What's the Best Way to Remove & Install Heat Exchangers?
 

I'm about to pick up the "new" HEs from the place in Canada where I bought the 911T. And I've practically memorized Wayne's great "101 Projects" book and "Up Fixin der Porsche" volumes IX, X and 11. But I can find no recommendations on how to approach this task. What I mean is:

a) If I crawl under the car on jack stands or a lift, and spray copious amounts of Blaster and WD-40 on the 30 million nuts, I'll get most of it on me, BUT, I'd be less likely to get crud in the exhaust ports when I finally pull the headers off.

b) If I pull the engine and support it on an engine stand that allows me rotate the engine upside down, the nuts would be easier to get at, I'd get less WD and Blaster on me, BUT, all that nasty stuff would pour into the exhaust ports as I removed the headers.

c) If I was able to find an engine stand, maybe I could rotate the engine with one bank of the cylinders pointed up as a compromise.

Any suggestions here? What did you folks do?

PS: My M&K muffler was supposed to be here on the 29th but UPS got weathered out!

Tom

Unless you plan on pulling the engine for something else I vote " A ". You don't have to drown the hardware in PB Blaster just keep hitting each of the nuts several times over a 24-48 hour period. Sometimes gently tapping on the hardware with a hammer or a punch helps the penetrant get where it needs to go. As long as it's not a rusty mess you should be able to get the hardware off. If it is a rusty mess it's time for oxy/acetelyne or mapp gas to heat the hardware cherry red to remove. Take your time and you won't snap off the studs. Rush it and you'll be pulling the engine.

Not to hijack, but...leave the WD-40 for your "household projects". PB Blaster is so-so. Try using AeroKroil or acetone/ATF mix. Heat is also your friend.

Heat the nuts and bolts cherry red with Mapp gas or propane. If your fasteners are not rusted round that should do it without using PB Blaster or WD 40. However, I always spray some on after it gets red - it wicks up in the threads real good then. The penetrating fluid will start on fire but don't freak out - it burns off quick. Wear goggles as the liquid will spatter when it hits the heat.

Mapp gas is in the yellow cannister and is hotter but a little more expensive. You can use the same burning tip as you use with propane. Worth the trip to the hardware store.

I vote for another method, which is: "pay someone to do it"

my car has been out of commission with this same project, I sprayed a bunch of Wurth penetrant, Aerokroil and a couple other varieties, many times over the course of 3 days, some studs broke, some were already broken, and even with some incredibly capable extractors (fluted design from facom) that allowed massive amounts of torque, some of these studs defy removal, I've been drilling, tapping and heli-coiling for the past month or so.my car has been out of commission for far too long, I've spent a fair share on tools, parts, beers, cashed in favors from friends, you name it.

the successful removals all included lots of heat in addition to the aerokroil.

Lewis

Danny_Ocean says: Thanks for the tip.

All of you just Google "Aero Kroil" and go to their website. It opens to a fantastic offer on this stuff - two 13oz cans for $12 shipped!!!

Tom

Do not forget the proper tools as well, and there is an amazing amount of threads in regards to this process. If you have a dremel, get it out and ready with a cutting wheel.

As well, with a project such as this, should one be prepared to replace all the exhaust studs, too (if not broken), or just use new fasteners on the old studs?

As well, with a project such as this, should one be prepared to replace all the exhaust studs, too (if not broken), or just use new fasteners on the old studs?

my experience was that the non-broken ones were not worth the hassle of cutting off, drilling, helicoiling.

it would have been nice to replace all the studs, but the ones that were ok, I left alone.

Lewis

:)

Been doing 911 heater boxes here in the rust belt (Northeast) for many years (since 1972). Have your 13mm 6 point socket or 8mm allen ready and use a acetelene torch w a fine tip; heating just the nut until it glows red and then quickly turn the nut. Any resistence & reheat. All other ways will end up with one or more broken studs. BTDT many times.
Theres no way you want to replace studs if you don't have to. Reassemble w new hardware & never-sieze.

Len

:)

BoxterGT says: You do this under the Porsche or with engine removed?

Thanks to all for a great discussion,

Tom

:)

Originally it was a floor jack & jack stands, now its a lift.
Doing every nut nut this way takes 1/2 hr per side to remove, less time to install.
Snap-on 13mm flex 6pt socket works well for this job.
Len

:)

No hijacking but I just did this with the motor on the stand and it was a pain. Pulled several studs when trying to remove the barrel and standard nuts.
The 8mm barrel nuts weren't an issue, getting to the 13mm nuts was the problem. I can't imagine trying to do that with the motor in the car. I stopped just short of cutting up a box wrench and putting a 90* bend in it. I could but the socket on them but I couldn't use the ratchet. Ended up purchasing a thin profile breaker and 1/4 turned them all the way.
Is there any advantage to replacing with allen head bolts? Have any of you replaced with something to make it simpler for future removal?

