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#17145 03/23/2004 5:17 PM | Joined: Jan 2002 Posts: 2,843 'Bolter | | 'Bolter Joined: Jan 2002 Posts: 2,843 | This has been discussed recently but here's a shot of my gasket showing the darkened ends where it is leaking as compared to the still shinny silver area towards the center. To me either I have the exhaust manifold machined flat or replace the guide pin with a bolt. http://community.webshots.com/photo/127846177/127846450zvjGex Just trying to tighten things up here and there.
Craig My '50 Chevy 3100 5 window, '62-235cu, 3:55 rear My truck ....... Respect The Rust If I'm not working on my truck, '65 m00stang or VW camper, I'm fishing with the wife or smoking Salmon.
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#17146 03/23/2004 5:26 PM | Joined: Sep 2003 Posts: 1,820 Shop Shark | | Shop Shark Joined: Sep 2003 Posts: 1,820 | I still think that Chevrolet didn't finish the job on exhaust manifolds. The guide pin is great for installing the exhaust manifold, but after everything is in place and snugged up, I think the guide pin should be removed and a bolt put in it's place to tighten the ends of the manifold. This may not be so much the case with a one piece manifold, but especially the case with a two piece set of headers.
"Truckin' Around .......... Since 1937!" My name is Joe and I am addicted to Classic Country Music. I just can't hep myself.Operators are standing by to take your calls! Now cruising in the Passing Lane | | |
#17147 03/23/2004 6:14 PM | Joined: Apr 2000 Posts: 499 'Bolter | | 'Bolter Joined: Apr 2000 Posts: 499 | Did you try to loosen the two end bolts? They may be over tightened. I don't have the torque specs handy. On the 250 and 292 the two outside bolts are 20# and the center bolts are 30#
Tube header flanges are simply too weak to be clamped without replacing the guide pin with a stud. It's real easy to get leaks from over tightening tube headers. At least it is when you replace all the bolts and pins with studs/nuts(w/fine treads).
'67 GMC 3/4 292 4spd
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#17148 03/23/2004 7:37 PM | Joined: Jun 2000 Posts: 2,773 'Bolter | | 'Bolter Joined: Jun 2000 Posts: 2,773 | My cure is to take the manifolds off and clean the surfaces. With new gaskets, put a coat of ultra-copper Rtv on both sides. Assemble, tighten, and let sit for 24 hours to cure before starting. Trim off the excess with a knife. Replacing the pin with a bolt does help.
Fred
52 3600
69 C-10
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#17149 03/24/2004 1:13 AM | Joined: Mar 2004 Posts: 37 New Guy | | New Guy Joined: Mar 2004 Posts: 37 | I had a serious exhaust leak with my 235 before I had the head work done, I had napa remove the studs and replace with bolts, it looks alot better I think, and now I hopefully wont ever have to worry about another exhaust leak | | |
#17150 03/24/2004 6:14 PM | Joined: Sep 2001 Posts: 29,270 Bubba - Curmudgeon | | Bubba - Curmudgeon Joined: Sep 2001 Posts: 29,270 | Craig,
I have a NORS exhaust manifold gasket and it is approximately twice as thick as modern replacements. Try two gaskets and use the copper RTV on all sides of the doubled-up gaskets.
This would work with either the original alignment studs or with studs replaced with bolts.
Tim | | |
#17151 03/25/2004 3:53 AM | Joined: May 2003 Posts: 111 Member | | Member Joined: May 2003 Posts: 111 | what the heck. I'll try any cheap answer. My exhaust gasket has never sealed right.
35 + years of rollin' steel!
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