Blew out exhaust studs

Well it just never ends.. Just when things are going good and the car is running great Boom!!! I knew that one of the studs connecting my headers was questionable but I planned to fix it soon. It blew today on the way home and took the second stud with it. I drove it gingerly 2 miles to get it home. Do you guys think that short distance could have messed anything else up.. I now have to remove the driver side header and drill out the two studs on the head closest to the rear of the car. What a pain in the ass!!! If I burned a valve or worse at least I'll finally have a reason to rip out the engine and make some cool mods...
Thanks,
Pete

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www.geocities.com/pcafaro2000/carrera30.html

I have no answer for you. I'm here to send condolences and so forth.

For me, I've heard all kinds of noise out of that engine. Thought was tensioners, but now I think the alternator or the fan is making some kind of squeaking. Not to mention, after the rain we've had, my idle is totally jacked.
After I drive for a while it randomly jumps up to 2k when I stop--something's getting stuck. Think it's the air flow meter.
Then I compensate by lowering the idle, and it randomly stalls. Driving me nuts.
Air flow meter comes apart this weekend since new one is 595$. Forget that.

Anyway, sorry about your mess BTW.



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Kurt B
1984 911 Carrera Cabriolet
75 914 1.8

Thanks Kurt..
Hopefully there is no further damage.. I'm currently taking a break.. Having a hell of a time with the MIG welder.. Melted that damn nut on the stud real good but it keeps breaking loose. About to attack with a torch.. Hopefully the fire extinguisher will not be needed..
Pete

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www.geocities.com/pcafaro2000/carrera30.html

Kurt!
Hunt around. I paid around $300 for one new about 2 yrs ago.

-d

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Dave
1972 911T (E motor) RSR replica project
http://members.nbci.com/dtwinters/garage/

I am doubtful that a valve has been warped. Unless the gap between the head and the header is bigger than I thought. I suspect the header and head kept the exhaust valve warm enough during cool down.

Snap-On makes a very nice set of screw extractors if they're broke off flush, and the set (8 or 10 I think) costs less than $30. It's much better than any other 'easy-out' tool I've used.

And finally, high idle problems can sometimes be caused by distributor advance mechanisms that are sticking. If you can reduce the idle by letting the clutch out in gear to slow the engine - if this reduces the idle, your advance mechanism is probably sticking.

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'83 SC

This Sucks!!!
One stud is now broken flush to the head. The other is horribly disfigured from welding nuts to it and then having them break off again. If the threads in the head end up damaged is there some kind of insert that can be purchased to correct the situation?? I'm done for the night and any advice or list of required materials to fix the situation would be greatly appreciated. Looks like I'm off to the hardware stores tomorrow...
Thanks,
Pete

I admit that as a machinist, every now and then I put a hole (sometimes tapped) in the wrong place. I just drilled it bigger, Tapped it, screwed in a threaded rod, cut it, peaned it to expand it in the hole to make it hold, redriiled it in the correct place and size. Quite often in soft material we would put in harder threaded inserts or "heli-coils". A good machine shop has experience to fix anything in metal and then some.

George
83 911SC Cab/Euro

Pete,

There are Time-Serts for 8 mm studs, though you don't hear much about them. An interesting thing about exhaust studs vs head stud repairs is that we hear about the head studs more, but the exhaust studs are the much more likely occurence! For any vintage, any displacement 911 that you might own ... if you do exhaust work, you are very likely to damage heads in the process!

And the curious thing about Time-Serts is that we are the benefactors of a healthy VW air-cooled engine 'industry' in this country! Instructions for the installation kits have pictures of the VW Type 1 engine block, and the title of the instruction sheets specifically references VW engine repair kit!

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Warren Hall
1973 911S Targa

The Time Serts Warren mentions are a great repair option. They have more of a bite due to their design than Heli-coils. I too, had problems with the header (exhaust) studs on my 72' 2.4. I have installed 2 Time Serts and those studs seem as good as new.

The kits are about $60 for all the tools and 4 (I think) 8mm inserts.
Jack McAllister

Thanks for all the info.. If I do indeed need the inserts where would be the best place to look for them? Any auto part store or do I need to find a specialty shop??
Thanks again,
Pete

Does Pete need to remove the head? I've heard you NEVER drill studs out of these heads without removing them first. but I've drilled broken fasteners out of aluminum before and it can be done. Here's my
method:

First you need a 500 gallon tank of patience. I also recommend the Snap-On set I mentioned above (REX10A), an actual bargain on the Snap-On truck at under $30. The smallest one is used with a 1/8" drill bit, so go get a reverse (works counter clockwise) 1/8" bit and also another reverse one a little smaller.

