440 Exhaust Manifold Leak

[Charger_Dart]

I just can't seem to get my 440 passenger side exhaust manifold to seal to the head.    I have tried a few things -

1) Used plain Fel-Pro stock type gasket - leaked

2) Took the manifold to a machine shop and had it resurfaced - leaked

3) Tried composite gaskets (can't remember the brand) - leaked

4) Just tried Percy's 66036 gaskets and they leaked worse!

The leak seems to be where the long tube manifold nut attaches the manifold near cylinder 6. I took a couple pic's of the composite gasket I took off last night. Anybody have a good idea what to try next?

   

[JB400]

Are your bolts too long?  Are your bolts going in the head all the way?  Do you have enough threads on the bolt to where it screws in far enough?  Are the threads in the head clean?

[Charger_Dart]

Are your bolts too long?  Are your bolts going in the head all the way?  Do you have enough threads on the bolt to where it screws in far enough?  Are the threads in the head clean?

Thanks for the reply.
I am using studs with nuts instead of bolts to secure the manifold to the head. I added lock washers to all the nuts to see if that would make a difference, but it did not.
I even added a lock washer to the long tube type nuts just to make sure it was not bottoming out. All the studs are screwed into the head as far as they can go.

[Dino]

The dead soft gasket didn't work?  That's scary.  My headers leaked quite a bit and those fixed it.  

I would probably put a bead of rtv or something on the manifold and bolt it to the engine.  Let it set up and then take the manifold back off so you can see how thick the gasket is all around.  

[Charger_Dart]

The dead soft gasket didn't work?  That's scary.  My headers leaked quite a bit and those fixed it.  

I would probably put a bead of rtv or something on the manifold and bolt it to the engine.  Let it set up and then take the manifold back off so you can see how thick the gasket is all around.  

Yea, I ordered the dead soft gaskets after I read your post about them - oh well, wish they worked for me like they did for you!

[Mopar Nut]

I wonder if the head is warped.

[chargd72]

I wonder if the head is warped.

That was my thought.  Take a ruler edge to the head at the exhaust ports and see if you have any high/low points.

[Charger_Dart]

I wonder if the head is warped.

That would really suck - I will check it 

[tan top]

dont know if this is any help  ,  fitted repop cast iron manifolds to mine after the resto   ,  ( originals were cracked could of welded but thats another story  )
little while later decided to swap to  another set of heads , as i removed the passenger side manifold , saw black soot  2 thirds away across the gasket on number six exhaust port , plus a tiny worm track of carbon past that , had blown through past gasket   , all nuts were tight when removed hmmm  
the cast holes in the repop manifold are slightly off centre to the stud , or the originals are like that too     , also  in the exhaust manifold nut /stud kit i had  ,  one of the tube nuts was ever so slightly shorter that the originals  , never measured at the time  , but put them side by side ! all others were same , as oem  , just this one ,
never checked when first fitting , just assumed  
so the shoulder of the nut is rubbing manifold when final torquing !  , could of just used a suitable size flat washer first then tube nut , but decided to counter sink the hole in the manifold a little
so long story cut short what i'm trying to say  , check tube nut is not touching manifold the last turn or half turn when tightening the nut
took the manifold off year later  , while doing something else !, not a trace of carbon blowing past gasket , not sure if that was the cause but ,  been ok ever since

[bobs66440]

The Remflex gaskets are supposed to be the best for sealing. I haven't tried them, but I tried their exhaust flange gasket and they worked great where the others just blew out. They are really thick and soft and have a 50% crush. Worth a try  

http://performanceparts.com/part/Remflex/RF6002

I have always used the FelPro blue ones with Ultra Copper RTV on all mating surfaces and never had a leak.

[Charger_Dart]

Thanks TanTop, the head of the long nuts seems to stick out of the top about 1/4" or so when its tight and does not seem to be hitting the manifold. I double checked it tonight and it looks good.

The Remflex gaskets are supposed to be the best for sealing. I haven't tried them, but I tried their exhaust flange gasket and they worked great where the others just blew out. They are really thick and soft and have a 50% crush. Worth a try  

http://performanceparts.com/part/Remflex/RF6002

I have always used the FelPro blue ones with Ultra Copper RTV on all mating surfaces and never had a leak.

Good idea on these. I think I will give them a try!    

[bill440rt]

I'm running Remflex gaskets on my '69 with TTI headers. Had a pesky leak on the driver's side header. Leaks no more! 

[red69superbee]

run a long hand file over the manifold flange so you can see where its touching or not.I always file on these and headers to make sure theyre flat

[Charger RT]

throw away the gaskets and put the manifold on without a gasket. I never use gaskets with stock manifolds. But in 2000 when I put my charger together they were in the gasket kit and I said ok I'll put them on. By 2003 the passenger side leaked. I took it off threw out the gasket and it has been fine ever since. Drivers side went by 2005. Did same thing to it and its been fine ever since.
Tim

[Charger_Dart]

Found the source of the leak. The manifold is cracked near the long tube connection.

Off to search for a passenger side manifold. To make matters worse, I saw a nice set at the Mopar's at the Valley swap meet last weekend. 

[Nacho-RT74]

throw away the gaskets and put the manifold on without a gasket. I never use gaskets with stock manifolds.

MaMopar never used and in fact there is not a Mopar PN for them simply because they don't exist