repair kit is the reason that so many are sold. The downside is; if it works at all, is that when the Dorman thread repair kit fails, it usually breaks the coil (again) and leaves the spark plug hole even BIGGER than before. Good News! We have the fix.
Time Sert makes two kits for 2 and 4 valve engines that can work when parts store type kits, including Dorman fail. The Time Sert 5553 works on spark plug holes that are .66″ or smaller. The Time Sert 5600 works on holes all the way up to .73″. For Ford 3-Valve engines Time Sert doesn’t currently have an oversize kit available, but Calvan does.
Calvan is also sold as the Snap On Blue Point FRT12 – Calvan 39300 is the oversize repair for 3-V Fords. The 3-Valve engines are suppose to have the type of spark plug that’s used in the Dorman kit for everything. They have long electrode shield. The Dorman kit uses it for any application 1995 or 2015.
Time Sert and Calvan uses a reamer (like a drill bit) that removes the damaged portion of the hole. Then a thread tap is used to make solid threads to accept the bushing type insert. Both brands use an installer to put the insert in. With Time Sert the installation driver spreads the bottom of the insert locking it into place. Calvan has a large lip on the top that allows it to tighten down like a bolt. We sell many of each brand and can help determine which spark plug thread repair kit is best for your particular application. Visit product listings at WiseAutotools.com or DenLorsTools.com or want to research a little more? See our article on Ford Spark Plug Blowouts or- call us at 800-734-8665 or 800-734-8665.