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I'm installing headers for the first time.
I cleaned the edges, and cchecked if they where nice and flat.
Al the edges are perfectly flat.. there is only one spot with some pitting... (see picture).
Do I have to put some high temp sealant on the spot, or don't I have to worry?
It is just in the middle of the two exhaust ports.
It sure wouldn't hurt to smear some High Temp RTV on any questionable spots. But your best bet is laminated metal header gaskets in either aluminum or copper. They will conform to any imperfections thus shown.
Last edited by HeadsU.P.; Apr 6, 2019 at 08:45 AM.
If you're installing tube headers, the flange should have a small raised ring around the tube. A good set of header gaskets, (NOT the ones that come with new headers) will stand the best chance of sealing. BUT you also need to install the headers with the gaskets, tighten the bolts or studs, let it set for a while, then tighten them again. Then retorque every heat/cool cycle for a couple of weeks, then back off to once every couple of weeks. The headers and the head expand and contract at different rates- that's the reason for the frequent retorques. I don't use a "torque" wrench on them, but I do have a long handle wrench that I use and I really put the pull on it. I have a BB, and never had to replace a gasket. I've used that same plan on several SB's too and still blow an occasional gasket. Not near as often as some seem to, but still occasionally have to replace a gasket. I've heard that the dead soft aluminum or copper header gaskets work better. Never tried them.
TimAT is spot on about the retorqueing. Of the 12 header bolts, I had one back off a little after a fresh installation. And using a boxend wrench is easiest for the task at hand.
As far as gasket quality: What's the difference between a $9.95 gasket and a $35 gasket set? You will find out in less than a year.
If you're installing tube headers, the flange should have a small raised ring around the tube. A good set of header gaskets, (NOT the ones that come with new headers) will stand the best chance of sealing. BUT you also need to install the headers with the gaskets, tighten the bolts or studs, let it set for a while, then tighten them again. Then retorque every heat/cool cycle for a couple of weeks, then back off to once every couple of weeks. The headers and the head expand and contract at different rates- that's the reason for the frequent retorques. I don't use a "torque" wrench on them, but I do have a long handle wrench that I use and I really put the pull on it. I have a BB, and never had to replace a gasket. I've used that same plan on several SB's too and still blow an occasional gasket. Not near as often as some seem to, but still occasionally have to replace a gasket. I've heard that the dead soft aluminum or copper header gaskets work better. Never tried them.
Originally Posted by HeadsU.P.
TimAT is spot on about the retorqueing. Of the 12 header bolts, I had one back off a little after a fresh installation. And using a boxend wrench is easiest for the task at hand.
As far as gasket quality: What's the difference between a $9.95 gasket and a $35 gasket set? You will find out in less than a year.
we don't even use gaskets anymore... dirt track trick: high temp silicon is good for 1600*… very thin layer and bam... no more issues and it's on all my vehicles
we don't even use gaskets anymore... dirt track trick: high temp RTV silicon is good for 1600*… very thin layer and bam... no more issues and it's on all my vehicles
we don't even use gaskets anymore... dirt track trick: high temp RTV silicon is good for 1600*… very thin layer and bam... no more issues and it's on all my vehicles
So where would one find this magical 1600* RTV? Best I can find is Permatex Optimum Grey that's only good up to a pathetic 700*
One of the kilns the plant uses, regularly gets up to 2100* and red devil high temp is on every one of the joints of the stainless stacks that transfer the heat elsewhere where it is needed
I bought Sanderson Block Huggers. They state quite clearly NOT to use gaskets due to the precision build of the headers. I've had Sandersons on my '74 coupe for more than five years and have NEVER had to retighten them. Just my $0.02 worth,
Header flanges
