Head Stud Removal
10-14-2002, 08:20 PM
#1
Three Wheelin'
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Head Stud Removal
I dont post here often (I am on the mailing list) but so far have come up with nothing but frustration.
I had a blown head gasket in my 951. I have got the head off. Next up was to replace the head studs with Raceware studs before I put the head on.
I have tried heat the studs until the tops were read-hot. I have tried double nutting the studs. I bought a stud removing tool. I tried using the double nuts while hot. I tried using the stud extraction tool while hot.
I got one stud to turn one quarter trun. I managed to snap the stud removal tool.
I read the instructions from raceware to heat the block up to 250 degree. I didnt do this as it isn't possible to heat the block in the area that the studs are in. I figured heating the snot out of the top of the studs would transfer enough heat into the studs to soften the loctite.
I called loctite technical help and was told that green loctite (which is what i believe the factory studs are in there with) needs to be 450 degree to soften and that recooling will cause the thermosetting plastic to resolidify.
I am at a total loss. If i cannot get the studs out I will put the thing back together and the worst that will happen is I will have another head gasket go out.
I know I should never re-use studs, but I am not concerned about causing more damage trying to remove them that I can possibly solve. Other than this little problem, the head removal was easy. It took me about 4-5 hours total.
Anyone have any great words of wisdom??
TIA
-Dana
I had a blown head gasket in my 951. I have got the head off. Next up was to replace the head studs with Raceware studs before I put the head on.
I have tried heat the studs until the tops were read-hot. I have tried double nutting the studs. I bought a stud removing tool. I tried using the double nuts while hot. I tried using the stud extraction tool while hot.
I got one stud to turn one quarter trun. I managed to snap the stud removal tool.
I read the instructions from raceware to heat the block up to 250 degree. I didnt do this as it isn't possible to heat the block in the area that the studs are in. I figured heating the snot out of the top of the studs would transfer enough heat into the studs to soften the loctite.
I called loctite technical help and was told that green loctite (which is what i believe the factory studs are in there with) needs to be 450 degree to soften and that recooling will cause the thermosetting plastic to resolidify.
I am at a total loss. If i cannot get the studs out I will put the thing back together and the worst that will happen is I will have another head gasket go out.
I know I should never re-use studs, but I am not concerned about causing more damage trying to remove them that I can possibly solve. Other than this little problem, the head removal was easy. It took me about 4-5 hours total.
Anyone have any great words of wisdom??
TIA
-Dana
10-14-2002, 08:32 PM
#2
Done With Sidepatch
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Head studs can be tough due to the constant heating / cooling of the engine...I haven't run into the problem you presently have but I believe heating the area around the stud would be more effective...Heated aluminum expands more rapidly than the stud therefore heating the area around the stud should help your problem by causing the block to expand more than the stud...Hopefully the stud will come out easier...
Otherwise I would take it to a competent machine shop...Best of luck!
Otherwise I would take it to a competent machine shop...Best of luck!
10-14-2002, 08:35 PM
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What kind of stud removal tool are you using? When I pulled mine the tool I had was basically a piece of metal with a hole in it for the stud, and then a rachet point with a lobe attached off center, so that as you put pressure on it and tryed to turn the stud, it gripped tighter. I was able to remove all of them without heating. I did spray some penetrating lube down in the stud holes to try and break down anything that was holding them in first.
10-15-2002, 10:48 AM
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I am not sure what prompts this problem, but sometimes head studs can almost be impossible to remove. Other times they can almost be turned out with finger force.
Bottom line, if you are having problems removing the studs you will need an oxyacetylene torch in order to get the engine BLOCK up to at least 250 degrees. (You can try 2 MAP gas portable torches at the same time, but I have not had good luck with them) I have seen cases where the block had to go alittle hotter than that in order to get the entire area hot. Remember that this aluminum so it takes a lot of heat to get it up to temp. Take your time, use a digital pyrometer and don't break a stud! It is not a good idea to heat the stud as it might cause it to break!
Bottom line, if you are having problems removing the studs you will need an oxyacetylene torch in order to get the engine BLOCK up to at least 250 degrees. (You can try 2 MAP gas portable torches at the same time, but I have not had good luck with them) I have seen cases where the block had to go alittle hotter than that in order to get the entire area hot. Remember that this aluminum so it takes a lot of heat to get it up to temp. Take your time, use a digital pyrometer and don't break a stud! It is not a good idea to heat the stud as it might cause it to break!
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10-15-2002, 03:14 PM
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If you can get some ceramic wool wrap it around the areas you are trying to heat. That should reatain more of the heat.
As was stated don't get the studs too hot. At about 300 to 700F the studs will become more brittle.
Alan
As was stated don't get the studs too hot. At about 300 to 700F the studs will become more brittle.
Alan
10-15-2002, 03:23 PM
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I guess this leaves me with other problems.
To heat the block, I probably need to remove the engine i am guessing.
I dont see any reliable way to heat the block with the engine still in the car.
Even though i have a set of raceware studs sitting on my kitchen counter ( i had to buy them as i found them locally from a shop that wanted to get rid of them for $200...new still sealed in the package) I may just resort to putting the head back on with stock (used) studs.
I figure the most that will happen is that I will blow another head gasket. I can minimize this by truning the boost down from 19psi to about 15-16psi.
I dont want to get into an engine removal right now. That costs a lot. Then its not much harder to go to a 2.8l, etc. Just a "little more" gets very expensive very quickly. I think if i remove the engine it will cost me $5000 (and my head on a platter).
