Removing Heat Exchangers
 

Hi all,

I read the Tech Article and searched the archives. I'm about to take this one on.

Regarding heating/cooling cycles of the studs - is MAPP gas necessary of will oxy/acetalene work? I do not have a MAPP gas setup, but I do have an oxy/acetalene setup.

Do you have any other tips for avoiding breakage of the studs?

Thanks,
Charlie

Actually oxy/acetalene, with a rosebud tip, works better than MAPP. Be prepared to have a stud break. They are old and inspite of all you do, it just happens. Good luck.

Kurt V
72 911E

I was the one who wrote th article...the oxy/ace worked fine for me...didn't even use the rosebud tip (i have no idea what one is being a newbie)

I just used the tip of the blue flame which is the hottest part...held there for about 4-5 min

feel free to email me if you have ques or probs

a rosebud tip would set the whole car on fire. that's a big hot flame. a small oxy/acet tip is generally used to heat each nut red hot. takes less than a minute. do one at a time, and have your tools ready so you can turn them while they're still red. a long 8mm allen socket for the allen nuts, and a 13mm wobbly and extension for the regular nuts. 3/8 drive, of course. i rarely break one with this method. if it starts getting tight as they're being removed, stop and reheat. have some fire prevention just in case.

a rosebud tip would set the whole car on fire. that's a big hot flame. a small oxy/acet tip is generally used to heat each nut red hot. takes less than a minute. you don't want to get the stud red hot, just the nut. do one at a time, and have your tools ready so you can turn them while they're still red. a long 8mm allen socket for the allen nuts, and a 13mm wobbly and extension for the regular nuts. 3/8 drive, of course. i rarely break one with this method. if it starts getting tight as they're being removed, stop and reheat. have some fire prevention just in case.

for the hex nuts use a 1/4" drive u-joint socket(not one that attaches to a u-joint, one already attached, there are some REALLY tight spots, and 1 or two nuts you will just have to use a open end wrench

Thanks all.

The one thing I especially appreciate is the point about heating the nut, not the stud. I did not catch that detail in the other things I read.

I'll have to get one of those universals with the socket built in. All of my universal joints are separate units and probably wouldn't fit in the available space.

Thanks,
Charlie

When you put it back togeather, use some anti-seize on the studs. This will save you or the next person a lot of trouble as the studs will come off with a little work but no heating required.

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Ted Stringer
nuke3@juno.com
'84 911 Targa aka pocketrocket

Using the Smiths torch guide, you ought to be using a number 3 or 4 tip max. The rosebud is a heavy-duty tip that is akin to a shower head, though much smaller. The rosebud is great for pre-heating large areas but for fine work such as what you are doing you need to address the area with a small tip whose flame has the classic "one flame shape inside the other" setting. Hiss should be minimal. BATHE the area with a semi-soft flame, and do not red-hot the stud.

Good luck, this one is a bear from what I am told.

Jw

the trouble with 1/4 drive extensions is that they are too flexy for this job. the hot nuts still need a good snap to get them loose.1/4 drive ratchets and breaker bars are also too short for much leverage. a snapon 3/8 drive 13mm 6 point wobbly on a 10" extension works well.

Hey, just a note on removal of those pesky little hex nuts.
Instead of buying the fancy Porsche tool, go to Sears and buy a set of Craftsman T-handle allen wrenches. The big ones with the rubber handles. The 8mm one will get up inside the heat exchanger with no problem. For torque power just get a piece of pipe that will slide over one side of the T-handle. Use this for turning power. I removed all of my studs using this method and only snapped one stud...and I wasn't even using heat.

good luck,