I started to remove my muffler and heat exchange (left side) due to a noisey exhaust leak. Come to find out that the nuts were so tight that the studs came with the nuts - right off!

I have one nut that is almost completely stripped that I can't get to - to take off. I'm thinking I might have to cut the SS heat exchanger to get to this unless someone has a better idea. Okay back to the real problem.

I've done some research, but still need some help/advice. I've read up on past threads that recommend a 8mm helicoil, tap, and insertion tool, and JB weld. Not forgetting the drill bit that is recommended by the 8mm helicoil package.

First - some of my studs unscred themselves off - should i just JB weld and screw back on?

2nd - can't I just re-tap the existing hole, buy 8mm studs and JB weld?

3rd - is it just best to use the 8mm helicoil kit?

4th - do I have to drop the engine to do this? (I hope not - I'm a rookie)

thanks for all the input and help.

Dooohhhh!!!
I just did the same last nite. I used a 1/4" drive ratchet, long extension, and short 12mm 1/4" drive socket. Tight fit on some locations but worked well.
Four of the 8 studs unscrewed with the nut.
As for your question, I don't know for sure, but it would seem that the helicoil kit would be the strongest method. Although I wouldn't want to try it with the engine in the car - unless you turn the car over first...
JB weld is good stuff - but I don't know about JB weld used on hi-temp applications.

Funny I was also pulling part of the exhaust off my head and had about half of the studs come out to the head. That this was normal, happened on my 74 VW bus as well.

How are you going to approache the stud/nut problem? I still have one that I can get to, but it's a bit stripped - do you have any recommendations on how to approach this one f"ing nut?

thanks,

tapping sucks and sometimes doesn't hold the best

i'd helicoil...


if they came out, use new studs and nuts.

dropping the engine makes access easier, but it's totally doable with it in the car. just be prepared for little aluminum shavings falling down in your face (do wear saftey goggles)


also, if you can't get to some of the nuts with a socket, try using an open wrench "straight down" on them. put a screwdriver through the closed end of the wrench and twist. only way i could get to one of mine....

n

for the one stripped nut, a dremel should be able to cut it off.....

yes, the threads can be repaired while the motor is in the car, it will not be easy and you have a great chance of screwing something up..

what you could do is start by drilling the hole out with a smaller drill size than what is recommened for the 8mm helicoil, then work your way up to the correct size...do not go any deeper than what is already done.

JB weld?? don't know about that at all, not too sure survives at those temperatures.

got good safety glasses or better yet, goggles

What is the difference between helicoil and tapping?

helicoil info

click the above link and start reading

A tap is a tool to cut threads in existing metal. The hole that the tap will thread has to be the correct size to allow enough threads to be cut into the metal for proper retention.

A tap will not work when the existing threads have pulled out of the metal. The hole is now bigger than the tap size.

Enter the heli-coil.

An invention of Chrysler in the 60s for the aluminum block Hemi, it is a coil of stainless steel wire cut to the proper shape for threads. First the existing hole is redrilled to the correct size for the heli-coil tap, then threaded with the supplied tap. After that, an installer tool is used to insert the heli-coil into the threaded hole. This reduces the thread size of the hole back to the original size, in this case 8mm.

now, whats a 'time cert'

call me lazy...much easier to click a link and read it than type it up.....

besides, pictures go a long way to help

don't people know how to f'n use google and try to learn something????

A time cert is very similar to a heli-coil, but it is a solid insert, rather than a coil of wire. It will allow you to use a different thread pitch on the tap that is inserted into the base metal vs the thread pitch for the internal threads on the time cert.

very cool.. so whats better?

my cas has both DAPO helicoiled drain plug and one of my heads intake studs has a time cert...

I know, I know - I'm mechanically challenged - what keeps the heli-coil tap from falling out?????

Depends on the application and location. From experience, I would not use a time-cert on an exhaust stud. The metal between the stud hole and the combustion chamber is kinda thin, and the time-cert requires a lot larger hole to be drilled and tapped than a heli-coil does. I had a hole blown from the combustion chamber into the hole for the exhaust stud on Betty's 1.8. Not a fun repair when it happens on a Monday, and you are supposed to drive that same car to Oklahoma for the MUSR on Thursday.

I made it though..........

Just my .02..... But Jake may disagree.

I have been using an alternate product to the JB weld for several years now, and excellant results. ( Better than what JB in my opinion)

Now this is going to sound real stupid But I cannot remember the name of it, so I will describe it:

Comes in a small tube, stiff paste consistency, Two parts, the activator is a dark grey and it is extruded into the center of the hardening paste.

What I have thus far used it on: When rebuilding one Weber, I broke of a float tower. I used this product to cement it back together, and built up a small margin around the cracked perimiter, and Voila--one year of driving, and still intact!!!

The other in a hihg heat area, one of my ex. studs reamed the tapped hole into oblivion, in a pinch, gooped up the hole with his stuff, and then plopped the stud into the hole, one hour later, bolted it back together, just checked it before writing this to keep honest, and all is there with no signs of leakage..

Think I paid 4 bucks for it---and it has saved my ASS.......TWICE

What keeps the time cert/helicoil from falling out?

The tension of the coil in combination with the squeeze effect of the stud and the walls of a properly spaced hole.

BTW....Sears makes a reverse tap nut puller....I would try that first if the space is to tight to get a dremel in....

red loctite