Heli-coil exhaust manifold stud.

[DiamondStarAwd]

I need to heli-coil a stud that is stripped and I have already pulled out, I searched the site and could not find any right way to do it. If anyone can explain that would be great.

 

[Eclipsethis90]

go buy the corresponding Helicoil kit you need for the original size of bolt. You will need :

-Tap t-handle (reccommended) or even a cresent wrench
-small hammer
-oil (any lubricant, tapping fluid is best but even motor oil is better than nothing)
-helicoil kit for bolt (Should include: helicoils, insert tool, and tap)
-Pin punch that can fit in the helicoil
-Drill and drill bits

On each kit it will specify a size to be drilled I recommend going out and buying that exact size if you do not have it. You can get away with a few thousands of an inch bigger (ie: .250 and .256), but do not go smaller or you risk breaking the tap. Drill out hole at the same angle you want the fastener to come out of the housing and lube up your helicoil tap. Use the tap t-handle ( or small cresent wrench) and tap the housing STRAIGHT THE WHOLE WAY. If the tap is tilted even a little it will bind and break or make the new fastener tilt with it. Use an airgun or even Q-tips to clean the hole out. Put helicoil on insertion tool and thread it in the new threads till it sits flush with the hole, then go a half turn further. Back the insertion tool out and use the punch and hammer to knock the little "Tang" or "dog leg" off the the bottom of the helicoil that is in the hole. You can remove the little piece that falls off or leave it, your choice. I am a machinist in the USMC and we do about 10 to 15 helicoil jobs a week on VERY expensive aircraft parts, if you need any advice please PM me for guidance.

 

[Eclipsethis90]

Before i forget, take your fans off to make more room for the drill so you can line it up straight.

 

[bling5tatus]

Hey, I pulled some threads out in my intake manifold and need to helicoil it. I already have the kit and the corresponding drill bit, the thing is, I'm afraid of messing the hole up, I started to drill it, but was unsure of how level I was drilling. I do not want the hole to be crooked, I can handle the tapping part, but it's the drilling part that I am afraid of. Is there any good way to make sure the hole is perfectly straight without some kind of drill press? Or do you have any tips on a better way to do this?

Sorry, I'm not trying to jack this thread, but I figured that heli coil advice was being offered.... so yeah, please don't mind me.

 

[blazebolt]

When I helicoiled ALL of my exhaust manifold studs (misread the manual and over torqued), I did not use an electric drill. I simply put the drill bit into the tap holder (I don't know what it's called right now, but it's the handle that you put the tap in). So instead of putting the tap, but the drill bit and drill into the head by hand. The head is soft enough and you can go really slow and as a result you pretty much go straight as it is harder not to.

 

[bling5tatus]

^^really, that is a good idea, I will have to try that, the only problem is, the drill bit I have is round on the part that goes into the drill so attaching it to the tapping tool probably isn't an option. I just don't want to fubar anything.... I got it just now.... I will grind the drill bit a little so that I can attach a "handle" to it. Alright good deal, thank you for the advice.

 

[ZmanIV]

you don't have to grind the drill bit just tighten up the locking collar on the tap handle.
Tineserts are a better option for redoing the mounts for the exhaust studs.
These are like small threaded setscrews with tines that project from the front. drill and tap out the hole like a helicoil, insert tinesert untill flush with the outside surface, tap tines in with a hammer and the insert is now embedded into the soft alloy.

 

[95tsiawd6blt]

what size drill bit should be used for drilling an exhaust manifold stud?

 

[95tsiawd6blt]

? anyone

 

[romeen]

what size drill bit should be used for drilling an exhaust manifold stud?

Are you talking about using a helicoil? You will use a 21/64" drill bit in preparation for the M8x1.25 tap. Some kits come with the drill bit needed and if not it will tell you what size is needed.

 

[02HtownSubie]

Are you talking about using a helicoil? You will use a 21/64" drill bit in preparation for the M8x1.25 tap. Some kits come with the drill bit needed and if not it will tell you what size is needed.

You are absolutely correct, the drill bit for helicoil kit M8x1.25 is 21/64 drill bit. I did four stud holes on my 1g head today and it work out great however the first hole I didn't tap deep enough for the coil to completely insert into the stud hole and I have to cut it off/re do. There should be the instruction come with the kit #5546-8.

 

[blcknspo0ln]

http://www.dsmtuners.com/forums/articles-miscellaneous/267280-how-use-helicoil.html Wow, I never even noticed I didn't put the sizes in there. Thanks romeen + o2