The Stovebolt Site Forums The Shop Area Engine Shop Exhaust manifold heat valve

I'm just finishing up my GMC 228 rebuild and separated the intake and exhaust manifolds the other night. I considered not doing this because the bolts were stuck tight and I was stripping them out trying to get them off. Now I'm glad I did it. When I got the two manifolds apart I found that the heat valve was cracked and looks like it's been welded at one time. What's involved with getting this repaired? The shaft doesn't rotate. Are parts available or is this a junkyard kind of thing? Thanks, Neil

Only new part I've been able to track down is the spring. They are usually a bear to get free. Usually heat and penetrating oil and time. Don't try turning the counterweight with pliers, there's a rivet through it that will shear off. Tapping the end of the shaft sometimes works. You can end up drilling out the rivets that hold the valve to the shaft to clean things up. Did I mention that it's not easy?

....rivets that hold the valve to the shaft..?

The only ones I've seen have the valve welded to the shaft.

If you grind the weld smooth with a die grinder then you can tap the shaft out and clean it. Start by tapping back and forth to loosen it up. Make sure you note the position of the valve so you can weld it back right. Digital photos work great.

I've used penetrating oil along with heat- a propant torch. When the mani is hot, gradually turn the shaft and try to wiggle it loose. Mine loosened up eventually. BTW, after buying a new spring, I decided not to use it since it never seemed to open up completely. I'm in So Cal though, so very cold weather is not a problem here.

The way I got mine loose was to drive the weighted casting left and right on the shaft. Don't bother trying to hit it opened and closed, It didn't work on mine. Just oil getting it to move further onto the shaft then back it off again. Scott

Cletis, every one that I've had apart has had rivets. Go figure.