I thought GM had done away with heat risers. Well, my '84 T/A has one & I will have to keep lubricated until, maybe next spring, when I can lift the car to remove the riser and then remove the butterflies.

 

The carbureted models had it. The fuel injected models just had a spacer. I had mine removed and now it functions as a spacer.
I don't know what kind of metal that valve is made of, but the guy who removed it for me had a hell of a time getting it out with a cutting torch. The holes were then welded shut...

 

I cut the shaft with a wizz wheel, took out the remains, and put 1/8" pipe plugs in the shaft holes.

Then I took a die grinder to the inner diameter, and enlarged it to the full size of the manifold and Y-pipe.

 

There used to be a specific heat riser lubricant. Standard Oil (now Amoco) used to have a line of "Atlas" products, so I don't know who actually made it, but it seemed to work well. Back in the day I used it liberally on NoPar engines since they seemed to need it the most. A few squirts, then forcing the weight against the spring back and forth a few times, then a few more squirts, and it would rattle like brand new again for months.

I believe it was very heavily augmented with graphite, copper, aluminum, and molybdenum, so when the carrier/penetrating oil burned off there was something remaining to act as a lubricant - A little like antiseize lubricants.

 

THe heat riser on my car, is vacuum activated.

 

Yes, we know...

 

Its only closed with cold eng starts. I cut mine out, cut the shaft/butterfly off, reinstalled the remaining piece, welded a washer to the stub inside. So it looked like all was there...on account of the smog man.

 

Next spring, I will remove the heat riser and cut out the butterflies and plug the vacuum line.

 

...And the pivot still sticks like any other heat riser. Just keep it well lubed with something suitable for the application until you can "mod" it out if you choose.

 

GM now only refers to the product's original purpose in small print.

 

I had a thick International truck exhaust donut that was the perfect replacement for my heat riser valve,got it a the flea market for a dollar,worked for years until i installed headers.