Removing Heat Exchangers

[cds72911]

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

[Rot 911]

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

[82SC]

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

[john walker's workshop]

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.

[john walker's workshop]

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.

[82SC]

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

[cds72911]

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

[Ted Stringer]

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.

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

[Jdub]

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

[john walker's workshop]

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.

[Leland Pate]

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,