I’ve tried searching for these exact answers but haven’t quite figured this out yet …

Did 914s ever come stock with stainless steel heat exchangers?

If not …
In my searches I saw the name `SSI’ come up a lot in reference to stainless exchangers.
Are all stainless exchangers made by SSI? Or are they just the best?

Are these SSI exchangers? … they are stainless except for the muffler flanges:
http://smg.photobucket.com/albums/v134/sdc...t%20exchangers/

Thanks for any help.

The only stainless HX I know of were by SSI. I bought my first set back about 1976. The early ones did not have the stainless flanges, later ones do. They are no longer in production and new stock is pretty low. They last almost forever, so they are a great investment. Those pictured are 1.7 / 1.8 version.

Pretty much SSI will make more power for your car. They did not come stock. However still legal for C stock SCCA autocross events.

Lighter, better heating, and more power.

914's never came stock with stainless exchangers.

SSI was one manufacturer. Pretty much everyone else was a pretender.
I had a long conversation with John at SSI just last week. If he made more which he is not planning right now, he would redesign them a bit. They would also be expensive. The price of stainless has gone up.

Those are stainless.

Lighter? Maybe. Better heating? Probably not. More power? Doubtful. The Cap'n

WAY lighter. I'm guessing 3-5 lbs lighter each side, with most of the error from all the gunk and oil crud on the old ones making them heavy. Nobody usually brings this up, but they are noticeably louder than stock, I think because the SS walls are thinner. Go get some, then start reading about all the nightmares with broken exhaust studs when doing the swap.

Noisier than the stock heavy steel too.

I have found on some after market heat ex. that you may need to grind off the mounting tabs hieght in order to get them to seal to the heads. Some time the mounting tabs hit the head, so as much as youtighten them, they don't seal. then you over tighten,a dn ruin the head stud.\

also with the copper gasket, heat them up on the stove then allow them to air cool slowly. this willsften them, adn allow them to seal better, allowing the heat ex. to get a bite on them. many gaskets are quenched, or work hardened and thus the heat ex. leaks.

try this to see, take one gasket and heat/then slow cool, then take one you did not do this too. drop both on the floor froma couple feet, the soft one will hit with a thud, and not bounce much, the hardened one will ring when it hits the floor,and bounce much further. if both go thud, then they have been softened already.
They will oxidize and turn black on the stove from the heat, just scrape it off with a screw driver or sand paper before you install them.
not if you were to quench them in cold water after the heating, they will be hard again. the high temp crystal structure is harder, and when you quench them youn lock in that structure. If you slow cool them, the crystal grains have time to grow, making a softer metal. Copper can also be work hardened, basically that is the breaking up of the large soft crystal grains, and making htem small from working it (ie bending, stamping) the slow cool from heat method will soften work hardened metal. Harder copper is more brittle, softer copper more flexable.

When youn work copper, say hammer out a flat plate, you can evetually tear it becuase it hardens and becomes brittle, by stopping every now and then to heat,a dn slow cool, you can keep working it untilthe final shape is reached, without worry of it tearing. If you want it hard, then quench it.

basic metalurgy at work, are not molecules fasinating???

GEEZ, I'm glad I got a Tangerine!!!!!!!!!!

Capt ain't got nuthin nice to say ever.

Yea that's what I do to copper gaskets too. which is still applicable to headers.

Thanks for the replies and info, guys.

No offense meant here, but if you consider a dose of reality "got nuthin nice to say, ever", then so be it. If you have dyno numbers, decibel numbers, comparitive weight numbers, and temp comparison at the heater outlet numbers, then you can try to convince me. Otherwise, I stand by what I said. Show me! If I'm wrong, this forum will be the first place to hear about it. The Cap'n

Indeed! I appreciate the realistic approach to things - particularly when discussing performance options. There's waay too much hype out there. Let's keep this group as down-to-earth as possible.

When you heat them on the stove, what exactly do you do?

Ian Stott
Moncton
Canada

One exception to the more power argument that I would put forth is this; the 75 -76 models had/have a terrible exhaust system that is very restrictive, particularly the California models. While the SSI heat exchanger doesn't "make" more power it would possibly, bar other problems uncover power that is buried under that awful exhaust system.

Save weight and get quicker, thats the symplest performance option to look at.

You don't heat the exchangers, you heat the copper gaskets that go between the exchangers and the heads. Heat them up, let them cool out in the air. This anneals them, and makes the copper soft. It is usually thought of as a way to be able to re-use the copper gaskets; being in place tends to "work" them and make them harder, so they don't seal very well when you reuse them. If you heat them up cherry-red and let them cool, they should be as soft as they were when new.

I still prefer using new gaskets every time, but I may have a bit of a different perspective, as I get them from Pelican...

--DD

Bought my SSI's in '75 - that makes them 30+ years old! Funtion properly - not concerned about a few hp increases (if they exist). Fact is - they work. Each time I remove them I use new gaskets at both ends. Don't think they're louder either.
Look like brand new too ( a little Simichrome does wonders!).

I think SSI made a mistake when they stopped producing these. Buy them once & forget them. They make plenty of heat too!

Only thing I did differently was to use stainless nuts on the head side.

Simply said - they work. No maintenace required.

One more question about the exchangers, just out of curiosity ....

Do these exchangers have cast fins inside them, similar to aircooled Volkswagen heat exchangers?
Or is it just the bare pipes inside the outer shells?

Thanks.

Bare pipes and a sheetmetal sheel.