Head Stud Barrel Nut Removal Procedure?

SCrescue · SCrescue's Garage

I've got a barrel nut that's threaded too far down on a lower stud to allow an allen wrench to grip enough of the nut for removal. Wayne's "How to rebuild and modify" book illustrates a good picture of the condition (2-21 on page 28), and alludes to how difficult it can be to remove if tight, but doesn't say how to remove it. Who can tell me what the preferred method is for removing the nut?
My guess is to carefully drill a pilot hole down the center of the stud and then step drill to the diameter of the stud (at least deep enough to allow an allen wrench to grab the nut), without removing any of the nut material and destroying the internal hex. Is this a realistic prospect? Is there a better method anyone can advise me of? This is a '79 3.0 motor that doesn't appear to have ever been disassembled before, so I expect the stud to be dilavar. How drillable is dilavar? Thx

Mike

dfink · 01-14-2007, 07:01 PM

I used a dremel on a flex shaft with a small carbide ball and cut grooves down the existing angles of the allen to create a make shift torx. Then ground the body (not the bit) of a torx bit down so that it would fit in the recess that the head is in. The nuts are suprisingly soft. You could also probably use the same bit to cut a slot in the nut and use a really large screw driver. If doing this make some accomodation for the metal dust from cutting. If not pulling the cylinders leave the spark plugs in and then use a magnet to remove the particles.

Determined · Determined's Garage

Wow, its sounds like you may be missing the washer below it or even possibly the wrong one in there. Be sure to use a flat ended allen wrench and not a ball type. The flat ended wrenches provide a better grip when compared to the ball ended types. I soaked all mine over night with PB Blaster to penetrate a bit before removal. Is it possible that the barrel nut has been rounded off? What ever you do be careful not to damage anything else. You may want to buy a deep socket style nut remover, I believe Sears may sell some. Good luck, Alex.

im4duke · 01-16-2007, 05:54 AM

SCrescue,

I followed the exact process you described for 2 studs on my engine recently. The only difference is that I used a large drill bit to start, right about equal to the diameter of the stud. The barrel nut kept the larger bit centered, whereas I figured a pilot would be hard to center on the stud. I only drilled down a little bit as i wanted some stud left to ease the removal process of it later. I then tapped my allen socket down into the nut and it came out easily. Oh, I had also PB blasted for about a week...

Good luck.

SCrescue · SCrescue's Garage

Thanks im4duke, I think that's my best bet to remove the nut. It looks to be the only one I'll have to do this on, the rest of them look like they have enough hex showing to grab onto. I've been spraying all of them with PB Blaster every chance I get, so I'm sure its penetrated by now. Is the dilavar relatively easy to drill? What type of drill bit did you use?

I'm still confused as to how the nut can get threaded that far onto the stud in this way. It defies logic. The only thing that makes any sense is if the stud pulled, or broke, and vibration eventually caused the nut to thread itself further onto the nut, but then the entire stud and nut would be loose and I should be able to pull it out. That's not the case, its on tight and I can't imagine how anyone could have torqued it that far onto the stud. The stud is just about flush with the top of the nut!

Anyway, thanks to all for replying. I'll tackle it this coming weekend and let you know how it goes.

Mike

Walt Fricke · 01-16-2007, 06:57 PM

Mike

Sounds like someone did not put the stud in deep enough. Then tightened the barrel nut until the hex (perhaps a nice sharp edged one) slipped. And at that point was unable to remove it to slip another washer on. If so, you may be able to remove even that nut.

1) after removing the cam carrier, take off the other three nuts. This will remove some of the tension on the stud. You'll see the head move up a bit on the other side.

2) with a small chisel and a punch, distort the edges of the barrel's hex so the tip of your Allen will have just that much more bite. The nut is toast, but so what. Keep building up metal toward the inside. Then hammer the Allen in. At that point you may not need much torque to start it moving.

Walt Fricke

im4duke · 01-16-2007, 08:07 PM

SCrescue, I just used a generic, off-the-shelf, low-quality drill bit. It was very easy to drill. Like you, I thought about what to do for a while, approximately 2 weeks in my case, then when I figured out that this would be quite simple, it took all of 1 minute per barrel nut from drilling to removal.

SCrescue · SCrescue's Garage

Walt,
The thing that really baffles me is that I don't think this motor has ever been disassembled before, so that would mean it came that way from the factory. I can't imagine a Porsche factory mechanic making such a rookie mistake and not correcting it.

