Heat Exchanger Replacement

[grizzly]

Hello,

First off, let me say that I have become addicted to this BB! I have learned more about my car on this site than any other source. Thanks for, unknowingly, helping me through the choice, inspection, purchase and now maintenance of my car. You guys are great!

I have recently purchased Wayne's book and I will be attempting to replace the left heat exchanger (right side done by po). I have searched through all of the threads on the topic and started soaking the nuts with WD40. I ordered the hex socket, barrel nuts and gaskets from Pelican. I plan on using a MAPP torch to heat the nuts. The car is a 1973 911E with +/- 73,000 miles. My questions follow:

1. Am I NUTS? Should I leave this to a pro?
2. Is the MAPP torch sufficient?
3. Any and all tips, encouragement or discouragement will be greatly appreciated.

Thanks in advance!

Brian

[82SC]

check the tech articles section of this site...my heat exchanger back date article should answer all questions

[cds72911]

I've only done this once, but I used the advice from the board.

I chose to use Liquid Wrench penetrating lubricant, since that is what I had in the garage. Others have recommended a product called PB Blaster. I am not a huge fan of WD-40 unless I'm trying to displace water.

Regarding the MAPP gas question, I do not know. Can you heat stuff cherry red with it? If so, then it seems like it would work. Again, I used oxy-acetylene since I had it in the garage and know it can heat stuff up pretty well.

Mine came off pretty well, but based on the experience of others who have done this a lot more than me those exhaust studs seem to break fairly often on removal.

I have faith that you can tackle it. Go for it!

Charlie

[MAS956]

I second the vote for PB Blaster. I soaked my (HX) nuts in it overnight and that did the trick (after MAPP treatment failed, btw). Anything that smells that nasty MUST be effective! I found it at the local NAPA Auto Parts store. I think it's widely distributed.

[john walker's workshop]

you gotta heat the nuts enough to get them red, at least on one side, or the stud will break. a mini torch won't do that. i've had very little luck with penetrating oil. have some air handy to blow out any small fires from the process.

[T Bird]

Brian
To get the 13mm nuts off, I used a 1/4" drive 13mm 6 point flex socket connected to a 1/4" drive 6" extension. I connected the 6" extension to a 1/4" to 3/8" drive adapter, and attached the adapter to a 3/8" drive breaker bar. This combination allowed perfect access to the 13mm nuts on both the OEM heat exchangers of my 72 T, and sufficient leverage to break the nuts loose.

All of the 13mm nuts and barrel nuts on my car came off without much effort. Give them a try first with penetrating oil (Kroil and Wurth's Rost Off are excellent choices) before you start worrying about applying heat from a torch. You might get lucky and not need the torch, like me. Also, on installation, use a good anti-seize paste on the studs. Take your time!

Good luck.
John

[tmctguer]

i was very lucky..........i replaced the heat exchangers on my '73 911E with 59K miles and all the nuts came off without a problem.

i hope you have the same luck as i did. our 2 cars have close to the same mileage. if you get started, and it looks like you are going to break a stud, i would probably stop, and take it to a porsche mechanic.

[Rot 911]

The MAPP gas will not get the nuts cherry red hot. However for around $40 you can get a mini aceyteline torch kit which uses MAPP and a small oxygen tank which worked quite well for me. The oxygen goes fast so get two of the cylinders.

[cds72911]

It only takes a few seconds with an oxy-acetylene torch to get it cherry red.

The oxy-acet setup is also a handy tool to have in the garage for fabrication work. You can get regulator sets with welding and cutting tips, goggles, regulators, hose, etc for a pretty inexpensive price. Rent some gas cylinders (or buy them like I did) and you always have a torch and gas welder on hand when you need it.

Cheers.