Heat riser tube question - 29 Buick 116"

When replacing the heat riser tube, is there just a tube, or is there also supposed to be some kind of packing that seals up the tube on either end? Someone on a different site suggested that there should be packing and "collars" to install/locate the packing but I hadn't heard this before. I don't see any packing or collars around my existing heat riser tube, so am not sure what to think. Does anyone know?

John:

The heat riser tube is a pressed fit in the heat riser. There are no packing / collars fitted with the heat riser tube.

There are metal collars that fit in both ends of the cross-over pipe that runs from the heat riser to the valve between the exh. manifold and the exh. pipe,

Bill McLaughlin

Bill is right on.

The ends of the tube should be exactly the same length as the riser body. I used a piece of aluminized exhaust tubing for my 24 Buick when I replaced it during the national meet in MN. I didn't have a replacement part, so I found a Midas Muffler shop that cut a scrap piece to length with a tubing cutter that left the ends slightly beveled so it did not catch while being pressed in. We used lots of lube oil and carefully pressed it into the riser body while keeping it perfectly aligned so it would not catch on the internal cavity.

Thanks Bill & Mark - I misunderstood what the other guy said; he was in fact talking about the cross-over tube. But I now know that the collars/packing are missing on my car, so I bought a set of collars.

For the heat riser tube, I was fortunate to find a short piece of 1-3/8" OD tube in the scrap pile at work - we use various sizes of tubing for frames. I am not sure if 1-3/8" or 1-7/16" OD is what I need, but will try it. 1-7/16" would be much harder to find if I need it.

Muffler shops have expander machines that can make the in-between sizes. I recommend using aluminized exhaust tubing to minimize rust.