Sheet metal covers on LT1 Roadmaster wagon exhaust manifolds
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jayoldschool
dwardo
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dwardo
Posts : 76 Join date : 2010-06-18
Subject: Sheet metal covers on LT1 Roadmaster wagon exhaust manifolds Mon Jan 03, 2022 9:13 pm
I've been reading all the threads about exhaust manifold bolts and now I'm a bit concerned. I've had an exhaust leak (tick, tick) that turns up about every two years, on the driver side at the rearmost bolt. I've always been able to tighten the bolt up a bit and it has gone away. But for some reason, in my mind, I thought our cars only had three bolts on the manifolds. Maybe I was feeling around in there and only found three? It seems unlikely it would seal with only three but you never know. So I will be checking those carefully and repairing as needed while I have the alternator and steering pump off for my p/s rebuild.
If I have to pull the manifolds, I am going to be sorely tempted to remove those funky sheet metal covers they have. What do they do? Heat shield for plug wires or what? Mine are in good shape and I think they look kind of cool but if they were removed there would be a but more room to work and it would be easy to check the manifolds for cracks.
What is the downside to removing them? I know some have done it because I've seen pictures. But as cheap as GM was in building these cars, they wouldn't have put them on without some good reason. Anybody know? I've been searching this forum and the Impala forum diligently but I can't find a definitive answer. Thanks.
jayoldschool
Posts : 2728 Join date : 2009-06-14
Subject: Re: Sheet metal covers on LT1 Roadmaster wagon exhaust manifolds Tue Jan 04, 2022 10:33 am
Six bolts per side. Keep the covers, they protect the various underhood components.
Subject: Re: Sheet metal covers on LT1 Roadmaster wagon exhaust manifolds Tue Jan 04, 2022 10:37 pm
OK, one vote for keep. Not exactly what I wanted to hear but every vote counts and will be tabulated. Thanks!
Rev Bob
Posts : 502 Join date : 2016-05-24
Subject: Re: Sheet metal covers on LT1 Roadmaster wagon exhaust manifolds Thu Jan 13, 2022 6:49 pm
The covers keep things from melting and/or hardening with the extreme heat from the manifolds. Unless you plan on Jet-Hotting the manifolds for show, there is no reason to remove the heat shields on a driver.
The covers are held on by rivets, some of which go through the casting.
Use the ARP stainless manifold stud kit and say goodbye to the manifold leaks.
Subject: Re: Sheet metal covers on LT1 Roadmaster wagon exhaust manifolds Thu Jan 13, 2022 8:42 pm
if we get real, these are 90s GM long roofers, not ferraris. nobody is going to be drooling over the beauty under the hood. Heat shields are there to keep stuff from melting.
I'd vote for just making things nice and clean and sparkly under there. If you did remove them, i'd do as others suggest and address the issues you create by removing a functional feature and find something more attractive to protect that which these ugly things currently do.
dwardo
Posts : 76 Join date : 2010-06-18
Subject: Re: Sheet metal covers on LT1 Roadmaster wagon exhaust manifolds Thu Jan 13, 2022 9:29 pm
Thanks! you've convinced me. The shields stay. I don't mind the way they look anyhow.
Rev Bob, Serendipity96 and ayilar like this post
sherlock9c1
Posts : 2399 Join date : 2009-05-28 Location : Huntsville, AL
Subject: Re: Sheet metal covers on LT1 Roadmaster wagon exhaust manifolds Mon Jan 17, 2022 3:38 pm
Keep. BUT.. take the manifolds off and have them planed flat. Any machine shop or place with a big belt sander can do it. The outer ports tend to warp away from the head and that's what causes broken bolts. At this age, if you have them planed and put new grade 5 bolts in, you'll never have to worry about it again.
Also, never try to drill out exhaust manifold bolts on these cars. It's a waste of time. Go to a heavy truck repair shop or construction site and ask who their mobile welder/machinist is, and pay him to come to your house and weld out the broken bolts. Trust me on this.
One other trick; take the cats off, replace the manifold to cat studs the Dorman kit, reassemble everything, then loosen and retighten the exhaust manifold bolts; it'll allow the exhaust to get to its optimum position and reduce shear stress on the bolts.
94Woody and Serendipity96 like this post
dwardo
Posts : 76 Join date : 2010-06-18
Subject: Re: Sheet metal covers on LT1 Roadmaster wagon exhaust manifolds Tue Jan 18, 2022 4:31 pm
OK. Also I was reading various posts about cutting the web off the rear of the manifold. I seems like a GM kluge that may do more harm than good but OTOH they've been on there forever and haven't caused any problems that I know of. Thanks.
Subject: Re: Sheet metal covers on LT1 Roadmaster wagon exhaust manifolds Tue Jan 18, 2022 4:43 pm
Cutting the web is a long tested way to help the infamous GM exhaust bolt breakage a exhaust leaks. I think some of the manifolds in the aftermarket like Dorman come without the web. I cut mine on the RMW when I did the rebuild and as far back as the 1980s I had cut the small block Mopar ones for the same reason.
sherlock9c1
Posts : 2399 Join date : 2009-05-28 Location : Huntsville, AL
Subject: Re: Sheet metal covers on LT1 Roadmaster wagon exhaust manifolds Tue Jan 18, 2022 6:09 pm
I cut all the webs on mine as well, on every one of these cars I service. Between that and the planing, you really reduce the stress on the bolts. I also install the longer bolts at every position and stack up a bunch of washers under the heads to allow more length for stretching. I also only torque to 20ftlbs and use loctite to keep them from backing out.
dwardo
Posts : 76 Join date : 2010-06-18
Subject: Re: Sheet metal covers on LT1 Roadmaster wagon exhaust manifolds Tue Jan 18, 2022 11:09 pm
Blue Loctite?
sherlock9c1
Posts : 2399 Join date : 2009-05-28 Location : Huntsville, AL
Subject: Re: Sheet metal covers on LT1 Roadmaster wagon exhaust manifolds Wed Jan 19, 2022 3:36 pm
Anything to keep them from backing out.
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Subject: Re: Sheet metal covers on LT1 Roadmaster wagon exhaust manifolds
Sheet metal covers on LT1 Roadmaster wagon exhaust manifolds