Are these thermal reactors?

gbonifie · 07-09-2007, 07:55 AM

Car is 1975 911S. This is a thermal reactor in the picture, isn't it? PO claims the reactors were removed years ago, but this tube with three inlets to one outlet sure looks like one to me.

Thanks

RoninLB · 07-09-2007, 07:59 AM

my stock reactors looked different than that. They were replaced with so called headers. They were really just a tube replacement and very inefficient.

find a set of used SSI.

beepbeep · 07-09-2007, 08:08 AM

Those are so called "stud pullers"

Remove them and replace with headers...

gbonifie · 07-09-2007, 08:21 AM

Thanks guys.

RoninLB -- Do you think these are most likely the headers you speak of? They do seem pretty thin compared to the pictures of reactors I've seen on the forum. Was their purpose to more efficiently dissipate heat than the thicker walled reactors while still passing smog requirements?

I agree that some SSI's are in order.

tonythetarga · 07-09-2007, 08:32 AM

right out of Pelican Parts list:

Your photo looks similar. They were typically replaced by something called a "w" pipe (could not find a photo of one) but they bolt up un place of the reactor and connect to the heat exchanges. The best overall solution is to go to a later style heat exchanger or SSI system.

ossiblue · 07-09-2007, 08:50 AM

gbonifie,
Though the pic looks like the thermal reactor, I believe it's actually the "W" pipe that replaces it. Not positive as I've never seen one, but the reactors seem to be more substantial with shorter attachments to the exhaust ports.

gbonifie · 07-09-2007, 08:56 AM

Thanks all --

ossiblue -- I agree, I think this is the W pipe so I guess the PO is correct. I was expecting something that looked more like SSI's. I guess that will be my first project.

tonythetarga · 09:26 AM

Actually the W pipe is "W" shaped and resembles a conventional exhaust manifold. Looks to be cast iron as well. That thing could be a home-made piece. Pelican has a part number for the Reactor replacement by Bursch but no picture. I'll try and find a picture and post what it looks like.

edit: check this classified thread.
Bursch Thermal Reactor Replacements

ossiblue · 07-09-2007, 10:56 AM

Good catch, Tony. gbonifie's photo appears to be fabbed replacements for a header--probably to fool the smog checkers yet not produce the killer heat of the reactors. Anyway, now is the time to change out the exhaust and simplify.

RoninLB · 07-09-2007, 11:37 AM

I have a set of the TR tube replacements. They're stashed in the attic. They look like a set of headers, not what was posted above.

RoninLB · 07-09-2007, 11:40 AM

Quote:

Originally posted by gbonifie

. Was their purpose to more efficiently dissipate heat than the thicker walled reactors while still passing smog requirements?

the tube replacements were smog legal in the very early days. Later on they became smog illegal.

sean m · sean m's Garage

gbonifie.....those are the thermal reactors. Mine is a '77s. I haven't attacked mine yet (a little scared of the stud problems)
Let me know what you do.

Sean

gbonifie · 07-09-2007, 12:43 PM

As always, this forum is a wealth of information.

Tony -- thanks for digging that up. I guess it makes sense for the W pipe to be shaped like a W.

Sean, they sure do look like what is on your car. If that's the case, maybe they are the thermal reactors. It's kind of confusing. My exhaust studs look pretty rusted, and I'm a little afraid of trying this repair myself. If an exhaust stud breaks, is that a mandatory engine drop, or can it be fixed from below on a lift?

I'm certainly getting a mid-year education.

RoninLB · 07-09-2007, 01:16 PM

personally i'd go to a 911 shop and let them torch it off.

removing reactors DIY is a problem waiting to happen imo.

tonythetarga · 07-09-2007, 01:42 PM

Quote:

Originally posted by gbonifie
As always, this forum is a wealth of information.

If an exhaust stud breaks, is that a mandatory engine drop, or can it be fixed from below on a lift?

No engine drop required BUT the studs will have to be drilled out if they can't be persuaded to come out. I'd suggest it be done at a shop on a lift. This should be done anyway and fresh studs put in. Make sure you have whatever exhaust you're going to put on available and new exhaust gaskets. If you go with SSI's you will need to reroute oil lines to the engine and thermostat, about another $250 bucks worth of consideration, not to mention the 2 in muffler. You can put in a newer stock exhaust system with heat exchangers. Your new studs will have to match either the thin flange or thick flange of the heat exchangers.

sean m · sean m's Garage

Ditto what Ronin and Tony said......take it to a shop to have them done. When I first got my car used the search button on the "thermal reactors", scared the s*%t out of me.

Not something I want to screw up. Once again, let me know what you decide on because I've got to do it as well.

Good luck.

john walker's workshop · 07-09-2007, 03:07 PM

not TRs. just a squared off version of the more common W shaped replacements. TRs are way larger and almost completely block the nuts that attach them to the heads.

gbonifie · 07-09-2007, 06:49 PM

John,

Thanks for the definitive answer! Your posts have helped me a lot in the past.

I'm taking the car into the shop to have the ride height set and will check into the cost of installing the SSI's. Thanks for the advice guys. Sean, I'll let you know what I decide and will let you know how it turns out.

I'll post some pictures of the car soon.

RoninLB · 07:31 PM

if you're going thru the bs of an exhaust mod on a good engine plan on doing a very nice install all at once.

some of those TR engines can perk up real nice. A full mechanical ignition advance is icing on the cake.

ps: I did a quickie look for my TR. I was going to pic and weigh them. They weigh as much as a dutch oven... ng

frankc · 07-09-2007, 07:46 PM

Those sure do look like the Thermal Reactors I pulled off my 77 - but that was 20 years ago so I can't be sure. And the "W" pipe replacement (from Bursch I think) I used until I installed SSIs looked like a header with unequal length tubing (outer two pipes were longer) that fed into the stock heat exchanger. I may still have the "W" headers in a box somewhere (I sold the TRs). If I find them I'll snap a photo and post.