'66 pass header valve rusted, what now?

[blink182house]

So I have an exhaust leak at the collector on the pass. header on my 66 calais, and I'm pretty positive after throwing it up on the lift and dropping the downpipe that its the butterfly valve's body/gasket. The issue though is that the studs from the oem manifold have taken a liking to that extremely rusted out valvebody... they have become one. So I guess I am looking at just replacing the manifolds eventually now? If I ever do get that body off i'm 100% sure the studs are going to break, and those oem manifolds sure arent going to be an easy task to drill/tap in that case. Any recommendations on experience with this issue? Thanks guys! Not a big problem, just trying to think ahead! I can't stand little leaks here and there!

[pdxmose]

Mine were pretty terible looking as well.  The threads were completely rusted off on the exposed part of the stud.  I broke one off on tear down.  I was able to remove it by welding a nut to the broken stud (which was below flush).   I used lots of heat on the manifold when removing the others. 

If your manifolds are not cracked, they are DEFINITELY worth repairing the studs if they break.

Look into gutting the heat riser as well.

             ...mose

[blink182house]

So you recommend cleaning up the exposed studs, welding nuts on them, heating up the manifolds and aiming for removal/replacement? Hehe... I already see this one becoming more than a 30min job hahahaha!

[pdxmose]

If it was me, I'd first soak the nuts in a penetrant like PB-Blaster for a week or so, then try to remove them with an impact as the hammering action won't twist off the studs.  If they come off, I'd try to get away with just puting new nuts on.  If the studs break, then you're comitted.  I think it would be difficult to heat or weld or drill in place, especially the drivers side.  Then you'd be pulling the manifold.  Which of course leads to this.......

[blink182house]

Well the NUTS aren't bad, I've actually removed them a few times. The gasket below the butterfly valve flange is replaced, but its the gasket above that flange that is blown. If i could get that flange off without breaking the studs in the manifold, I have no problem having a filler/spacer flange machined, but I'm certain its going to break the studs upon removal haha! Oh well, manifolds in the future...

So you can remove the exhaust manifolds without raising the cab?

[pdxmose]

That butterfly (heat riser) should fall off the studs without removing them.  But there's usually a lot of corrosion keeping it on there.  If you're going to toss the heat riser anyway, you don't have to worry about hitting it with a hammer to get it off.  But if you can get it off in one piece, just blow the guts out with a torch and plug the pivot holes and it makes a great spacer.

The manifolds have bolts, not studs, so I would think they would slide out pretty easy. 

         ...mose

[blink182house]

Hmm, my manifolds have 2 studs facing downward... and yeah corrosion LOL this thing is rusted INTO the studs. I've hit it with a 8lb sledge on a chisel and it aint budging lol, I'm afraid when it does those studs are snapped off! Working on a lift is a great advantage, but old age has set its foot down ha!

[The Tassie Devil (Bruce Reynolds)]

Never hit anything to do with a Cast Iron Exhaust Manifold with anything heavier than your hand.

Using a hammer is asking for breakages.

Bruce.

[Chris Conklin]

I'd be curious to see some pictures. You have studs from the cylinder heads for the exhaust manifolds? I'm gonna guess that they are at the ends where things are hard to access?

[pdxmose]

I think I confused everybody in the previous posts.  I was trying to answer the question of removing the manifolds in the car.

Manifold is held to head with BOLTS.  Heat riser and exhaust pipe flange is with STUDS. 


         ...mose

[Ronald]

When you go back together - run a die over the studs and then use brass exhaust nuts and double nut the studs.  Makes for a easier replacement in the future and prevents the threads from rusting away.

Ron

[The Tassie Devil (Bruce Reynolds)]

I am pretty sure that the original nuts would have been brass.

Bruce.

[EZ]

Take that stupid flapper valve out of there.  It's noisy and unless you live in Minnasota where's it's cold 6 months out of the year it's not needed.
I would also recommend blocking the exhaust passeges on the intake manifold so the exhaust doesn't go through there any more.  What a rust
trap and it also causes the intake manifold on the '65-'66 to crack if it gets too hot.  You can glue a piece of thin sheet metal over the opening with high temp RTV silicone to do the trick.

[blink182house]

Those images are the 'clean' version of my car. The valve no longer works, it stays open, and it doesnt create any noise so it's no issue there... the issue is that where it original 'slid over' the studs, it has now rusted INTO the studs literally. LOL I'm not having any issues with the studs having stripped threads or anything, the studs are fine PAST the flapper-valve.

I recommend if you drive your car regularly and this valve is still removable to go ahead and take it off and replace it with a spacer or shorter studs, because it literally will get to the point where it is nothing BUT rust!