Ducati engine - stuck headstud WTF

jwasbury · 01-31-2009, 01:03 PM

This mother f-er is being a serious beotch. Vertical cylinder on a 1995 900cc engine. Ducatis of the mid nineties were known for headstud issues. The horizontal cylinder popped a stud at the track and the broken one had to be drilled out then case was heli-coiled. I am changing out the vertical cylinder studs as preventive maintenance. Got 3 of 4 out and this last one is kicking my ass. I've broken it loose and turned it several rotations but then it reaches a point where is won't come any further. I've hit it from the top with a hammer to try to break it free, and also applied heat with a propane torch to the case area surrounding the stud. Just hit it with Kroil and now I'm going to walk the dogs, get some beer and see if that improves the situation (the beer, especially).

Suggestions for what else I should try...don't want this one to break...Major PITA.

Aurel · Aurel's Garage

Heat again, use an extension on your wrench, have an assistant heat while you turn it.

fastfredracing · 01-31-2009, 01:28 PM

Probably a little more heat than a propane torch. That looks like a pretty meaty section of aluminum around the stud, and aluminum is a great heat sink. At least a map gas torch. If you can get your hands an oxy-acetalyne that would be better, just be careful with the latter as you can melt the case with it. If you can double nut, and then try to gently use an impact gun after it is hot, may help also. Good luck!!!

ruf-porsche · ruf-porsche's Garage

Don't use an impact, you never feel when the stud is about to snap until it is too late. Use more heat.

Eric Coffey · 01-31-2009, 01:50 PM

What Fred said regarding more heat/better torch. It would also be much easier with 2 people.

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fastfredracing · 01-31-2009, 02:13 PM

Also, when you apply the heat, try to heat the case from the inside the spigot, . When I use an oxy torch, I will also use an infrafred thermometer to see if I have the case hot enough, or too hot. I think Porsche says to heat to something like 220 deg., cant remember for sure, but ckose to that . You can puddle aluminum with a big torch so tread carefully.

jwasbury · 01-31-2009, 04:14 PM

MOTHERFFFFFFFFFFFkRRRRRR

Went to the home creepshow and picked up MAPP gas torch. Mucho better at heating the case. It was pretty fking hot because water pooled around the area was boiling. I was able to move the stud out some more...first 3 or four threads are now showing, but damn it that thing is fighting me hard. Kept working at it for an hour or so, but my hands are now swollen to hell and hurting badly. The freaking double nut keeps walking on me, so I torqued it to 80ftlbs according to me big torque wrench, and it still walks before the stud unscrews. Gawd I hate this crap.

Aurel · Aurel's Garage

You could weld the nut on the stud to prevent it from walking.

jwasbury · 01-31-2009, 04:34 PM

Quote:

Originally Posted by Aurel

You could weld the nut on the stud to prevent it from walking.

If I had a welder. Nope, not buying one for this job. I'll drag this POS to the curb before I spend another $ on it. I'm actually thinking that the headstud is like excalibur in the stone. Whoever gets it out is the King, and is the true master of this machine.

BGCarrera32 · 01-31-2009, 04:47 PM

Seriously...remove the double nuts, get a grinder and buzz a couple nice flats on the threaded end and throw a monster crescent wrench on it. Have an assistant heat the case from inside the spigot (as others have said). Hit it tonight with PB Blaster...go after it again tomorrow. This is what I did to get out my Dilivar studs from my 3.2 case and I had all 12 lowers out in a hour with no broken studs. Sometimes turning the stud back in a half turn and shooting it with PB again helps too.

And wear leather gloves to protect the grabbers.

BGCarrera32 · 01-31-2009, 04:50 PM

You *will* conquer that turd.

Shaun @ Tru6 · 01-31-2009, 04:55 PM

it sounds like you have a piece of debris walking through the threads much like a little chunk of carbon can get inside of a spark plug thread and you think you are tearing your head apart just pulling out a plug.

I think heat heat and heat are the only things that will help.

TerryH · TerryH's Garage

Hopefully the thread isn't galled and bringing aluminum with it. Hate to say it, but I can't think of any other reason for it not loosening up. Might need another heli-coil before you're done.

jwasbury · 01-31-2009, 05:09 PM

I've stepped away from it for the night...before I smash something important with my BFH. Now enjoying Smithwicks and pizza and an Alfred Hitchcock film.

I hit it with Kroil and will try again. Tomorrow maybe, if I can get up the gumption. Interesting idea using a grinder to make flats instead of double nutting. The studs are not very big and I would be afraid of rounding the flats and then you're totally SOL.

The Ducati shop where I get my parts warned me that the vertical cylinder headstuds could be a PITA. Moisture can sit and work its way into the threads with gravity. Doesn't happen on the horizontal cylinder. Those came out easily, except for the broken one.

Happier days:

lm6y · 01-31-2009, 06:58 PM

An old certified boilermaker taught me this one.

Hit it with a lot of heat,
While it's hot give it some Kroil,
tap it with a hammer, or give it a half turn back and forth,
Keep applying Kroil, and tapping with a hammer or turning it every hour or so.
Let it sit overnight, and it will come right out.

I've watched him take stuff apart that looked like one piece of metal.

PB Blaster is good stuff, but if it's REALLY stuck, I haven't seen better than Kroil.

YTNUKLR · YTNUKLR's Garage

MAPP gas and get a Snap-On CG500 Stud Remover , and the CG5XX insert for the thread you are working with. 10x1.5? Way better than double-nutting, and you can use it for any stud in the future...

Porsche_monkey · 02-01-2009, 06:31 AM

Do you have a stick welder?

jwasbury · 02-01-2009, 11:18 AM

Quote:

Originally Posted by TerryH

Hopefully the thread isn't galled and bringing aluminum with it. Hate to say it, but I can't think of any other reason for it not loosening up. Might need another heli-coil before you're done.

Give the man a cigar. You called it. Seems the threads at the top of the hole were done. Got it out with heat, Kroil, working it both directions, repeat.

Assembled the horizontal cylinder so I could feel good about making some forward progress. Looks like I'm headed back to the machine shop.

jwasbury · 03-08-2009, 09:30 AM

Machine shop put a heli-coil in. I was working on reassembly this AM, and found that the heli-coiled threads must be jacked up slightly because the far end of the stud ends up being 6-7mm out of place...can't get the base gasket on or the cylinder for that matter. What now? I'm not sure its possible to re-do the heli coil at this point. Anyone "been there done that." What are my options?

creaturecat · 03-08-2009, 10:30 AM

Can you get the heli-coil remachined, ground down to being flush?
Is it obviously sitting above? Take it back to the machine shop.