Do I need a heat riser valve ?

[Lakewood90712]

I've got the headers removed, and stock rams horn manifolds ready to go back on, Intake side has with an Edelbrock manifold and non-stock Holly 4bbl.

Any need to put the heat riser valve back on ?

PS. I Put 1' pipe stubs on so hopefully nothing gets burned on the trip to the muffler shop, except maybe my ears..It's kind of LOUD....)
John.

[JimKshortstep4x4]

The heat riser valve, when closed forces exhaust gases to pass through the exhaust passege way in the intake manifold on a stock engine. The reason behind this is to warm up the carb faster and the intake manifold mounted choke.

We don't run heat riser valves on any of our vehicles even though we are in a colder climate and don't notice any adverse effects. Truck owners in colder climates then here could possible notice the effects of not running heat riser valves.

We run without them primarily because of the restriction on the exhaust flow and the frequent problems experienced with them as they tend to stick or rattle over time.

Jim

[vtblazer]

Originally Posted by JimKshortstep4x4

We don't run heat riser valves on any of our vehicles even though we are in a colder climate and don't notice any adverse effects. Truck owners in colder climates then here could possible notice the effects of not running heat riser valves.

heat riser valves are mostly a PITA over time/use.
I never run ther either but at times do notice it.

The biggest problem I run into not having one is during those "almost" freezing rainy/damp days when the carb wants to ice up.

I figure a decent comprimise would be to at least run a stove pipe to the air cleaner, that would give some warmer air.

[kaycee]

I noticed that the heat riser are chamferd to accept a donut to help seal for leaks.I have allways gutted the flapper and put a donut in and run it.How do you guys get the exhaust to seal ?My rams horn's are not chamferd on that side so I thought that they would not seal very good.

[Lakewood90712]

Thank's everyone for the input. The RH manifold I have has the chamfer, but it is not the original. Maybe it was from an engine with cable choke. Casting # RH12 3896956.Looks like I'm going to leave it off. 75 and older has no smog check in CA so it's good to go.

[vtblazer]

Found this surfing CK5

It's an adaptor made to replace the heat riser valve.

http://coloradok5.com/forums/showthread.php?t=162423

[JimKshortstep4x4]

Kaycee,

That is a good observation on the fitup of the doughnuts to the manifolds as they will leak without the chamfer.

We use an air grinder to hand grind the chamfer into the manifold using a doughnut to check the angle and fit. It is quick and easy to chamfer the manifolds which don't have the chamfer, and well worth doing.

Jim