Exhaust manifold driver side

[ShagWagon]

Success!!

So I took both manifolds to the part store.

Old auto parts guy looks at the bolts the younger guy sold me yesterday for the flange clamp because I bent the original Chinese studs that came with it and shakes his head and says " I can't believe he sold you that" and gets me replacement studs and 2 brass nuts. He said not to use bolts with washers or any washers on the flange at all.

He also says that the copper ones are for headers not manifolds, and that I should just use the ones they sent with it.

So I go home and reinstall it with the gasket dorman sent me instead of the copper one. Tighten down all the bolts, then on the last bolt on the rear I'm lying on my back tightening it and notice that it's not going all the way in. My wrench starts slipping. So I backed off then tighten again. Then I notice that it's all the way tight, but not all the way down. Like a 3/8 gap. So plan was to add 2 or 3 washers to compensate to make it tighten up. I also didn't like that I had slipped some on the head of bolt so I went and removed one from my part rig. It was about 3/8 shorter.......lol

My buddy who helped me re install the engine seems to have gotten the wrong bolt somehow. And it was where you can't see it unless your right underneath it.

I installed the 3/8" shorter bolt from my parts rig and it all went away. That made the difference. What I thought felt like a leak from the flange was probably just blowing out the last port in the small space between them.

Been a pain in the neck for the last 6 weeks!

Now I can properly tune it without contamination to my O2 sensor.

[tgreese]

On the same topic - unless the pipe end is badly eroded, I'd think you could take your manifold to your local automotive machine shop and have it surfaced. As long as the cylinder head face has not been eroded by a long-term exhaust leak, that should restore the factory seal.

Also, I believe the composition gaskets that come with the manifolds - or the ones that FelPro sells, will eventually fail. You're probably going to replace the gaskets in a few years. The factory used the iron-to-iron seal because it's more durable. I think the parts store guy is right about the copper gaskets, that they are intended for headers, but I don't think that should prevent you from using them with manifolds if the manifolds are in good enough shape. However, I would pick the Remflex gaskets over copper or the Felpro type. No personal experience, but I have read nothing but positive reports about them (except for the cost).

[FSJ Guy]

I have used the Reflex gaskets. They work great. A giant PITA to install because they are fragile and don't like being bent. But they seal.

[candymancan]

Dont forget to retighten multiple times over the next week or whatever.. I heard its very important for manifolds with gaskets.

I dunno why they used gaskets on these things. The chrysler magnum engine is all iron cept the intake and water pump and they dont use gaskets for the manifold to block

[letank]

I dunno why they used gaskets on these things

$$$, no need for perfect flatness on either side. The 74 does not have gaskets.... no leaks at current 349Kmiles... the 85 has the gasket, yes it failed, I replaced with the copper gasket, and it needs some retorquing.

The remflex is so thick, it seemed like a royal pita to snake it between the 2 parts...

[ShagWagon]

I feel so stupid that all this time, effort and money spent. And it was only a bolt 1/4" too short that I never noticed.

[tgreese]

I dunno why they used gaskets on these things

$$$, no need for perfect flatness on either side. The 74 does not have gaskets.... no leaks at current 349Kmiles... the 85 has the gasket, yes it failed, I replaced with the copper gasket, and it needs some retorquing.

The remflex is so thick, it seemed like a royal pita to snake it between the 2 parts...

I thought that Jeep never used exhaust gaskets on these engines. Certainly the gaskets were gone by '72 when I started hanging around the dealership mechanic's bay, and Jeep replaced the composition doughnut gaskets with steel soon after. My impression was the composition flat gaskets sold by FelPro and others were 100% an aftermarket thing. Because they do fail after a while ...

[ShagWagon]

I learned that people use gaskets because their manifolds/heads surfaces get warped and won't seal up to make up the difference. Has to be planed which can be done by hand with a thick window glass and some Emory cloth.

I took the copper one back out and put in the thinner one that came with the dorman manifold. Just for insurance.

I most likely didn't need one at all because it was newly rebuilt engine and brand new manifold in theory....

[candymancan]

My 90 has a gasket and it leaks i had to use a sealer on the leak between it and the head because my bolts look too scary rustemy for ne to attempt to take it off.

Also other gws ive seen like an 88 87 ect all had gaskets

The gasket on mine is steel or something because the parts hanging out are rusted badly