Spray real penetrating oil on it for days. I use Maltby's. Using a punch or awl, punch a dimple in the center of the fastener. Tap lightly as you do this. A good, solid dimple. If the drill bit slips, you will damage the head. Believe me on the patience thing.

Using the smallest bit, drill a hole in the center of the fastener. Drill it exactly straight and don't wiggle the drill. Remember, if the bit slips, it will chew up the aluminum head. If you get tired or angry, STOP.

Sometimes the fastener will back out as you're drilling it with the reverse bit. If you need to, follow up with the larger bit. Here's another excellent chance for it to just back out. The larger bit will try to 'catch' in the hole, which can break it loose, but be careful. Dodn't wiggle the drill. Drill absolutely straight.

If you get the 1/8" hole drilled without the fastener backing out, then use the Snap-On tool. It works well. I believe this can be done, but I'm prepared for dissenting opinions.

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'83 SC

Oh please do not make me remove the head!! And to set the record straight I've already started to drill. Got a nice hole started for a tap/dye kit if it will work. Look what you guys made me do to the clean garage.. Please do not let it me in vain!!
Pete

Hey Rarly...yeah, it does go down when you decelerate to within it's limit. Then it bounces up to 800 like it should (kinda low now, was 950 or so).
It also goes back down if you pop the gas a bit, snap the pedal I mean. I cleaned the air flow meter and that seemed to help, but how do I check the timing advance on this thing? It's totally self contained in that distributor (which is pretty mechanical inside--not sure what's going on there).


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Kurt B
1984 911 Carrera Cabriolet
75 914 1.8

Ok,
After a million drill bits, 1 oxy-acetalyn torch 2 heli-coils and various air tools, the broken studs are out and the good ones are in. This was my first experience with this kind of thing.. It sucked bad!!!!
All that's left to do is button her up and listen for exhaust leaks...
Thanks again,
Pete

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77'Carrera3.0 www.geocities.com/pcafaro2000/carrera30.html

Are you serious, you did that by YOURSELF? I may have to do that someday, and I can't bear the thought of attempting it myself.

I would love to hear details, and mega congrats on the work!

I was thinking about posting this for several reasons.. One, my brother and I did it. Two, there are lots of things than can and probably will go wrong should this be attempted. Three, the sight of the oxy-acetylene torch cutting away under your car is enough to give you a heart attack (if you don't blow yourself up first.) After realizing that those easy out extractors are crap and will probably never work when you really need them to, I decided to drill them out and try the heli-coil idea. One stud drilled out fairly easily. Started with a real small bit and worked up to the 21/64 that's required for the 8.3 mm coil. The other stud wasn't broken off flush so I tried a million times to tack weld a nut to it. No dice!!! Had to cut it flush.. Started at it with a small bit and a little too much confidence. "That last one was easy, who needs to take their time.." Not me!! Ooopps!! There goes most of the drill bit!! How the hell are you gonna drill out a stud with a drill bit in there?? Your not!! Here's where the fun began. All the guys are over drinking beer watching this catastrophe and laughing at me.. My cousin grabs the torch, turns on the tanks , fires it up and says "let me at it!!" Wait a minute he may have something there... After finding the right tip, one with the most narrow and directed flame a couple of attempts were made at killing the bastard stud with new found drill bit friend... I'm not sure how much good it did but I was able to chisel the bit out right after the flamefest and the drilling continued. Amazingly enough the stud drilled out straight, the heli-coil was inserted, followed by the stud and all is well so far. One thing that's worth mentioning is you don't have to drill out the whole stud to make this work. The replacement studs that I bought have threads at both ends and a smooth area in the middle. I took a piece of tape and wrapped it around the drill bit at exactly the depth of the threads on the new studs so I knew when I could quit and installed the studs. The headers bolted right up with no discernable leaks. This was far from a text book repair, but would have been fairly easy had it not been for the drill bit!! Thank God I didn't need the fire extinguisher!!!!
Good luck if this happens to you!!
Pete

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77'Carrera3.0 www.geocities.com/pcafaro2000/carrera30.html