As mentioned a couple of times, heat is your best bet. Do not rely on Kroil, PB or any other spray. There is a high chance you'll be extremely sorry, and end up wishing you took this advice. Broken studs are NO fun to deal with, so do it right, with a torch.

Get yourself a dremel tool with a flex shat and a couple of carbide bits. I recently took off a heat exchanger using this method and it took about 15 minutes to remove the heat exchanger.

here's a link that gives more detail.

http://forums.pelicanparts.com/porsche-911-technical-forum/336724-dremel-your-nuts-why-do-anything-else.html

the best tool for the 13mm nuts is a (1 piece) universal socket, if you use a universal joint (3/8" drive) attached to a 13mm socket, it becomes too deep, so a universal socket is the key, allowed me to get to just about every nut.

Lewis

What he said, and using a 1/4 inch joint attached to a long 1/4 inch extension is key.

What he said as well.

if you are not going to use the old exchangers, cut them off with a sawsall about an inch or two below the flange. makes things alot easier. get 1/4 drive rachet w/swivil, a 2inch ext, a 13mm box wrench, with a bend in it will get the hard one.

I agree with above, cut the HEs off. The nuts are not easy to get to.

Use the high end penetrants, heat and TIGHTEN first then back them off. Snapping studs is an expensive fix.

The dremel method sounds good. I went Len's route and used an oxy-mapp torch and got all 12 nuts off without incident. Mine looked original, so I was nervous. I spent the better part of a week giving the nut a daily soaking with PB Blaster. When removal day came, I tried a couple of nuts without head "just to see". I applied as much force as I dared without going all out and they would not budge. I broke the torch out and then they came off beautifully. You want to focus the heat on the nut and heat it up fast, to minimize heat transfer through the nut.

The studs all look to be in good shape. Although it would be nice to put fresh studs in there, I think the risks of stud removal on an installed motor do not justify it.

That may have worked for you. For others, it may just lead to heartbreak. One does not know, until the stud twists into 2 pieces.

Removing HEs........
 

I used a sawzall to remove the bottom portion of the old heat exchangers. Makes it much, much easier to access the nuts holding the flanges to the head. Then its penetrating oil, heat, more heat and sometimes the use of a Dremel cut off wheel to split the old nuts. Patience and good tools are mandatory! Good luck with your project.

One other thing, after you have soaked the crap out of them for a few days, tighten just a tad before you start to loosen them. Remember, you must have a certain feel for this, don't use all the force in the world to try to break them free. If it feels like it's not going to budge, stop, apply heat, dremel or what ever and go from there. I did not break one stud on my 72 and used heat on two studs which didn't do a thing so out came the dremel. What works for some, will not work for others.

I always learn the hard way..

Do you guys use anti-sieze when re-installing studs?

I did the same as Mr. Cook... and worked well . Apply heat and by the time you put the torch down, Its time to turn, like others have said, its a feel, dont rush them.

Yes, copius amounts but only on the nuts, not the studs and only the high heat copper stuff.

:)

There's heat, and then there's an ACETELENE TORCH.

The only real way is to get them glowing red then QUICKLY use the Snappy flex socket while they still are hot. If you do it this way, its easy. Any other way you are wasting your time and will break something, taking much longer to fix. We all learn the hard way and sometimes keep doing it the hard way.

Len

:)

Richard003@wind says: and BoxterGT says: Facinating variety of helpful information & opinions here and I'm laser-locked on using heat, but an acetelene torch, if I'm going to do this job, is probably out of the question.

Will a MAPP-gas torch, w/o oxygen be able to get the various nuts hot enough?

Tom

I used to have an oxy-acetylene set up in my old place, however, where I am now I just used the small hardware store MAPP & oxygen set up. I would say this was barely enough for the job. Oxy-acetylene would be better for sure. MAPP gas alone might not be good enough. I needed a few of those orange oxygen tanks to get the job done - not necessarily the most economical approach!

:)

Here's the 1/4 drive version I am referrring to..........

http://forums.pelicanparts.com/uploa...1280956200.jpg

Len

:)

Locktit Freeze & Release Spray
 

As suggested and mentioned later by me, I ordered a couple of cans of AeroKroil that's supposed to be the ticket.

But my neighbor, who has been watching my agony with rusted nuts and bolts, just called and said he was watching the Speed Channel and they had a demonstration of "Locktite Freeze & Release Spray". It has a penetrating oil base but takes the nut down to -40F and works similarly to heat but draws more penetrating oil into microscopic cracks in the rust, etc.

Anybody had good luck with this stuff? I Googled it but can find no local distributors.

Tom

I suspect it's a marketing gimmic (-45F ? :rolleyes: ) and the car shows on Speed are sponsored by the manufacturers of the products, but...can't hurt to try. AeroKroil has worked very well for me.