Question for Wayne and torches
 

I seem to recall in the 911 engine rebuild book that you don't recommend using a oxy/ace torch to remove the head studs from the block. But when i worked for a porsche repair/race shop they always used torches to take them out and never had problems. If anything, the little buggers came out with 15 sec of heating no prob. So why is it that you are against it?

I think Wayne may have changed his opinion on this (Wayne?).

On my own rebuild, John Walker convinced me to use the Oxy-Ace torch to remove studs. It worked just fine. The case is a huge heatsink, and sucks up heat very fast.

While you might be able to melt a spot on the case if you held a flame on it for an hour or more, the head stud loctite will give up long before that.

I should add that I used a very small tip.

Yeah, i'm going to get a kit from home depot that has a small tip. Full size with small tanks and small tip. Between that, my stick welder, and mig, if i find out that i need another welding or torching piece i'm going to be pissed. I've spent more money on tools than parts on my car so far. Although the 3/4inch torque wrench i have is cool, it's 4-1/2 feet long.

I've never tried it myself but a machinist I know heats up the stud area by using a battery with jumper cables! He puts one end on the case and these other on the stud. Darndest thing I ever heard of.
-Chris

Keep in mind the target audience that the 101 Book is geared towards. You can do a lot of damage with one of those torches, and also messup, or even light your mag case on fire, if you're not careful. I didn't want to recommend anything that potentially dangerous to people who might not know what they are doing.

Proceed with caution here.

-Wayne

The battery thing is pretty scary, as that is a great way to blow up a battery in your face!

-Wayne

Not to mention create an arc and make a really bright and hot fire with a mag case..is that possible?

You can light a mag case on fire. With a torch? Not sure, but it's something I didn't feel comfortable recommending...

-Wayne

Please explain. I know charging a battery generates explosive gases, does discharging it do that too?
thanks,
Chris

I'm half way through my stud extraction and a propane torch is working fine for me. Heat for about 3-5 minutes, stud comes out.

When you are shorting out a battery, you are generating a *tremendous* amount of current drain from the battery. It's not what it was intended to do. While I have not personally had a car batter blow up in my face, I do know that other batteries can explode or deform if they are charged or discharged incorrectly. I'm just guessing, but I think that if you short circuit the battery, you will create many hotspots along the closed circuit (the point of your experiment to begin with), with one potentially inside the battery. In addition, you can electrocute yourself (kill yourself) with a car batter if you're not careful.

I just grabbed this off of a battery charger site:

Batteries generate explosive hydrogen gas, even during normal operation. People have been injured by battery parts flying in an explosion. They can explode under normal operating conditions, such as starting your car. They can explode under abnormal conditions, such as jump starting, or if short circuited by a tool. They can explode in a parked car or sitting on a table.
To help reduce the risk of these dangers and injury, it is of the utmost importance that each time before using your charger, you read and understand this manual, and any warnings and instructions by the battery manufacturer. Follow these instructions exactly.
TO HELP REDUCE THIS RISK:

