New Project....replace Thermal Reactors (pictures included)

[sean m]

So my next project on the 77S is to finally replace the dreaded Thermal Reactors. After reading so much regarding issues removing, I'm going to take it to a shop and let them handle. Too much for me to deal with (both time and patience) and certainly if a stud breaks off. They are almost 46 years old on the car.

Here's what I've got.....

The actual on my car.....


Now to a possible solution. I don't need heat (live in GA and never use it) and will remove the old rusted heat exchangers and replace with headers.
Anyone have experience with Vertex and this header? Was it plug and play? Possible better solution?


I'm certainly open to ideas from the group.
Let me know as this is something I want to get done this fall.

Thanks

[rwest]

Sean,

Heat is also good for defrost, so really think hard about going without heat exchangers.

And you might decide to take your car on a long trip that includes colder areas.

[Flat6pac]

It’s much nicer when heat is available
The 77 thermal reactor replacement SSIs are best replaced with thick flange 80-83 model years.
You might find the candelabra looking thermal reactor replacements, keeping the original heat boxes.
Bruce

[sean m]

Originally Posted by Flat6pac

It’s much nicer when heat is available
The 77 thermal reactor replacement SSIs are best replaced with thick flange 80-83 model years.
You might find the candelabra looking thermal reactor replacements, keeping the original heat boxes.
Bruce

rwest and Flat 6,
I'm not planning on any long trips in the car....certainly not in the winter. I guess my big concern is WHAT EXACTLY am I breathing through these old, rusted heat exchangers? I know in the last 10 years I've never used either defrost (garage car) or the heat (never take out if it's THAT cold).

I do understand the thought if I'm going to sell it, and make some money, it needs to be correct. My plan is to eventually give to my son and his 3 boys to "play with" growing up and do what they want to it.

Get's back to original thought of just replacing with headers and what I should invest in?

[LJ851]

I’ve lived in the Atlanta area since the early 90s and have driven multiple years without heat and in my opinion heat is definitely a necessity here. I guess if you never drive your car when it’s cold and damp you could get away without it. Driving with frozen condensation on the inside of the windshield is a challenge to say the least !

That being said, the entry price on headers is low enough to give them a shot and see if your habits allow you to drive comfortably without heat.

[sean m]

Originally Posted by LJ851

I’ve lived in the Atlanta area since the early 90s and have driven multiple years without heat and in my opinion heat is definitely a necessity here. I guess if you never drive your car when it’s cold and damp you could get away without it. Driving with frozen condensation on the inside of the windshield is a challenge to say the least !

That being said, the entry price on headers is low enough to give them a shot and see if your habits allow you to drive comfortably without heat.

I guess end of the day, looking at SSI replacements at +$2,000 and never used heat or defrost in 10 years....just thought if my son wants to add back to the car he can always do so.

Really not looking for a power boost, just want to get rid of the heat on the engine from the Thermal Reactors.

[EC900]

Keep in mind the purpose for those Thermal Reactors…an added layer of pollution control that if I’m correct, wasn’t necessary to pass a CA BAR stringent smog test. These create MORE heat to burn off any excess exhaust pollutants. I’m not from CA but they all came with these TR’s and in heavy traffic, the engine tended to get super hot and led to an early engine fail.

If you are not under strict smog testing, stay away from the unnecessary TRs. Upgrade to a Carrera style aux oil cooler, 930 alum valve covers and those SSI/headers will do.

[911 SLANT]

You just missed out on a nice pair of SSI headers for 600.00 here on Pelican. Keep looking you might find another good deal

[sean m]

Originally Posted by EC900

Keep in mind the purpose for those Thermal Reactors…an added layer of pollution control that if I’m correct, wasn’t necessary to pass a CA BAR stringent smog test. These create MORE heat to burn off any excess exhaust pollutants. I’m not from CA but they all came with these TR’s and in heavy traffic, the engine tended to get super hot and led to an early engine fail.

