Heat Riser or Exhaust restrictor.
#1
Heat Riser or Exhaust restrictor.
I recently bought an '86 k5 with 305. In order to register in MD. one needs a "safety inspection". New to the area and didn't realize what all they inspected.
The station is telling me I need a valve that's in the y pipe right below the manifold. I'm assuming that this is the heat riser valve but I saw a post that suggested there may be something called an exahust restrictor.
I can find the heat riser to fit the same year truck but for a 350CID. I know that the 305 is built on the same block but does anybody know if the part is interchangeable?..The only place I've found it is LMC Trucking and they're over $300. Really don't want to play they shipping back and forth game if it doesn't fit.
Any help greatly appreciated.
The station is telling me I need a valve that's in the y pipe right below the manifold. I'm assuming that this is the heat riser valve but I saw a post that suggested there may be something called an exahust restrictor.
I can find the heat riser to fit the same year truck but for a 350CID. I know that the 305 is built on the same block but does anybody know if the part is interchangeable?..The only place I've found it is LMC Trucking and they're over $300. Really don't want to play they shipping back and forth game if it doesn't fit.
Any help greatly appreciated.
#2
RE: Heat Riser or Exhaust restrictor.
Should be the same exhaust manifolds and all. You should be good to go. I am surprised that they are requiring this though... Must be due to the age, even though it is 23 years old now.
#3
RE: Heat Riser or Exhaust restrictor.
Thanks for the input.
#4
RE: Heat Riser or Exhaust restrictor.
BTW Rocks has the same part for under $100. I was just gonna cut the shaft out of the old valve and weld the hole closed. It would at least "look" like the valve was there. But I guess for the price might as well put it in. Being as I appear to be stuck in the great white north now might as well have a truck that warms up quickly.
#5
RE: Heat Riser or Exhaust restrictor.
Did the 1986's come with a heat riser or vacuum operated EFE valve. I have an EFE valve on mine and safety wired it in the open position.
#6
RE: Heat Riser or Exhaust restrictor.
It actually is a vacuum operated EFE valve but from what I can gather it does the same thing.
As far as wiring it open when I got this one of the butterfly was separated from the shaft driven by the vacuum valve. So it didn't work anyway. If it was leaking so bad around that shaft I would have just removed the butterfly and reinstalled.
As far as wiring it open when I got this one of the butterfly was separated from the shaft driven by the vacuum valve. So it didn't work anyway. If it was leaking so bad around that shaft I would have just removed the butterfly and reinstalled.
#7
Finally put the new heat riser/ EFE valve in. That and resealing all the joints on the exhaust made a huge difference in how quick the engine got to operating temp. Pain in the "you know what" getting it in what the home-built, at least that's what it looks like, exhaust.
Sure feels like sealing the exhaust leaks, yes EVERY joint, and re-installing new gaskets at the start of the "Y" pipe gives it a little more at take-off.
Sure feels like sealing the exhaust leaks, yes EVERY joint, and re-installing new gaskets at the start of the "Y" pipe gives it a little more at take-off.
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rocknroadie
1st Generation S-series (1983-1994) Tech
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09-02-2010 07:19 PM