740 CA smog test and exhaust work

nosajnil · 08-21-2012, 03:21 AM

as you can see in the picture, I need to fit this new catalytic converter, it was almost going to fit in at first, so I expanded it, but the expander cannot go further into the narrower section, and this is as far as I can go;
is there some kind of "quick and dirty" way to seal this up (with no exhaust leak), while last long enough to pass the smog check, and can be easily taken apart?
since I borrowed the CAT,I can't modify it or mess it up
can duct tape withstand the heat?

if there is actually exhaust leak AFTER the catalytic converter, will it effect the smog result in a bad way?

what's a good way to hold the pipe in place while turning the expander? ( it's good thing they have this U section "over the axle" part, which helps hold it in place.

745 TurboGreasel · 08-21-2012, 05:14 AM

Impact wrench on the expander....grease it well, an it might not break, but they usually do.
On a more practical note, as long as the probe can ft in the furthest upstream hole which is downstream from the cat, you are fine for smog. no leak upstream of the cat is accepted.
Or you cold tie a wet newspaper around the seam for the test.

nosajnil · 08-21-2012, 01:46 PM

the tool might break? or the pipe might break?

why newspaper? any special reason?
it won't dry up and catch fire half way of the test right??

will the leak be fresh air going in? or exhaust leaking out of the pipe?

when I was younger, I have thought if I can divert some of the exhaust to somewhere other than the tailpipe
then where the probe is measuring would be "lowered", but I guess it's based on percent rather than quantity right?

745 TurboGreasel · 08-21-2012, 03:28 PM

%, and it checks for sample dilution. otherwise changing from 2" to 3" pipes would cut your emissions in half.
Working in the glass shop, I handled 1500* glass without gloves, only 1/2" of paper the first few pages burn through.
My HF expanders never lasted very long, esp, the 3"
exhaust comes down the line as a pulse, mostly exhaust leaks out, but some air is drawn in behind it.
A hose clamp and some putty would fix your leak there too.
on further inspection, you have a dent from the clamp, you can work that out with a hammer, but it will take a bit.

survolvo · 08-21-2012, 04:29 PM

I've used this before to rig up the cat on my Yota to pass smog. It will seal it all up, and can be cut off with a razor knife. It will leave a little residue on the pipes, but it can be removed with some sandpaper.

http://www.autozone.com/autozone/acc...er=827123_0_0_

nosajnil · 08-21-2012, 05:35 PM

Quote:

Originally Posted by survolvo

I've used this before to rig up the cat on my Yota to pass smog. It will seal it all up, and can be cut off with a razor knife. It will leave a little residue on the pipes, but it can be removed with some sandpaper.

http://www.autozone.com/autozone/acc...er=827123_0_0_

I was thinking of that and saw it at the shop!
will it seal up (since it's hard right now)?
and you are it can take ff with razor knife "relatively easy"? (since it's kinda hard to work on the floor and car jacked)
reminds me of pre-impregnated composite fibres material...and feels like it will cure really hard??
or if I time correctly, it will cure a bit to seal up for the test, but not so hard to take it off
(

now you know how lazy I am , always thinking of all these stuff)

survolvo · 08-21-2012, 06:43 PM

Its soft and pliable out of the package. Wrap it nice and tight a couple inches past the seam on either side and it will seal up after the exhaust pipe gets warm. It becomes hard and shrinks when heated.

I was able to get it off fairly easily by making a few slices parallel to the pipe. Than running the blade under the wrap. There will be little pieces stuck on, but those can be chipped off with the razor and the smaller bits can be removed quickly with some 80 grit sandpaper.

Get a pillow and it will be much more comfortable.

08-21-2012, 03:21 AM	#1
nosajnil Board Member Join Date: Feb 2007 Location: Los Angeles, CA	CA smog test and exhaust work as you can see in the picture, I need to fit this new catalytic converter, it was almost going to fit in at first, so I expanded it, but the expander cannot go further into the narrower section, and this is as far as I can go; is there some kind of "quick and dirty" way to seal this up (with no exhaust leak), while last long enough to pass the smog check, and can be easily taken apart? since I borrowed the CAT,I can't modify it or mess it up can duct tape withstand the heat? if there is actually exhaust leak AFTER the catalytic converter, will it effect the smog result in a bad way? what's a good way to hold the pipe in place while turning the expander? ( it's good thing they have this U section "over the axle" part, which helps hold it in place.

08-21-2012, 05:14 AM	#2
745 TurboGreasel Board Member Join Date: May 2005 Location: Freedom CA	Impact wrench on the expander....grease it well, an it might not break, but they usually do. On a more practical note, as long as the probe can ft in the furthest upstream hole which is downstream from the cat, you are fine for smog. no leak upstream of the cat is accepted. Or you cold tie a wet newspaper around the seam for the test. __________________ . . No remorse . . . . No regret . . .War without end Feedback

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08-21-2012, 01:46 PM	#3
nosajnil Board Member Join Date: Feb 2007 Location: Los Angeles, CA	the tool might break? or the pipe might break? why newspaper? any special reason? it won't dry up and catch fire half way of the test right?? will the leak be fresh air going in? or exhaust leaking out of the pipe? when I was younger, I have thought if I can divert some of the exhaust to somewhere other than the tailpipe then where the probe is measuring would be "lowered", but I guess it's based on percent rather than quantity right?

08-21-2012, 03:28 PM	#4
745 TurboGreasel Board Member Join Date: May 2005 Location: Freedom CA	%, and it checks for sample dilution. otherwise changing from 2" to 3" pipes would cut your emissions in half. Working in the glass shop, I handled 1500* glass without gloves, only 1/2" of paper the first few pages burn through. My HF expanders never lasted very long, esp, the 3" exhaust comes down the line as a pulse, mostly exhaust leaks out, but some air is drawn in behind it. A hose clamp and some putty would fix your leak there too. on further inspection, you have a dent from the clamp, you can work that out with a hammer, but it will take a bit.

08-21-2012, 04:29 PM	#5
survolvo Board Member Join Date: Jul 2011 Location: Big Sur, CA	I've used this before to rig up the cat on my Yota to pass smog. It will seal it all up, and can be cut off with a razor knife. It will leave a little residue on the pipes, but it can be removed with some sandpaper. http://www.autozone.com/autozone/acc...er=827123_0_0_

08-21-2012, 06:43 PM	#7
survolvo Board Member Join Date: Jul 2011 Location: Big Sur, CA	Its soft and pliable out of the package. Wrap it nice and tight a couple inches past the seam on either side and it will seal up after the exhaust pipe gets warm. It becomes hard and shrinks when heated. I was able to get it off fairly easily by making a few slices parallel to the pipe. Than running the blade under the wrap. There will be little pieces stuck on, but those can be chipped off with the razor and the smaller bits can be removed quickly with some 80 grit sandpaper. Get a pillow and it will be much more comfortable.