Wear Personal Protective Equipment
ALWAYS wear complete eye protection (THAT PROTECTS EYES FROM ALL ANGLES).
Avoid Flames and Sparks Near Battery and Fuel
ALWAYS keep flames, matches, lighters, cigarettes or other ignition sources away from battery.
DO NOT put flammable material on or under charger. DO NOT use near gasoline vapors.
Make sure charger clips make good contact by twisting or rocking them back and forth several times. The second clip connection MUST ALWAYS be made away from the battery. ALWAYS plug charger into an electrical outlet AFTER all connections have been made. See OPERATING INSTRUCTIONS.
If necessary to remove battery from vehicle to charge, ALWAYS turn off all accessories in the vehicle. Then ALWAYS remove grounded terminal (connected to car frame) from battery first.
A tool touching both battery posts or battery post and car metal parts is a short circuit and will spark. When using metal tools on or near battery be extra cautious to reduce risk of short circuit, possibly causing a battery explosion. DO NOT drop a tool on battery.
Reduce Explosive Gas (hydrogen)
Before connecting charger, ALWAYS add water to each cell until battery acid covers plates to help purge extra gas from cells. DO NOT overfill. Battery acid expands during charge. After charging fill to level specified by battery manufacturer. For a battery without removable caps (maintenance free battery), carefully follow manufacturer's instructions on charging.
Some sealed maintenance free batteries have a battery condition indicator. A light or bright colored dot indicates low water. Such a battery needs to be replaced, not charged or jump started.
Charge battery with caps in place. Most U.S. batteries are made with flame arresting caps. DO NOT pry caps off sealed batteries. Place wet cloth on batteries with non-flame arresting caps.
Be sure area around battery is well ventilated before and during charging process. NEVER charge in a closed-in or restricted area.
Stay Away From Battery When Possible
NEVER put face near battery.
ALWAYS locate charger as far from battery as DC cables permit.
ALWAYS keep other people away from the battery. They are not wearing safety glasses like you are.
Avoid Contact With Battery Acid
Battery posts may have acid corrosion. DO NOT get corrosion in your eyes. Avoid touching eyes while working near battery.
ALWAYS use a battery carrier. Carrying a battery by hand may put pressure on its ends, causing acid to be forced out vent caps.
ALWAYS have plenty of fresh water and soap nearby in case battery acid contacts eyes, skin or clothing. If battery acid contacts skin or clothing, wash immediately with soap and water. If acid enters eye, immediately flood eye with cold running water for at least fifteen (15) minutes and get medical help immediately.
In very cold weather a discharged battery may freeze. NEVER charge a frozen battery. Gases may form, cracking the case, and spray out battery acid. See BATTERY DATA table.
Avoid Overcharging Batteries
The non-automatic (manual) battery charger models can overcharge a battery if left connected for an extended period of time, resulting in loss of water and creation of hydrogen gas.
Follow Other Manufacturers' Recommendations
Before using charger, read all instructions for, and caution markings on: (1) charger, (2) battery, and (3) related product using battery. Follow their recommended rate of charge.

-Wayne

Just a side note for those that are intrested. I teach welding at a local college. As a good tool I brought in a old 911 Mag case and cut it up. I then demonstrated how to properly repair mag along with the correct filler metals etc. As what not to do I lite a peice of it up to show the pretty colors and how it refuses to go out. This was done with a Oxy/act rig but with a cutting tip rather than a welding tip which most of you probably are useing for stud removal. I think it would be hard to start the case on fire or damage it in any way with just the welding tip but it is possible. That being said this is why wayne was not recomending it as it opens himself up to all kinds of fun issues. Just wanted to add that in.

Best regards
Ben

I understand, thanx for the tips.

Chris, one side note for you believe evrything wayne is telling you. Welding was invented doing exactly what you've explained. It may work but not a good idea. The only time to do something even close is when thawing pipes you can use a welder with a lead at each end and this will cause a short (which a welder is designed to do) this will heat up the pipe to cause thawing. Not exactly what your machinest is doing but along the same lines.

Ben
77 911 3.0
75 914-6 2.7

Using a battery, jumper cables to heat up case studs is just plain dumb. There is no safe way to do it. This is my PROFESSIONSAL opinion. I was the Engineer in charge of advanced battery development for the Tri services back in early 70's.

Besides, since amps are the volume of electrons moving, so to speak, and in a series circuit, the highest amp point is where there's the lowest load. So if there's less resistance in a place other than your block for some reason, it's going to feel some real heat. Or at least that's my understanding of it.

Actually the I is the same everywhere but the R, resistance changes. Heat is proportional to I * I*R in other words the worst conductor gets the hottest. The block is probably the best conductor so it will be the coolest of all. The battery will be boiling ( if the wires haven't melted) and would explode even it it didn't produce hydrogen gas, which it does. Boiling sulferic acid, what me worry?