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I Stripped The Threads.....help!

S

sscam69

Guest
I acutally didn't strip the threads they were in bad shape but I put the finishing touches on it.

Its an aluminum manifold and as I was bolting down the carb the threads gave way. My mechanic suggested that I get studs, which I did and as I was torueing them down one of them gave way. Out of the 4 two are good 1 is almost gone but can hold and well the last one gave way. It was a used manifold and that was the way I bought it.

Where can I buy a thread kit to fix it. I have seen in Chevy Hi-Performance kits available where you drill a bigger hole, thread it and put a steel spring like thing in place that has the same inner diameter of the original screw so that you can reuse it.

sscam69
 

69MyWay

Well-known member
Joined
Jul 3, 2001
Messages
4,364
Location
Auburndale, Florida
Corvette
1969 Killer Shark
Go to NAPA with the carb stud, and let them match up the thread and sell you a good heli coil kit.

No need to over torque these when you get it back together. I would suggest taking the mainfold off, but at least you will need to seal up the runners with some rags and tape, then vacuum it out clean before you pull the tape and rags back out.


The heli coil kit is easy and simple. All you need is a drill. Many times they either come with the drill bit, or at least will tell you what size to buy. You will drill it out. You will then tap the hole with new threads. You will then screw in the heli coil threads that will reduce the hole back down to the original thread size. I would suggest putting some good lock tight on there, but in either even follow the instructions.

You will be able to screw the stud right in there. No need to get too tight on the stud. Just snug it with some good lock tight. Then, you will use a good quality washer/lock washer with the nut and apply light torque when putting the carb back on.

Don't sweat it, it happens to the best of them!
 
S

sscam69

Guest
Thanks

I will stop by on the way home!

sscam69
 
W

wolf_walker

Guest
Oh god the long cold agrivating evenings that come to mind. "It'll just take a second" Then comes the bolt that feels funny, and it's all down hill from there. :(
 

vigman

Motor head!!!!
Joined
Feb 13, 2001
Messages
3,471
Location
Valencia, CA,USA
Corvette
88 Convert ( SOLD ) /1973 coupe 4 speed/1964 Vert!
Well not a bad thing

We all have stripped a bolt or 2 in our time, heck at least you didn't snap it off!

Go Heli Coil

Mike
 
S

sscam69

Guest
Been so busy that I have not had a chance to go buy the part.

I will let you know when I get a chance. I am hoping to do it on friday because I am driving the car but if not for sure Sunday. That day is reserved for "restoring".

sscam69
 
B

Bullitt

Guest
This reminds me of a story my father told me. His brother-in-law had been working on his Chevelle, taking great pride in showing off his handiwork. After replacing some rubber brake lines and front pads, he proceeded to remount the wheel. Someone said, "be careful tightening those lugs up."

"Shut up! I know what I'm doing," was the reply.

All of a sudden the lug wrench gave way and spun a full 360 degree sweep, after the lug was seated down. What was only to take an hour or so, became a day long project on a Sunday. So everytime my father sees me tightening wheel lugs, he says, "those wheel studs are pretty stubborn to replace."

--Bullitt
 
S

sscam69

Guest
Thats helarious LMAO

Reminds me of this weekend. I had to replace the rotors and drums on my cutlass this past weekend. That was suppose to be time for my vette as it needed some TLC to.

Well from 9:30-5:30 it took to get all the parts that I needed and when I thought i was finished i figured out that i forgot to hook up the line for the emergency brake on the right rear tire. There I go tearing it apart again.

Anyways I did what I could on my vette with the daylight that was left. I changed the exhaust gasket, adujsted the tappets cause they keep loosening up (going to replace the nuts) and replace the bolts that hold the carb with studs. Thats when I stripped the threads on the manifold!

sscam69
 
S

sscam69

Guest
I finally installed that heli-coil kit on the manifold. I also got back my digital camera so I was able to take pics for those who don't know what it is.

