258 Exhaust Manifold Flange differences?!?

So I finally got the manifolds painted and installed. One of those jobs that seems simple, but just can't go right. I was having the hardest time getting the 2 short bolts in the center of the exhaust manifold to start to thread. Finally got those in there and on to the last bolt to start by hand. Turns out it is was going in at an angle.



I think to myself, "self, why is this?". Turns out the aftermarket manifold had some extra material from the casting process!>! Tried to use a dremel with everything bolted up since it was a pain to get on there, but that wasn't enough. Pulled it all apart, grinded material away with the angle grinder, re-install. Everything bolts up EXCEPT, not my exhaust pipe won't bolt to the exhaust manifold!!!!. The old manifold had a flat flange, the new one has a ball looking joint coming out of it. Also, the exhaust flange spacing is to small compared to the flange on the pipe!! Are there differences in the manifold to exhaust pipe joint for a '74 CJ vs. post 1980?? I ask because on websites that seems to be the break-piont year for manifolds??



Now I need to figure out a new exhaust system maybe. Does it ever end???? All this for just wanting to replace intake gaskets, hahahaha



Scott



P.S. - Jeep 4.2l running on just the exhaust manifold are REALLY REALLY REALLY LOUD, even just at idle.



How bad is it to drive to an exhaust shop running just the manifold if I have to have a new one made up? Gonna burn up exhaust valves??

 

The "ball" on the end replaces the composition doughnut that was used on the earlier versions. Just put it together with the flared pipe end directly against the end of the manifold, no gasket.

If the stud spacing is wrong, then the manifold won't fit. I would send it back.

It'll be fine to drive to the muffler shop with open pipes, as long as you don't get a noise ticket.

I used a set of 1985 manifolds on my 1977 J-10. They bolt right up, except for some interference with the PS bracket.

 

Anyone have a bolt spacing measurement for their exhaust manifold I could compare to?

With my Jeep, who knows if the exhaust manifold or the exhaust system is at fault. Never can trust the PO.

 

yes you can, the valves will cool to fast and can warp.. DO NOT DO IT.. if you need to drive with no muffler I think the safe amount is at least 18 inches or exhuast pipe/tube.. this allows things to cool much slower. Also, just for fun, here is my exhaust flange buts also a header off a 96'.. no gasket, no bolts!! But i am guessing you can't do this on yours.

 

drive with just manifold but just as soon you turn off the engine stuff a shop towel in the exhaust manifold . it will not burn and let your engine cool slowly and save your valves

 

i guess that would work too, to idea is to just make sure they don't cool to fast.. and the "shop" towel is what i would use, flame re-tard-ent.

 

OK, all is well I guess. I was able to get the flange to finally bolt up. I had to clean up the threads on the manifold. That is why I was having such a hard time getting the bolts to thread which led me to believe the spacing was off.

Amazing what taking a 2 day break will do when you are trying to work frustrated....

 

So I took the Jeep out on Sunday to test out how quiet the new manifold was and make sure everything was working.

Everything was going well until I heard a rattle, then a boom. Then a constant ticking sound that I knew was an exhaust leak of sorts. I figured it was where the manifold and exhaust pipe join, but not so. One of the plugs in the exhaust manifold ports came out!!!!

Does anyone know what size plug I need so I can pick one up and put in there?

Thanks,
Scott