Stainless exhaust pipe rattle won't stop!

J

James G.

Senior Member
I've not resorted to building a "modern rubber/hanger and those "clamps for stainless exhaust" only work for a short while.
QUESTION - what can happen if I just resort to the original clamp Ford used and just clamp the stainless pipe down??? does it put the manifold casting in danger of cracking???
So tired of that dadburn rattle and I'm not about to do away with my stainless exhaust!!
 
Stainless steel grows in length when heated as in the exhaust system. You need to figure
that in. The clamp needs to let it expand.
In some cars the exhaust will grow several inches.
 
Dodge said:
Stainless steel grows in length when heated as in the exhaust system. You need to figure
that in. The clamp needs to let it expand.
In some cars the exhaust will grow several inches.
Click to expand...

Good morning, Dodge. Does S/S "grow" more than regular exhaust pipe? I don't have S/S exhaust, just askin' for my own knowledge and future reference. Thanks
 
In general (10-6 in/in/ deg F)

Carbon Steel (1020) 6.7
Grey cast iron 6.7
Stainless (304) 10
Aluminum 13 Highest
Copper 9.3
Manganese-bronze 11.2
Titanium 5.0 lowest
Gold not listed in the book I checked

In reality these numbers are just guidelines, the thermal expansion of can vary quite a bit depending on the alloy. Silicone for instance reduces the thermal expansion of aluminum significantly. The thermal expansion rate also changes somewhat depending on the temperature of the metal.
(Googled)
 
MMMMM been runnin a S/S aries for years with a re-pop hanger. I did have to fiddle with it I bit but have run for years with no problems.
 
James G. said:
I've not resorted to building a "modern rubber/hanger and those "clamps for stainless exhaust" only work for a short while.
QUESTION - what can happen if I just resort to the original clamp Ford used and just clamp the stainless pipe down??? does it put the manifold casting in danger of cracking???
So tired of that dadburn rattle and I'm not about to do away with my stainless exhaust!!
Click to expand...

I purchased an oversize muffler hanger with woven insulation inside it with my S/S muffler. That lets the tailpipe move when it gets hot but does not rattle.

Bratton's part number 7131. I'm sure other vendors have the same thing.
 
Dodge said:
In some cars the exhaust will grow several inches.
Click to expand...

No way, unless it's made out of rubber.

katy said:
What does "In general (10-6 in/in/ deg F)" mean?
Click to expand...

Sounds like he's describing the coefficient of thermal expansion (CTE) for different metals. 10^-6 is scientific notation, and in/in is the unitless coefficient, per degree F. Another way of looking at it is as microinch per inch per degree F.

So, he's saying the CTE for stainless is 0.00001 in/in per degree F. What I'm seeing elsewhere is, based on the alloy of stainless, linear CTE is somewhere between 5 to 10 * 10^-6 /deg F.

What does this tell us? Someone should just measure their tail-pipe hot and cold based on a known datum and tell us how much it lengthens. I'd guess very little.
 
Aries calls for care with a "not too tight" exhaust hanger even with the regular steel muffler, so apparently it's not just the stainless steel expansion they're concerned about.
 
I have a S/S Aries exhaust on my coupe and a standard Aries on my sedan. Both have the oversized tailpipe hanger for expansion. Both had the flimsy thermal cloth which lasted all of 100 miles. I bought some exhaust pipe wrap from the auto store. Not is as wide as the clamp but not very thick. I could it to fit the circumference of the clamp. Attached it with red RTV and let it dry. Then I attached the clamp with the pipe in place. Snug but still let's the pipe expand. Also rooming my rattle at the end of the tailpipe. Check Amazon for the exhaust pipe wrap. May be cheaper than the auto parts store. Send me a PM if you need pictures.

Brian
 
brianpharmd said:
I have a S/S Aries exhaust on my coupe and a standard Aries on my sedan. Both have the oversized tailpipe hanger for expansion. Both had the flimsy thermal cloth which lasted all of 100 miles. I bought some exhaust pipe wrap from the auto store. It is as wide as the clamp but not very thick. I cut it to fit the circumference of the clamp. Attached it to the clamp with red RTV and let it dry. Then I slid the clamp over the pipe and tighten in place. Snug but still lets the pipe expand. Also eliminated my rattle at the end of the tailpipe. Check Amazon for the exhaust pipe wrap. May be cheaper than the auto parts store. Send me a PM if you need pictures.

Brian
Click to expand...

Auto correct/word substitutions on the tablet makes my post look atrocious. I fixed it in this post.
 
Nathan, thanks for the explanation, but I'm still confused.
I took high school math in the '50s and don't understand the "modern" symbols and ways of expressing mathematical equations.
 
Katy what he is saying is that the pipe expands in length .000001 inches per inch/ degree F. this means that for a length of 10 ft (not a real measurement of a model A muffler) and a temperature increase of 100 degrees F (10 ft =120 inches) therefore, 120 inches X 100 degrees X .000001 =.12 inches expansion in length for the exhaust pipe and muffler. Not very much is it?
 
I understand co-efficient of thermal expansion, but what I'm trying to get my head around is what 10-6 in/in/ means.
10 minus 6 equals 4, that's pretty simple, but then what does in/in/ mean?
 
katy said:
I understand co-efficient of thermal expansion, but what I'm trying to get my head around is what 10-6 in/in/ means.
10 minus 6 equals 4, that's pretty simple, but then what does in/in/ mean?
Click to expand...

"10^-6" is scientific notation for 0.000001. "in/in" is a way of saying "this is a unitless coefficient." Per degree is as stated.

That way, you can multiply your original length of material by a tiny coefficient specific to that material and arrive at what happens during a temperature change.

As midgetracer says;

The material expands in length .000001 inches per inch/ degree F.

Where CTE = .000001, x = 120 in, deltaT = 100 deg:

deltaX = .000001 * 120 in * 100 deg = .12 in.

To double check our logic, the units are:

(in/in /deg) * (in) * (deg) = (in*in/in)*(deg/deg) = in.

Makes sense.

But like I said several posts ago, someone should just measure the end of the tail pipe against a known datum at hot vs cold and see how little it actually moves.
 
A mild steel one moves about 5mm in my experience. Enough that it will permanently distort if the clamp was welded on and not the slip fit kind...
 
Thanks all for the replys to this old fart, I think I'm starting to understand this scientific notation stuff a little bit. I tried a web search and still didn't find much stuff in plain words that I could understand.
 
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