Exhaust/intake manifolds

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   What’s the best way to install these without exhaust leaks? I previously installed the exhaust first then installed the intake and ended up with a nice exhaust leak at the base of the manifold where they bolt up to each other towards the engine. I removed them and bolted them together on the bench, I could clean up the exhaust manifold (which is new) runners with a grinder but I got it to mate up with no gap (checked with a flash light). So I’ll leave them bolted up and attempt to install both at the same time then follow the torque procedure, is this the best way to do it?

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jonb79 Members Profile Send Private Message Find Members Posts Add to Buddy List AMC Nut Joined: Aug/27/2011 Location: Milwaukee Status: Offline Points: 274	Post Options Post Reply Quote jonb79 Report Post Thanks(0) Quote Reply Topic: Exhaust/intake manifolds Posted: May/25/2022 at 5:14pm
	What’s the best way to install these without exhaust leaks? I previously installed the exhaust first then installed the intake and ended up with a nice exhaust leak at the base of the manifold where they bolt up to each other towards the engine. I removed them and bolted them together on the bench, I could clean up the exhaust manifold (which is new) runners with a grinder but I got it to mate up with no gap (checked with a flash light). So I’ll leave them bolted up and attempt to install both at the same time then follow the torque procedure, is this the best way to do it?

Ghostrider_32 Members Profile Send Private Message Find Members Posts Add to Buddy List AMC Apprentice Joined: Apr/06/2022 Location: Pensacola FL Status: Offline Points: 53	Post Options Post Reply Quote Ghostrider_32 Report Post Thanks(0) Quote Reply Posted: May/25/2022 at 5:39pm
	Bolt them together, leave them SLIGHTLY loose. Use a Remflex gasket for the manifold to head, they compress down a good deal and seal really well. Once everytbing is in place, and aligned, finger tighten all manifold bolts to head, then tighten up the exhaust to intake flange to spec. Then go and tighten every bolt in the correct sequence. You want some play at first to align everything, then tighten the play out once everything is in the right spot. Ran into this before on an old 232 a friend had years ago.

FSJunkie Members Profile Send Private Message Find Members Posts Add to Buddy List AMC Addicted Joined: Jan/09/2011 Location: Flagstaff, AZ Status: Offline Points: 4742	Post Options Post Reply Quote FSJunkie Report Post Thanks(0) Quote Reply Posted: May/26/2022 at 12:52am
	The best way is to use NO gasket between the exhaust manifold and the cylinder head, only a gasket where the manifolds meet together. That's how AMC built these engines originally. The head and manifold were machined so flat that they sealed together without a gasket. Of course, that only works so long as no gasket has ever been used. Once a gasket is used, the manifold warps enough that a gasket must always be used. Forget about having a machine shop mill the manifold flat again...they always screw them up worse. The only gasket I've ever found that will successfully seal the manifold to the head long-term is Remflex. The cheap-o Fel-Pro exhaust gaskets burn out the first time you work the engine reasonably hard. The main thing with the Remflex gasket is to not exceed 18 foot-pounds of torque on the mounting bolts or else you might crack the manifold. Forget the Fel-pro blue-colored doughnut gaskets that seal the manifold to the exhaust pipe, too. They also burn out the first time you work the engine hard. Only use silvery-colored doughnuts from Mahle or Walker. As for the bolt tightening sequence, just follow the sequence in the manual. Bolt the intake and exhaust manifolds loosely together and install them on the engine. Then go through the sequence, working your way up to full torque in several steps...unless it's a Remflex gasket and then you stop at 18 foot-pounds.
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jonb79 Members Profile Send Private Message Find Members Posts Add to Buddy List AMC Nut Joined: Aug/27/2011 Location: Milwaukee Status: Offline Points: 274	Post Options Post Reply Quote jonb79 Report Post Thanks(0) Quote Reply Posted: May/26/2022 at 6:01am
	I did order a remflex gasket set, I did use a felpro 2 piece gasket before with the metal style gasket that bolts them together. I’m going to install them as one unit and see how it works out, thanks for the info.

tomj Members Profile Send Private Message Find Members Posts Add to Buddy List AMC Addicted Joined: Jan/27/2010 Location: earth Status: Offline Points: 7539	Post Options Post Reply Quote tomj Report Post Thanks(0) Quote Reply Posted: May/26/2022 at 10:19pm
	Take both manifolds to a machine shop and have them surfaces on their big sander. It works wonders. Every 25 years type thing. That prevents cracking an ear off too.
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