Heat riser valve clocking

[John F.]

I believe my heat riser valve is clocked wrong. See two pictures attached. From underneath, I think I need to rotate CCW. Correct!

[John F.]

Re: Heat riser valve clocking

I got two nuts off and one stud all the way out. Now the header pipe doesn't want to come all the way past the studs. Surely , I don't need to disassemble one side of the exhaust system to get it to drop, do I? Or take off the right side manifold? Any easy ways?

I loosened the the clamp next to the cross-brace and gained a little wiggle room and pried down a bit. It is now off and soaking in Evaporust (my favorite rust remover). The riser was a little frozen up due to being installed wrong and not allowing it to work as it should.

[Wayne L.]

Re: Heat riser valve clocking

I removed the right side exhaust manifold when I had the same issue.

[Paul D.]

Re: Heat riser valve clocking

Exhaust pipe looks relatively new and rust free. Would removing RH pipe and muffler not be easier than manifold?

[Bob R.]

Re: Heat riser valve clocking

It's been a while since I last worked on that but I believe removing the bolts from the forward exhaust pipe and just pull it down below the manifold bolts. The exhaust system had enough movement in it to allow the removal and replacement of the heat riser. I might have loosened the center exhaust hanger a little also. I definitely didn't remove anything completely.

[Edward J.]

Re: Heat riser valve clocking

John, See if you can remove the studs on manifold first. then the heat riser can be rotated. take a couple of 3/8 nuts and lock them together and use the top nut with a open end wrench.

[Gene M.]

Re: Heat riser valve clocking

Correct flange, nuts and correct length studs would help your situation.

[John F.]

Re: Heat riser valve clocking

Thank you all for the advice. I got the frozen up heat riser off by loosening the clamp near the cross brace and a little prying and soaked it all day in Evaporust. See pics of results. I have new gaskets to pick up at O'Reilly's tomorrow.

[Brad Hillhouse (37766)]

Re: Heat riser valve clocking

John, it is fun and interesting to put a bolt in a vice and put that heat riser on the bolt and then hit it with a heat gun on high heat and then just no heat with fan to watch it operate and see how it reacts to cool, warm, hot exhaust hitting it in operation on the car.

Brad Hillhouse
#37766

[Paul D.]

Re: Heat riser valve clocking

Back in the late 70's and early 80's I worked in a Chevy dealership and GM offered "Heat riser valve lubricant" in a spray can. Every tech had a can on his bench, but used it primarily as a rust penetrant. It worked great! Chip.

[Patrick H.]

Re: Heat riser valve clocking

Back in the late 70's and early 80's I worked in a Chevy dealership and GM offered "Heat riser valve lubricant" in a spray can. Every tech had a can on his bench, but used it primarily as a rust penetrant. It worked great! Chip.

It's now GM 88862628 Rust Penetrant and Inhibitor

[John F.]

Re: Heat riser valve clocking

I ended up tying the valve open.

[Joe L.]

Re: Heat riser valve clocking

I ended up tying the valve open.

John------


That's the best approach. For non-judged cars, removing the valve and installing a spacer (as used for FI applications) works well.