Heat Riser
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Joined: Dec 2007
Posts: 74
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From: Edgewater Maryland
Heat Riser
I was wondering your opinion on wether or not to keep the heat riser on a 78 Pace Vette with a L-82 in it. I have added Edlebrock Alum Heads and intake. I also am in the process of installing the McJack headers. The Vette will reside in Fla. I have also changed the cam to a Comp grind that Johns Corvette Service recommended.
Melting Slicks
Joined: Oct 2006
Posts: 2,417
Likes: 336
From: Texas
i got rid of mine (79 L82) i considered it a flow restrictor. may help the engine warm up faster. but i didnt need it. the body of it is still in place used only as a spacer.,. because of the length of the exhaust pipe. i removed the shaft / butterfly, welded up the ends. I havent missed it at all.....
Drifting
Joined: Apr 2007
Posts: 1,970
Likes: 45
From: Cameron Park CA
I assume you mean the valve on the passenger exhaust manifold that closes when the engine is cold and forces exhaust gases through the intake to warm the incoming charge. With the headers, doesn't it go away?
I have aluminum L-98 heads with no exhaust crossover. Also aluminum intake. On cool mornings here in Northern California it's a bit cold blooded until the engine is well warmed up. As long as I don't give it too much gas too fast, it's fine. If i gas it too much it coughs and stumbles a second then gets going.
In Florida I don't think you will have a problem. We're enthusiasts, and a bit of nursing a car along until it's warm isn't a big deal, where your grandma or great uncle might not have the patience for it. Just my thoughts.
Pete
I have aluminum L-98 heads with no exhaust crossover. Also aluminum intake. On cool mornings here in Northern California it's a bit cold blooded until the engine is well warmed up. As long as I don't give it too much gas too fast, it's fine. If i gas it too much it coughs and stumbles a second then gets going.
In Florida I don't think you will have a problem. We're enthusiasts, and a bit of nursing a car along until it's warm isn't a big deal, where your grandma or great uncle might not have the patience for it. Just my thoughts.
Pete
Pro
Joined: Aug 2003
Posts: 530
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From: Victoria Texas
We made a custom one from stainless that is open, looks just like the stock exhaust flange pattern, It is going on a 67 big block with side pipes, we are useing the Mc Jacks headers also that replace the manifolds and hook to the factory side exhaust, had to have the spacer in there for the proper fit, just did not want a rusty cast iron block hooked to the nice looking headers, also had a custom set of free flowing side pipes built to let the 489 stroker breath.
one good advantage of having a full machine shop at our desposal.
one good advantage of having a full machine shop at our desposal.
Le Mans Master
Joined: Mar 2008
Posts: 5,948
Likes: 72
From: Oxford MA-----You just lost the game!!!!
When I was a kid, that part fell under the category "I don't know what it is, so get rid of it."
The aluminum intake manifold will allow heat to be transferred to the carb a little better, so I don't think you'll miss the exhaust cross-over, as long as you are using an electric choke.
Scott
The aluminum intake manifold will allow heat to be transferred to the carb a little better, so I don't think you'll miss the exhaust cross-over, as long as you are using an electric choke.
Scott
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Team Owner
Joined: Aug 1999
Posts: 30,995
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From: Ontario
Old Wives' Tale. Back in the day it was believed that it promoted rust-out of the right muffler owing to all exhaust heat being directed to the left side on start-up and a short period thereafter.
Drifting
Joined: Aug 2005
Posts: 1,443
Likes: 65
From: Wauconda IL
The valve is worthless if your motor has aftermarket heads (or intake) that has the heat crossover provision removed/blocked anyway-
I believe Corvette Central (among others) sells a replacement spacer that is open and fills the void left when removing the valve.
I believe Corvette Central (among others) sells a replacement spacer that is open and fills the void left when removing the valve.
Drifting
Joined: Mar 2011
Posts: 1,886
Likes: 9
IMHO, once you are using an aluminum manifold, you don't need the heat riser. The aluminum heats up much faster than cast iron. Besides, didn't we all just spend a bunch of money and time on a free flowing exhaust system? Why would we choke off one side of it?
Race Director
Joined: Jan 2007
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From: Danville Illinois
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Right/wrong, i tack welded mine open, manual choke
Advanced
Joined: Dec 2010
Posts: 79
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From: columbus ohio
You should go ahead and install Edelbrock heat insulator gasket. My hot starts improved dramatically after I did
http://www.edelblog.com/tech-tips/resolving-heat-soak/
http://www.edelblog.com/tech-tips/resolving-heat-soak/