exhaust manifold studs stripped

[spammy123]

well i thought i had a leak issue somewhere int he exhaust and found that some of the bolts were loose on the 4-1 part of the exhaust manifold. i started tightening them and then they just fell out, i bought some new ones because they were put in there with some real hard sealer of some sort and had no more thread. the question is, how do i get it in there. i thread the smaller sided of the thread in there by hand to just start and get it threaded but then wen i put the nut on to tighten it, it just unthreads itself.

 

[romeen]

The best way to fix this would be to use Helicoils. You will need the M8 x 1.25 kit.

 

[spammy123]

is tapping it real hard? i dont wanna mess it up even more.

 

[romeen]

It's really not hard. Best advice is take your time when doing this. Of course you need to drill the hole first. I forget the size of the drill bit needed (possibly 27/62" but often times the drill bit comes with the kit and if not the kit instructions will tell you what size bit is needed).

The main problem is not having enough space between head and radiator/fans to get a drill in there at a 90* angle to the head. You either have to remove the fans and possibly the radiator or you can get an attachment for your drill which has a 90* bend in it (only about $10 at harbor freight). The latter is what I did.

Also, be careful not to drill too deep into the head! Use the stud as a reference and put masking tape on the drill bit so you know when to stop. Take into account the thickness of the manifold flange when using the stud to gauge depth.

 

[TSiAWD666]

You won't need to drill the holes in this case. You can start tapping immediately. The holes exist already and are the right size for the m8x1.25 tap provided with for the inserts.

 

[romeen]

The i.d. of the inserts is 8mm but the o.d. is obviously bigger, therefore drill the existing hole bigger is required. The drill bit needed is actually 21/64. Some kits include the drill bit, some don't. But all the ones I have seen do include the appropriate size tap.

 

[TSiAWD666]

No, you do not need a drill bit to repair these holes. You can start tapping without cleaning up these threads. I've done eight of these (manifold stud re-taps that is) across two cars this way and it works perfectly.