What can happen if i re-use the studs and I can torque them (i.e. they have never been torqued to yield). Should I maybe give them a little more torque (say 10% more..70ish ft-lbs) since used bolts don't have the same clampng power are new bolt for the same torque?
TIA
-Dana
To heat the block, I probably need to remove the engine i am guessing.
I dont see any reliable way to heat the block with the engine still in the car.
Even though i have a set of raceware studs sitting on my kitchen counter ( i had to buy them as i found them locally from a shop that wanted to get rid of them for $200...new still sealed in the package) I may just resort to putting the head back on with stock (used) studs.
I figure the most that will happen is that I will blow another head gasket. I can minimize this by truning the boost down from 19psi to about 15-16psi.
I dont want to get into an engine removal right now. That costs a lot. Then its not much harder to go to a 2.8l, etc. Just a "little more" gets very expensive very quickly. I think if i remove the engine it will cost me $5000 (and my head on a platter).
What can happen if i re-use the studs and I can torque them (i.e. they have never been torqued to yield). Should I maybe give them a little more torque (say 10% more..70ish ft-lbs) since used bolts don't have the same clampng power are new bolt for the same torque?
TIA
-Dana
10-15-2002, 08:54 PM
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Hmm, really depends on how hot you got those studs. Also, did you bugger up the threads at all when using the stud puller?
You can definately do this work without pulling the engine. The easiest way would be to pull off the balance shafts to get the heat more evenly to the where the stud lower threads are. On some of the studs you need to heat the lower thread area via the inner water jacket. If this is a track car you can just do a balance shaft delete kit from Scott Gomes for about $150.
I can't imagine anything worse than blowing the head gasket again, but I would definately not run more than 15psi. You might want to setup your antifreeze resevoir overflow with a clear plastic bottle to better monitor your coolant for pressurization.
You can definately do this work without pulling the engine. The easiest way would be to pull off the balance shafts to get the heat more evenly to the where the stud lower threads are. On some of the studs you need to heat the lower thread area via the inner water jacket. If this is a track car you can just do a balance shaft delete kit from Scott Gomes for about $150.
I can't imagine anything worse than blowing the head gasket again, but I would definately not run more than 15psi. You might want to setup your antifreeze resevoir overflow with a clear plastic bottle to better monitor your coolant for pressurization.
10-16-2002, 10:24 AM
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Heating the block is the key and you don't need to remove the motor to do it. Get two MAP gas torches ($26.00 each at Home Depot) and get someone to help. Direct the flame jet down into the coolant jacket at the stud end. (Is the coolant drained? It needs to be.) There is a Snap-On stud removing collet/handle that's the business. Garrity used to have one he rented. Get the heat on the block at the stud end and apply consistent pressure. You'll feel the stud come free. It's the heat, not the torque.
Good Luck
Good Luck
10-16-2002, 02:46 PM
#12
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Wont heating directly on the block cause very localized heating? I would be affraid that this would ruin the temper of the aluminum.
Of coarse the internals of the engine do run quite hot.
Is the reason two MAP torches are used is just to get enough heat into the block?
How long does it typically take to get the block hot enough in those areas?
-Dana
Of coarse the internals of the engine do run quite hot.
Is the reason two MAP torches are used is just to get enough heat into the block?
How long does it typically take to get the block hot enough in those areas?
-Dana
10-16-2002, 03:07 PM
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[quote]Wont heating directly on the block cause very localized heating? <hr></blockquote>
Hopefully. That's how the studs are going to get broken loose.
[quote] I would be affraid that this would ruin the temper of the aluminum. <hr></blockquote>
Don't know. Garrity assured me that the MAP torch isn't hot enough to damage the block.
[quote] Is the reason two MAP torches are used is just to get enough heat into the block? <hr></blockquote>
Yup. I did it with one, but two would probably make it easier if things are grumpy. Be careful not to melt other stuff (wires, etc.)
[quote] How long does it typically take to get the block hot enough in those areas?<hr></blockquote>
Maybe 2-3 minutes. You know you're heading the right way when oil and junk starts smoking down in the hole the stud sits in. <img src="graemlins/beerchug.gif" border="0" alt="[cheers]" />
Hopefully. That's how the studs are going to get broken loose.
[quote] I would be affraid that this would ruin the temper of the aluminum. <hr></blockquote>
Don't know. Garrity assured me that the MAP torch isn't hot enough to damage the block.
[quote] Is the reason two MAP torches are used is just to get enough heat into the block? <hr></blockquote>
Yup. I did it with one, but two would probably make it easier if things are grumpy. Be careful not to melt other stuff (wires, etc.)
[quote] How long does it typically take to get the block hot enough in those areas?<hr></blockquote>
Maybe 2-3 minutes. You know you're heading the right way when oil and junk starts smoking down in the hole the stud sits in. <img src="graemlins/beerchug.gif" border="0" alt="[cheers]" />
04-29-2003, 10:30 PM
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Head studs can be really, really tough to get out. Somebody said they can be easy as well, and they are correct. After reading what you have tried so far, I doubt they are coming out without taking the block out of the car.
What you should do is forget about the Raceware studs. They don't help at all anyway. The factory studs are not torque-to-yield and are plenty strong except in very extreme cases. Now that I think about it, I can't think of even one torque-to-yield fastener on a Porsche.
Your headgasket blew for some other reason. Address that issue and forget about the studs.
What you should do is forget about the Raceware studs. They don't help at all anyway. The factory studs are not torque-to-yield and are plenty strong except in very extreme cases. Now that I think about it, I can't think of even one torque-to-yield fastener on a Porsche.
Your headgasket blew for some other reason. Address that issue and forget about the studs.