NastyZ28 Forum



Go Back   NastyZ28.com > Body & Chassis Restoration > Original Drivetrain Topic
User Name
Password

Reply
 
Thread Tools Display Modes
Old 04-23-2012, 11:45:46 PM   #1
tms71z28
Member
 
Join Date: Apr 2005
Location: CO
Posts: 47
Smog tube pipe inserts

Has anyone removed the original smog tube from the exhaust manifold from a 1970-71 Z28?

Do you know the length of the pipe insert?

The GM pipe insert is 3 1/8" long.

Years ago I had an auto shop Install my original exhaust manifolds and the smog tubes. I supplied the GM pipes for the tubes. When I removed the smog tubes and the pipes recently they were less than 2” long. I’m not sure if the auto shop cut them down or something else changed the length.

Any information would be greatly appreciated.

Last edited by tms71z28 : 04-24-2012 at 12:48:40 AM.
tms71z28 is offline   Reply With Quote
Old 04-23-2012, 11:58:07 PM   #2
mgoad1971
Lifetime Gold Member
 
mgoad1971's Avatar
 
Join Date: Jul 2011
Location: Houston, Texas
Posts: 2,380
Assuming this is a 1980-81 Camaro California car???
__________________
"The glazed-over eyes of students dutifully taking notes, the desperation to memorize facts for a test, the hand raised in the middle of a lecture to ask only, “Will that be on the exam?” These are all the symptoms of a failing educational strategy.”
-Stuart Firestein


Camaro Diagrams
GM Part# Lookup
Fuel Types FAQ
Why swapping MTBE to Ethanol in gas is stupid...
mgoad1971 is offline   Reply With Quote
Old 04-24-2012, 12:02:09 AM   #3
twozs
Veteran Member
 
Join Date: Aug 1999
Location: hopewell jct ny
Posts: 6,693
Quote:
Originally Posted by mgoad1971
Assuming this is a 1980-81 Camaro California car???
why , his name is tms 71Z28 and his profile seems to verify that .
__________________
P.I.T.A
twozs is online now   Reply With Quote
Old 04-24-2012, 12:14:53 AM   #4
mgoad1971
Lifetime Gold Member
 
mgoad1971's Avatar
 
Join Date: Jul 2011
Location: Houston, Texas
Posts: 2,380
I don't judge a book by its cover .
Smog tubes are different for BBC than SBC. I was just reaching for more info.
__________________
"The glazed-over eyes of students dutifully taking notes, the desperation to memorize facts for a test, the hand raised in the middle of a lecture to ask only, “Will that be on the exam?” These are all the symptoms of a failing educational strategy.”
-Stuart Firestein


Camaro Diagrams
GM Part# Lookup
Fuel Types FAQ
Why swapping MTBE to Ethanol in gas is stupid...
mgoad1971 is offline   Reply With Quote
Old 04-24-2012, 02:19:21 AM   #5
Bob R
Moderator
 
Bob R's Avatar
 
Join Date: Jan 2000
Location: Flower Mound, Texas
Posts: 4,217
Ran into this problem years ago. The Smog Tube inserts (the ones that go into the exhaust manifold). The replacements from GM are slightly longer than the originals. Not sure of the exact length at the moment. However if you use the current replacements (assuming they are still available and have not checked) will rub up against the exhaust valve stem. So what you have to do is just grind them down a bit. I honestly cannot remember how much I had to take off since it was years ago. It wasn't a whole lot but you definitely do not want it rubbing up against the valve. Not good.
Bob R is offline   Reply With Quote
Messages from Our Sponsors !
Awesome NastyZ28.com Merchandise !!

T-shirts, wearing apparel

Drinkware, Mouse Pads, Decals

Old 04-24-2012, 09:16:08 AM   #6
COPO
Lifetime Gold Member
 
COPO's Avatar
 
Join Date: Sep 1999
Location: Ontario Canada
Posts: 13,347
I'll measure mine. When GM still had them before selling them all off to a US Co, I purchased one since they were $12. ea. I just cleaned them and reused mine.


The new one was the same as my originals from my 70.
__________________
Mark
My 70 Z28 Web Site http://www.nastyz28.com/~copo/index.htm
Twitter
Qjet rebuilt etc http://www.nastyz28.com/~copo/qjet.zip
The angle of the tangle X's the heat of the meat = the mass of the ASS.
COPO is online now   Reply With Quote
Old 04-24-2012, 01:26:31 PM   #7
70COPO
Lifetime Gold Member
 
Join Date: Dec 2003
Location: Chillicothe Ohio
Posts: 978
I had to shave mine back a bit also. Perhaps the cast depth of the insert hole on the manifold could have some casting variation?
70COPO is offline   Reply With Quote
Old 04-24-2012, 07:50:55 PM   #8
Bob R
Moderator
 
Bob R's Avatar
 
Join Date: Jan 2000
Location: Flower Mound, Texas
Posts: 4,217
I just measured an original from a 1973 Z28. It is 2.691 long. Anything longer than this will contact the exhaust valve stem.
Bob R is offline   Reply With Quote
Old 04-25-2012, 12:37:47 AM   #9
Smokey34
Veteran Member
 
Join Date: Aug 2008
Location: Texas
Posts: 344
Not sure if this will help or add confusion, but I took a pic and measured one that I got from Bill Hodell for a 1970 BBC. They are almost exactly 2-1/2" long.

BBC smog inserts from Bill Hodell
__________________
1970 SS/396
1991 Z28/5.7
1999 Z28
Smokey34 is offline   Reply With Quote
Old 04-25-2012, 09:11:48 PM   #10
DCL70
Veteran Member
 
DCL70's Avatar
 
Join Date: May 2007
Location: Merrimack, NH
Posts: 1,141
The smog tube shown in the photo below is from a 1972 LH exhaust manifold cast # "3989041" dated "F 23 72" (June 23 1972).
The tube measures 2.68" long with a diameter of 0.32".

Dave
__________________
Originally from "Narragansett No. 6" in the Bay State

1970 Camaro SS350 w/Muncie
(real long term project, 1990 to ????)
1966 Corvette 327 w/Muncie (1980 to 1995 restoration)
1994 Camaro Z28 w/6-speed M.T.
1998 Chev. S10 w/4.3L & 5-speed

Last edited by DCL70 : 06-01-2012 at 07:59:06 PM.
DCL70 is offline   Reply With Quote
Reply




Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

vB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Forum Jump



Copyright © 1997 - 2014 NastyZ28.com Inc.
Powered by vBulletin Version 3.5.0
Copyright ©2000 - 2014, Jelsoft Enterprises Ltd.