screwed up thread in sparkplughole

onno wielinga · Post by **onno wielinga** » Wed Jan 04, 2006 7:48 pm

i have screwed up the thread in the head, when putting in a new sparkplug. the first 3 "lines" are damaged. 80/90% is still intact.
i am sure i can repair this by taking off the head and screw in a sparkplug from the inside bit by bit and back and forth.

i would like to be able to repair this without taking off the one head.
as i am sure there must have been some other eegit that did this, there must be a trick of the trade for this and/or a handy tool.

help!

Basil · Post by **Basil** » Wed Jan 04, 2006 8:19 pm

Hi, Snap-on do a thread restorer you can use with the head in place, best bet is to make sure that piston is on tdc and give it a good blow out afterwards with an air line, and smear some grease on the tool so that most of the swarf sticks to it.

Basil

Andy Dawe · Post by **Andy Dawe** » Wed Jan 04, 2006 10:42 pm

Most decent motor engineers will be able to fix this for you. By recutting as previously mentioned. You will have to be extra careful in the future when refitting plugs as it will be more prone to cross threading again. If it's bad they can drill, tap the hole and fit a helicoil. I've heard of this being done on steel heads without head removal and the swarf collected using strong magnets. Not sure about the V8 heads.

Let us know how you got on