Am having my carb rebuilt and discovered a ton of carbon upon removal. Just read the chassis manual and noticed that a sticking manifold control valve could cause it to run rich. Checked my valve and it is stuck in the closed position. Sprayed each side with penetrating oil but no luck. Anyone removed one of these before? I'm thinking if I do I should be able to spray it from the inside and hopefully get it unstuck. Anything I should be aware of before attempting to remove it? Thanks.

GM makes a product called "heat valve lubricant" and it works better than any other product I have used for freeing up the manifold vales
Living in Texas, i would also toy with the idea of cutting to valve right out of the housing,as it is primarily a cold weather part.

I've read that after soaking with the GM Lub that a tap with a hammer might help. It is cast iron so don't hit it too hard or you might break something. Another option is to remove the manifold.

It may be more work than you want but removing the exhaust manifold is not that bad and it's much easier to free up or remove the butterfly valve when the manifold is off the car.

If you plan to go this route, get the right parts. First make sure you have a new manifold gasket for contact to the head as well as the heat riser gasket. Replace the bolts with new ones while you're at it. I found correct bolts at my local Ace Hardware store.

Both gaskets can be found on eBay. As a matter of fact I have a heat riser gasket that I don't need...

If you remove the manifold, check the heat tube that goes to the carb as well while it's off the car.

You don't have to remove the exhaust manifold--on 65 the heat riser is a separate part unlike the 63 where it was built into the manifold. If I recall Buick did not use gaskets in the exhaust system. I agree with The Old Guy--don't need it in warm weather so if can't free it up cut the valve out.
John

Thanks very much for the advice. It is a separate part. Looks like I may be able to remove the two 3/4 nuts and, with any luck and a bit of room, pull the exhaust pipe back an inch or so to clear the bolts and then remove the valve section to work on it. If I can't free it up then I'll cut it out.

Appreciate the help.

Engines with no crossover pipe (straight 4 and 6-cyl's) don't have a heat riser. You really don't need one, either.

I suggest you cut the 'axle' off, and drill & tap for a pipe plug on each side. Drilling and tapping cast iron is easy. Pipe plugs fit flush and look very clean when it's finished.

We use this proceedure for replacing small freeze plugs, too. - Dave

I guess I am just lazy, but if it is stuck so badly that you can;t free it ,all you need to do is cut the "innards' out. The ends that are stuck will stay stuck, and noone can see that you have modified it.

Some time ago, someone was making a spacer to take the place of the valve assembly. Either that or you'll have to add an inch or so to the length of your exhaust pipe where it bolts on to the manifold. If you don't, the right side pipe will be pulled up into the frame.

Most any exhaust shop will have a donut that will take the place of the ball end of the vavle assembley so the pipe will bolt up and you'll have a washer to help center the pipe and act as a gasket.

Ed

If you take the heat riser out, why spend another $25 for a blank spacer, when you already have one in your hand?
Drill the pivot out, and tap for a pipe plug. There will be no exhaust leaks. (Or, spend $85 for a new heat riser valve.)

I found a company that makes heat riser valves for all kinds of cars:
http://www.hamiltonmanufacturing.ca/index.htm This company is in Hamilton, Ontario, Canada. Call them:
Telephone: (905) 545-4888
They may have either a new heat riser or a kit you can use to repair your original.