Heat Riser Location Critical
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4th Gear
Joined: Mar 2024
Posts: 4
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From: New York
Heat Riser Location Critical
Hello all... upon checking my 72 Stingray 350 /auto trans/with A/C I found the heat riser valve on the driver's side exhaust and it seems to be functioning.
I know it has always been on the passenger side . Curious does it make a difference which side?Thx for any of your thoughts on this. JimD
I know it has always been on the passenger side . Curious does it make a difference which side?Thx for any of your thoughts on this. JimD
1967 Pedal Car Champion
Joined: Mar 2020
Posts: 9,062
Likes: 4,196
From: US-PNW
Hello all... upon checking my 72 Stingray 350 /auto trans/with A/C I found the heat riser valve on the driver's side exhaust and it seems to be functioning.
I know it has always been on the passenger side . Curious does it make a difference which side?Thx for any of your thoughts on this. JimD
I know it has always been on the passenger side . Curious does it make a difference which side?Thx for any of your thoughts on this. JimD
- Both down-pipes have flared ends to accept sintered ring gaskets.
- The driver exhaust manifold has a matching 45°ish chamfer for the ring gasket to seal the joint.
- The passenger exhaust manifold has a flat face that won't mate with the ring gasket.
- If you examine the heat riser, one face is flat, for a flat triangular gasket, and the other face has a 45° chamfer for the sintered ring gasket.
- Therefore, the heat riser won't seal well if placed on the driver manifold due to the mismatched gasket sealing surfaces nor will the passenger pipe seal well to the manifold for the same reason.
- Lastly, the down-pipes are different lengths to accommodate the presence or absence of the riser's 1.5" thickness. Unless the pipes have been modified over stock, they likely don't fit very well.
Pro
Joined: Nov 2023
Posts: 699
Likes: 335
From: Aubrey TX
It's all about exhaust gas sealing:
- Both down-pipes have flared ends to accept sintered ring gaskets.
- The driver exhaust manifold has a matching 45°ish chamfer for the ring gasket to seal the joint.
- The passenger exhaust manifold has a flat face that won't mate with the ring gasket.
- If you examine the heat riser, one face is flat, for a flat triangular gasket, and the other face has a 45° chamfer for the sintered ring gasket.
- Therefore, the heat riser won't seal well if placed on the driver manifold due to the mismatched gasket sealing surfaces nor will the passenger pipe seal well to the manifold for the same reason.
- Lastly, the down-pipes are different lengths to accommodate the presence or absence of the riser's 1.5" thickness. Unless the pipes have been modified over stock, they likely don't fit very well.
