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#1 |
Registered User
Join Date: Aug 2006
Location: Redmond, WA
Posts: 6,332
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Heat riser spring and weight
Does anyone know offhand which direction these work?
Does the weight pull it open or hold it closed? Does the spring pull it open or hold it closed? I assume they work opposite each other and the spring is thermal, but I don't know which does which job. I'm trying, in the end, to figure out what happens when your heat riser gets old and maybe the spring gets weak. Does it fail to close or fail to open properly?
__________________
1970 GMC Sierra Grande Custom Camper - Built, not Bought 1969 Pontiac 2+2 427/390 4-speed Coupe 1969 Pontiac 2+2 427/390 4-speed Convertible |
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#2 |
20' Daredevil (Ret)
![]() Join Date: May 2003
Location: Jefferson State
Posts: 13,634
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Re: Heat riser spring and weight
The weight (and exhaust flow) opens it.
The spring holds it closed, when exhaust isn't forcing it open. I would say if the spring is weak, it won't close as fully as it should.
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- Mike - 1972 K20 LWB 350/350/205 RIP El Jay |
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#3 |
Senior Member
![]() Join Date: May 2010
Location: Wisconsin & Arizona
Posts: 4,844
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Re: Heat riser spring and weight
The weight pulls it open. The spring is a bi-metal spring that holds it closed until it heats up.
If yours is sticking so it doesn't open or close, you can buy a special lubricant and try that before buying a new heat riser. |
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#4 |
Registered User
Join Date: Aug 2006
Location: Redmond, WA
Posts: 6,332
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Re: Heat riser spring and weight
Thanks guys! Mine doesn't stick, it just stays somewhat closed and bounces around at hot idle, when I think it should be fully open. Not stuck though.
__________________
1970 GMC Sierra Grande Custom Camper - Built, not Bought 1969 Pontiac 2+2 427/390 4-speed Coupe 1969 Pontiac 2+2 427/390 4-speed Convertible |
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#5 |
Senior Member
![]() Join Date: May 2010
Location: Wisconsin & Arizona
Posts: 4,844
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Re: Heat riser spring and weight
This is the current GM version of the lubricant. Probably graphite based.
https://www.amazon.com/Genuine-Fluid.../dp/B00BK7MLKE |
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#6 |
Senior Member
![]() Join Date: May 2010
Location: Wisconsin & Arizona
Posts: 4,844
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Re: Heat riser spring and weight
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