I've already removed the cam tower, but I'm still fighting with the HE hardware. I've tried the PB Blaster and heat combo, but none of the nuts will budge. The hardware is so rusty (both sides) that I'm contemplating cutting all of the nuts off with the dremel tool. And if that gets too frustrating, I'm just going to cut the HEs off with the die grinder cutoff wheel and let the machine shop remove the flanges.

After I get the HE off, I may try one more time to get the nut off without drilling, but drilling it off still seems like the quickest & easiest way to do this...1 minute per, ooh baby, that sounds about right to me....I'm gonna jump on it tomorrow.

Thanks again for all the suggestions.

Mike

cstreit · cstreit's Garage

I used a drill press to create a depression in a 10mm allen socket center to do this. It allows the allen bit to get must a bit further down into the nut. It weakens the socket so you can't use a lot fo torque, but the ones threaded too deep are not usually torque properly anyway...

OldTee · 01-19-2007, 09:22 AM

Just had this situation on my car. Two barrel nuts would not turn with the Hex. Age had wallowed out the inside of the nut. We took a tourch to the nut, red hot while hitting it with an air chisle CCW while using the hex to help it along. After the air chisle turned the nut about 1 turn the hex began to bite and off it came. You can't beat heat here.

im4duke · 01-19-2007, 09:52 AM

I took one of the barrel nuts that came off without a problem, selected the largest drill bit that would pass through it and drilled the top of the stud a few mm's. Tapped my hex socket into the nut and off it came. Did this on 3 in a row. As long as you want to replace the studs, this is the way to go.

davidppp · 01-19-2007, 11:57 AM

Hello there.

Grind through the old stud, between the barrel fins.

You do not want it anyway.

Kind regards
david

SP2 · 01-19-2007, 06:18 PM

Whoa, try to do it first without damaging the stud. Why? Because it is a pain to remove the stud. I removed the stud with Christian's device, so I know first hand. (I am also a rookie, so my first barrel nut removal, I snapped the stud.

What I learned (one stud too late) is that you have to heat the barrel nut red hot, then immediately turn the nut. While it is still hot, it turns off with very little force.

So I am pretty sure that you could grab a hold of the nut with some pre-set vice grips and turn it off. I would have a buddy with a MAPP torch that you can buy from Home Depot, etc., and have him heat the nut until the nut is completely red hot. At first I was impatient and started to turn the nut while only the top half was red. Then with you standing by, immediately grip the nut with your vice grips and turn it off. I can't tell you how amazed I was at how little force it takes. You might get the mini-vice grips so it will fit under there better.

You might dremel the edges of the barrell on two sides flat if the vice grip slips.

Even if you think the existing stud is too tall, you can refasten your heat exchanger with a plain old 13 mm copper nut. That is what Steve Weiner told me he does. He never uses barrell nuts because he said none of them are made of copper. When I bought my SSI's from him he sent me 12 copper nuts for installation. (I know I could have bought from Pelican, but Steve is so nice to me over the phone with all my questions that I wanted to send him the business. Pelican has more than 3k of my business already, so no disrespect on my part.)

Good luck! Save that stud!

SCrescue · SCrescue's Garage

Well, I'm having no luck trying to drill down into the stud. None of my drill bits seem to be able to penetrate into the dilavar stud, not even cobalt bits. I tried cutting into the nut at six points to allow an oversized torx socket to grab the nut (dfink's tip), but I burned up two dremel metal cutting bits in the process and the torx bit still won't fit. I think I'm ready to try David's method of cutting the stud between the fins, but I'll have to go through the fins where the washer is visible, so that I don't leave part of the nut clinging to the stud.

Mike

davidppp · 01-20-2007, 01:18 PM

Hello there.

Ise a biggish daimaeter slitting disc and take time.

No worry if you also damage the next stud..it will be junked too..

I have only done this twice..most times a well ground hex will catch..

Kind regards
David

'78 SC · '78 SC's Garage

Mike,

Before you try cutting the stud, take a look at John Walker's technique here.

SP2 · 01-20-2007, 07:03 PM

Uhh....with regards to my earlier post, I thought you were talkin about the barrell nut on the exhaust head stud. So, uhh... nevermind.

im4duke · 01-20-2007, 07:50 PM

Quote:

Originally posted by SP2
Uhh....with regards to my earlier post, I thought you were talkin about the barrell nut on the exhaust head stud. So, uhh... nevermind.

Same here.

OldTee · 01-21-2007, 04:56 AM

ditto.

dfink · 12:18 PM

I was talking about the head nut. What kind of bit did you use was a little round ball with teeth. If you want I could try and dig out the bit that I used and also the send the torx bit. I ground off the outside of the socket part of the torx so it would fit in the recess of the head. Let me know and I will take a look. I was suprised at how easy they ground off.