i cross threaded the bolt when screwing my valve cover back on my 99 cherokee 4.7. i'm using a heli coil so the valve cover stud can screw back in.
i know the stud is 10 mm, but don't know the pitch of the stud and the autoparts store says they have to know the pitch to give me right size heli coil. could anyone help me, cause i can't find pitch anywhere online..
thanks

 

It's probably an M10 X 1.5

Conversion factor: 1mm = .03937". That makes the distance between threads about 1/16"

 

Thanks for helping me. I've never used one before and never see them at the autoparts places. I really had no idea that I had to know all that when buying one...
Thanks again!

 

Do you know the procedures for installation? The hole must be drilled out oversized and a Helicoil tap run into it to make a special size thread for the insert. Then the insert must be screwed in with an insertion tool making sure it's the right depth, the drive tang broken off, the drive tang removed from the hole by being blown out with air pressure, then the bolt installed. I've installed many in my life as a toolmaker. Done properly, the resulting thread is stronger than the original.

The insert is basically a diamond shaped stainless steel spring who's internal size is the same as the thread you are trying to repair. The drive tang on the bottom is notched so a sharp blow with a punch will break it off so the bolt will pass completely thru without bottoming out. I've installed them as small as 4-40 UNC and as large as 3/4-10 UNC.

 

Having not done it before. My advice would be take it to a machine shop and have a pro do it. It's only 1 so it should be pretty cheap. Thats just me though. I would want to get this done right the first time and get on with it.

 

Blueseasons has a good point. If it isn't tapped straight, you may have trouble getting the bolt in or the stud not fitting thru the cover hole.

 

Ok, thank u both for letting me know. I'll hold off
When I screw the valve cover bolt in it'll just keep turning. I'll then go to pull it out cause I'm thinking it's stripped or I cross threaded it. When I pull it out I can feel it catching all of the threads in the hole and it don't just come out. Have to use little strength still.
So my plan is to get a valve cover stud from my buddy's junkyard this weekend and screw that stud in and see if it'll work. I'm pretty sure the other studs threads are messed up from that and maybe a new stud is all I need.
It's worth a shot, especially since it's free..

 

Definitely holding off on a helicoil...I'll have a shop do it if I end up having to go that route. If I mess it up, this could end up costing me money I don't have!