Author Topic: Exhaust Riser Valve  (Read 1317 times)

Offline 85max

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Exhaust Riser Valve
« on: July 13, 2021, 12:27:15 PM »
Sorry if this is the wrong place but it's as close to the exhaust as I could find.  I have an 85 GMC with a 454 that has the Exhaust riser valve in the driver's side manifold.  Has anyone taken one of these off?  By the looks of the 84 manual on here, it seems that the valve slides over the studs from the manifold and the donut from the exhaust pipe kind of holds the whole thing together.

Offline bd

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Re: Exhaust Riser Valve
« Reply #1 on: July 13, 2021, 12:40:01 PM »
The valve, doughnut, and flange are retained by three nuts and spring pressure.  From the factory, the valve is a metal-to-metal fit with the manifold although gaskets are available through the aftermarket.  Saturate the three retaining nuts and studs with PB Blaster repeatedly over several days to a week prior to attempting to loosen the nuts or they will assuredly seize.
Rich
It's difficult to know just how much you don't know until you know it.
In other words... if people learn by making mistakes, by now I should know just about everything!!!
87 R10 Silverado Fleetside 355 MPFI 700R4 3.42 Locker (aka Rusty, aka Mater)

Offline 85max

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Re: Exhaust Riser Valve
« Reply #2 on: July 17, 2021, 01:55:02 PM »
Thank you.  I 've had the nuts off and replaced the donut, but there is a leak above the valve to the exhaust manifold.  On mine it looks like there are collars on the studs which hold the valve to the manifold.  Maybe they will slip off over them, I don't know.  Just wondered if anyone had taken this whole thing off before.