If you are not under strict smog testing, stay away from the unnecessary TRs. Upgrade to a Carrera style aux oil cooler, 930 alum valve covers and those SSI/headers will do.

EC900.......I will look into SSI's. I've already seen some posts from people saying there's used SSI's available.

[john walker's workshop]

Heat exchangers are basically headers with a shell that has air blowing through, both to use as heat and to keep exhaust temps down. Take away the shell and you radiate heat to the engine. At speed, not really an issue, but at idle and slow traffic crawling, the engine will get more heat than with a stock exchanger. Just a thought. A complete SC system would be pretty cheap, as opposed to SSIs.

[sean m]

Originally Posted by john walker's workshop

Heat exchangers are basically headers with a shell that has air blowing through, both to use as heat and to keep exhaust temps down. Take away the shell and you radiate heat to the engine. At speed, not really an issue, but at idle and slow traffic crawling, the engine will get more heat than with a stock exchanger. Just a thought. A complete SC system would be pretty cheap, as opposed to SSIs.

Thanks John....always appreciate your insight. Certainly not looking for performance upgrade so for a similar price and replace the Thermal Reactors seems like the best course of action. I'll start the search.

Thanks all for your thoughts.

[AlKidd]

Why are they called thermal reactors? Do they do something when they get hot?
Anytime I make a change to a car, I always consider its effect on future owners. It may be your sons concern now, but what if it cant be?

[911hutch]

And there will be the consideration of using the proper oil lines and muffler with whichever application you use.

I agree that the most economical approach would be to source a pair of used SC heat exchangers.

And use SC heat exchangers with the traditional euro or aftermarket test pipe, rather than a cat, which are relatively cheap, $100 plus or minus. And used mufflers, also $100 plus or minus, and oil lines for that SC heat exchanger application are pretty cheap. And you would easily have heat if ever needed.

[sean m]

Originally Posted by AlKidd

Why are they called thermal reactors? Do they do something when they get hot?
Anytime I make a change to a car, I always consider its effect on future owners. It may be your sons concern now, but what if it cant be?

AlKidd,
The Thermal Reactors was a bad idea by Porsche. The thought was that they would make the engine hotter to pass emissions in some areas of the US. Unfortunately, they're tough on the engine and lead to a shorter engine life.

[Showdown]

Thermal reactors were an improvised solution to tightening pollution controls in the USA- they gathered the exhaust and super heated it to burn off more of the pollutants, unburnt fuel, etc… the unintended consequence was that as they heated up to burn off the exhaust they inadvertently transferred to at heat to the underside of the engine which in turn caused more dramatic expansion and contraction cycles. On the magnesium cases this expansion and contraction resulted in head studs pulling and a shorter engine life.

It was a prime example of solving one problem and accidentally creating another.

[dannobee]

Many of them were rendered useless by cutting out the inner workings through the outlet.
I'm not saying it's right or wrong, but a few minutes with the cutting torch made them "less restrictive" while still passing the visual part of the smog test.

[Trojands]

I'm about to go through this process with a 1976 911s, were you able to remove the thermal reactors without breaking the studs?
I'm also trying to better understand what to replace the thermal reactors with. If I'm understanding correctly, we can replace with headers from the 911SC?

[Anjizkit]

Originally Posted by Showdown

Thermal reactors were an improvised solution to tightening pollution controls in the USA- they gathered the exhaust and super heated it to burn off more of the pollutants, unburnt fuel, etc… the unintended consequence was that as they heated up to burn off the exhaust they inadvertently transferred to at heat to the underside of the engine which in turn caused more dramatic expansion and contraction cycles. On the magnesium cases this expansion and contraction resulted in head studs pulling and a shorter engine life.

It was a prime example of solving one problem and accidentally creating another.

Cool. Thanks for the insight.


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[Nditiz1]

@trojands they should bolt up fine. Be sure to check thick or thin flange.

As for the exhaust penetrating oil and heat.

[Balisong]

Buy some gloves and maybe do a heated seat project.
Let that bad boy breathe!