SSI heat exchanger warning Options

[euro911]

Just saw this, and it may explain the leak that I can't seem to find. However, I am not running stainless, but stock exhaust. I don't run heat, so that's not an issue, but the backfire is.

Does this problem happen with the stock steel exhausts too? I assume it would, but this thread seems to focus only on the stainless.

TIA

It's not an impossible issue with stock mild steel pipes, but SS is more susceptible to becoming brittle with the heat cycles.

[EdwardBlume]

Yikes! Forget heat then... (IMG:style_emoticons/default/unsure.gif)

[Phoenix914]

Here is a link to another battery operated CO detector. The one previously linked is discontinued from Home Depot.


http://www.amazon.com/dp/B004Y6V5CI/?tag=g..._sl_s7wc0ilmw_e


Now I'm paranoid about my SS HEs. This isn't something I had thought about previously. Thanks for this thread!

[Spoke]

???

[ThePaintedMan]

That looks just like a set I bought off of Ebay... back when I didn't know any better. In theory that could be fixed. But in practice, it's not worth it... and probably dangerous.

[GaroldShaffer]

Yep, had a perfect looking set of 2.0l exchangers took them off the parts car I could turn the end 180 degrees. (IMG:style_emoticons/default/dry.gif)

[nathansnathan]

Whenever I bolt the heat exchangers to a motor, I check to see if they hold air by putting each cylinder to tdc and blowing into the muffler end of each port. I use a rubber stopper with an aluminum tube through it - something I made, looks like this, kind of.
(IMG:http://www.914world.com/bbs2/uploads_offsite/media.offbeatempire.com-11782-1443219910.1.jpg)

This is also a good test to see if the exhaust is sealing at the head, which can be a problem, and can be done with the boxes on the car, just gotta take off the muffler.

[Johny Blackstain]

Anyone have a clue as to who made them for "AA" back in 1979? Those are the ones I have & they seem to be just fine after 6k miles.

[Dave_Darling]

I'm pretty sure that SSI made all of the 914 four-cylinder ones.

--DD

[SirAndy]

I'm pretty sure that SSI made all of the 914 four-cylinder ones.

(IMG:style_emoticons/default/agree.gif)

[Johny Blackstain]

I'm pretty sure that SSI made all of the 914 four-cylinder ones.

--DD

I'm pretty sure that SSI made all of the 914 four-cylinder ones.

(IMG:style_emoticons/default/agree.gif)

Has the quality of the materials or craftsmanship on the stainless exchangers gone down over the years?
The factory exchangers rusted out after 4 years & nearly killed my Pop from CO poisoning, which is why he bought the stainless ones back in 79.

[Katmanken]

Don't think so. A metalurgist for GE aircraft engines always warned me that my 914 SSI exchanger pipes would rust. He said it was due to the type of stainless tubing used.

He advised using a magnet on the tubing and the air shrouds. One was magnetic and the other was not, This was a guy used to casting turbine blades as a singe crystal and with air passages within. Never run my SSI's so still shiney.

[porschetub]

I posted this last year, heating season is here again. These are big cracks, a tiny one you would not be able to hear would still be dangerous. These are not accident damaged. If you have a set on your car, grab the carbon monoxide detector from home and take a ride with the heat on and windows rolled up. There is a detector used in small aircraft also available. The last photo is how we now test for leaks using air pressure. Brad

The engineering term is "work hardening" the problem exists from constant heat cycling till the SS fractures,you will notice the cracks are @ the start of the bends or in the middle of 2,the tube is under more stress in these areas.
The larger outside radius is always the thinnest part of the tube.
My experiences with this problem have indicated poor quality SS or the incorrect grade used ,old age also plays a part.
To add to the problem closing the pipes in speeds up this issue that's why you don't see cracks outside the heatexchangers,many aftermarket SS systems come with a warning not to use exhaust wrap for that reason,SS pipe get very hot.

[EdwardBlume]

Tangerine or headers.Not the end of the world.

[bretth]

So are you saying that if it is not magnetic it is less likely to fracture? I used to work GRC years ago not with metals though. I believe 304 and up are non ferris.

Brett

Don't think so. A metalurgist for GE aircraft engines always warned me that my 914 SSI exchanger pipes would rust. He said it was due to the type of stainless tubing used.

He advised using a magnet on the tubing and the air shrouds. One was magnetic and the other was not, This was a guy used to casting turbine blades as a singe crystal and with air passages within. Never run my SSI's so still shiney.

[barefoot]

I just checked my 1.7/1.8 SSI's and neither the tubes or the shields are magnetic which means the are 300 series SS, probably 304 one of the least expensive grades and should be good good choices. The 300 series are called 18-8 grades which is 18% Ni and 8% Chrome with most of the balance Iron.
The magnetic grades are 400 series and are just 12% Chrome balance mostly Iron. These grades can be hardened by heat treat so that's what hunting knives are made from.
BTW I pressure tested mine are are OK.
Barefoot

[914ltd]

Hey 'teeners, It's time to bring this up again. There is a lot of good information on this thread about the SSI's. Also keep in mind that CO can impair your judgment.
What might have been the root cause of a 914 accident?
Don't dismiss how dangerous this can be! Brad

[GaroldShaffer]

Little late in bumping this thread. Never to late to check those SSI exchangers you have waiting to install.

[914ltd]

Little late in bumping this thread. Never to late to check those SSI exchangers you have waiting to install.

Thank you Garold. This IS an important thread for 914 owners. Garold or I or someone else should post this, at least, every heating season. Don't avoid using SSI's but be sure to check for CO if you do. Brad Mayeur

[dr914@autoatlanta.com]

Right Dave, John Danials at Stainless Systems made all of the 914 heat exchangers back then, before he sold the operation to Dansk just a few years ago

I'm pretty sure that SSI made all of the 914 four-cylinder ones.

--DD