The kit cost me about $40 and did not come with a drill bit. It came with an installation tool, 10 heli coils, and the tap (used to thread the hole)

Here are the pics. The fist one is of the manifold w/o the carb. You can see the missing stud on the bottom right.

 
S

sscam69

Guest
I stuffed rags down the manifold and put tape over it to prevent debri from entering the engine. I also had a vacuum running as I was drilling.
 
S

sscam69

Guest
Here is one of the drilled out hole. I forgot how easy it was to drill through aluminum. The drill just had an on and off, there was no way to gradually apply the speed. As soon as I clicked it tore right through.

Fortunately I had the drill aligned up rignt and was ready for it.
I would suggest buying something that can help you align the drill to the hole.
 
S

sscam69

Guest
Here I am trying to align the tap with the hole
 
S

sscam69

Guest
Here is the top view.

I got a rachet and tried different sockets and found one that fit snug at the end of the tap. I slowly turned the tap until I felt it catch a little and checked the alignment. I had to do it 3 times before I got it rignt on.

I slowly turned the ratched until I felt it was digging in pretty well. I made one full turn (360 deg) with the rachet and then a half counter turn (180 deg in reverse direction). This works in those threads. Then turn until you feel it tighten again and follow the same procedure until you work in the amount of thread that you need.

OH remember to use oil to lubricate the tap. It will reduce the friction and make it easier for you. Since I was tapping aluminum it was pretty easy to turn. But if you are tapping steel its going to be a little more difficult

I had to use the socket and rachet because I didn't have the right tool that went on the end.
 
S

sscam69

Guest
I am miissing the pic of the heli-coil installed, sorry. But its pretty much cake after that. I hope this helps for future reference.


Frank
 

Tom Bryant

Well-known member
Administrator
Joined
Nov 9, 2000
Messages
7,304
Location
Edgerton, Ohio, United States
Corvette
1959 black 270hp (9/2/69) 1981 Beige L81(10/20/80)
Nice how-to SS. That would make a good article for the Knowledgebase section of the site. Excellent pictures too. That one pic looked like the hole went clear through into the runner. If it did make sure you use some thread sealer on the stud to avoid a vacuum leak.

I'm also curious about your engine. How is it equiped and how do you get along with that single plane intake on the street?

Tom
 
S

sscam69

Guest
Easy I just push the gas Tom LOL j/k

It does not have a radical cam on it so she is still pretty streetable. She pulls about 12inHg when tuned right. I think I can get more but I could not tune it because there was a vacuum leak from that missing stud. I have got a true dual exhaust setup on her, some stamped roller rockers and a 670 holley avenger carb. Thats about it. I think the mechanic put a truck cam because thats what the car sounds like at WOT as your pulling away. I asked for high performance, thats not exactly what I had in mind.

I put an alan wrench through the hole to mark the depth and then marked that on the drill. I just watched the drill and stopped just short of hitting the mark. There was still more than enough thread to use the stud so I was not worried about it.

The pics were kinda dark because it was in late in the afternoon and right now it was raining cats and dogs, litteraly! As soon as I installed the stud it started to rain. I just placed the carb on top of the manifold, shut the hood and tried to get all my stuff, tools, vacuum cleaner, drill and such, before they got soaked.

I get some pics of the heli-coil installed with a few other details if you are going to put it in the knowledge base.:cool
 

Tom Bryant

Well-known member
Administrator
Joined
Nov 9, 2000
Messages
7,304
Location
Edgerton, Ohio, United States
Corvette
1959 black 270hp (9/2/69) 1981 Beige L81(10/20/80)
Sounds good. If you can get the pic of the heli coil I'll put it together and get it in the knowledgebase.

I have an Offenhauser 360 single plane with carb heat passages I'm going to use on the '69 C 10. The manifold is cast for a GM divorced choke therm and I have a '66 Holley off of a 327/300 hp to rebuild and install. I figure it should start and warm up just like a '66 Chevy did when new; I hope. It seems to me that Offenhauser must have intended this manifold for street use or else they wouldn't have put in the choke and heat riser passages.

Tom
 

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