Homemade PEMS
The flange WILL warp if you run continuous welds. It'* a well-known fact in the header community, and this application is no different.
I STRONGLY suggest using gaskets for re-installation, and still caution against header wrap. Lots of horror stories, and our manifolds are already prone to cracking. The gaskets will allow them to flex a little more, which may prevent further cracking, and they will also help to seal a warped, or slightly warped flange.
I used 1500° paint also, and it immediately blacked out after 5 minutes of idling, but the ceramic is SUPPOSED to still be there even though they discolored.
I STRONGLY suggest using gaskets for re-installation, and still caution against header wrap. Lots of horror stories, and our manifolds are already prone to cracking. The gaskets will allow them to flex a little more, which may prevent further cracking, and they will also help to seal a warped, or slightly warped flange.
I used 1500° paint also, and it immediately blacked out after 5 minutes of idling, but the ceramic is SUPPOSED to still be there even though they discolored.
I wonder: given the amount of work it takes to change exhaust manifolds, how do PEMs compare to actual headers on a L27 in terms of performance increase...And who makes headers for my '93 SE?...For that matter: can I buy PEMs ready to bolt on?
My original EM'* were stressed crakced and I butchered them trying to weld them up. I purchased a set from a junkyard for $74 shipped, but had to do a little shopping to find them. They were stressed cracked in the same place. I sent them off to be welded, ceramic coated inside and out, and powder coated. There went a quick $250. Then I ported them myself which took a few hours. I splurged some on the ceramic and powder coating, but the real enhancement came from the port matching. BTW, the powder coating hasn't suffered a bit from the heat.
Will i understand that the manifold CAN be warped, but if it is welded right it can be done without warping. The first set i did i had welded all the way around each port and installed them with felpro gaskets and have absolutely no warp or leaking problems. By the way the manifolds do come with factory gaskets, the early 90'* have an extremely thin black gasket that doesnt even appear to be there when you take them off, but its there. So i recommend a good sanding on the manifold flanges and on the heads to clean up the mating surfaces to ensure a good seal.
Originally Posted by jgs11
By the way the manifolds do come with factory gaskets, the early 90'* have an extremely thin black gasket that doesnt even appear to be there when you take them off, but its there. So i recommend a good sanding on the manifold flanges and on the heads to clean up the mating surfaces to ensure a good seal.
EDIT: There is on the 93 NOW, but there wasn't.
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From: Yulee , FL ___ SEBF Survivor

Originally Posted by willwren
Originally Posted by jgs11
By the way the manifolds do come with factory gaskets, the early 90'* have an extremely thin black gasket that doesnt even appear to be there when you take them off, but its there. So i recommend a good sanding on the manifold flanges and on the heads to clean up the mating surfaces to ensure a good seal.
EDIT: There is on the 93 NOW, but there wasn't.
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