Heat riser and blocked intake manifold gasket

[Sammy]

Hi, 

read a lot , especially Jasons report of his work, about the blocked gaskets for use with the Edelbrock.

Before installation of Olsons gaskets,
yesterday I was at my mechanics garage and we looked at the heat riser.
The body as far as we can see it from the outside is intact, 
but the throttle is totally corroded, stuck and does hardly move. 

Does anyone have a picture to find out how the riser should look like when its completely open?
As the mechanic said it is risky to get the old one out without breaking the bolts
we thought about putting a weld spot on it when it is in the open position to stay there.

Thanks a lot,
Sammy

[Matti Roth]

Hi Sammy

in photo you see the throttle fully closed. The groove for the spring on top is 90 degrees rotated compared to throttle. I hope this helps!

[Sammy]

Thanks, for me it would be more helpful what it looks like when it is built in.

So where your thumb is the side that goes to the rear of the car?

[Matti Roth]

It does not really matter. From outside you see only the spring and the groove. When the groove is inline with exhaust pipe, the throttle is closed like in the photo above. When you turn it 90 degrees, it is fully open. Fully open in photo below. Of course we must expect that the throttle still rotates with axle and is not stuck closed. 

[Sammy]

I see, thanks. 

So it is possible that when turning the weight it might be to corroded and the 
inside will not turn with it?

[Jason Edge]

Sammy, Just stick a heat gun up to yours and see if it turns. If not it is stuck. this is almost 60 year old metal that has been blasted thousands of hours with corrosive exhaust gases. It is very common for them to stick.  If stuck or any doubt I would chunk it and buy a new one or at least remove the butterfly. Unless  you are driving the car in the sub-zero Arctic Tundra it is really not needed. If your car is all originally just and driving in really cold conditions just let it warm up a bit longer. Removing the butterfly will also reduce the hot exhaust gases going across the intake which causes the cracks.  You still get some bypass gas across the intake (unless blocked) even with the butterfly removed.

[Sammy]

We heated it up, but it is totally stuck. 
So we turned the outsight weight with a plier into a position we think should be "open". 
But the turning of the weight made me wondering if maybe the axle is detached from weight now and butterfly still stuck closed inside.

The mechanics are too anxious about taking it out completely so I'm trying to find another way.

[Matti Roth]

You should look the groove for the spring, That is located in the axle and not in the weight, so it shows how the axle and the butterfly are rotating.

[Jason Edge]

I would be anxious about leaving it in if it is stuck closed or partially closed. You can leave the pivot shift in place and just cut the butterfly part off.

[Sammy]

Yes I am, but if I don't find a mechanics shop to do that... 

Was it difficult to get it out?
Loosen both connections right and left I guess and do the bolts tend to break?

[Jason Edge]

You should have two  9/16"-24 nuts screwed onto the ends of the studs that hold the heat riser and tail pipe plate in place. Spray them with PB Blaster and let soak a while. If they have never been removed the stud can sometimes snap. Then it would be a matter of removing the exhaust manifold to get the stud out. Back to the 9/16" nut make sure you have good 6p socket on it. I use a 14 mm 6 pt socket  which is slightly smaller than than 9/16" but insures a super firm grip on the nut and you will not strip the nut.
Heat from a torch can also help back the stud out but be careful what you heat of. If they exhaust manifold to tail pipe flange nuts have ever been removed or replaced say in the last 20 years they usually back right off.

And just to add, those studs are double end threaded with a 9/16"-16 course thread where they screw into to exhausts manifold. Some people go back with course on both ends if replacing but I like the original setup with 9/16"-16 course at the exhaust manifold screw in side and 9/16"-24 fine on the outer end of stud.  Most Ace Hardware and some home improvement stores will have new replacements. If the studs are compromised I will put in a vice, heat up the hold studs with a vice, then back out with a monkey wrench and in stall new hardened studs. 

[Kim K Kaiser]

I took mine off.. during rebuild, I had it welded together.  it still worked after welding.  put it in, but it had a little rattle that was annoying, I finally just took it out and put in the spacer that I think Russ or Jason sell, I dont remember which,, but I live in MT and it has seemed to effect the warming up, that I can tell..  they are expensive to replace,, if you can find them,,