Manifold valve thermostat

[capthook505]

Hi all I just removed the exhaust from a 65 Riv 401 and the manifold valve thermostat(manifold heat control valve, it has 2 names in the manual) that comes off the passenger side header is missing a spring or two and the one that is there seems to have a broken tab. My question is what do I do with it? Does anyone make this part or the springs? Any help would be appreciated. Thanks, Russ.

[alex bonino]

There is a lot of information in the form of previous threads on this topic. Try a search for "heat riser" or maybe "manifold heat riser".

Replacement heat riser valves pop up on ebay every now and then.

alex

[Guest musclecarfan65]

i have replaced the old iron headers with sanderson headers and my 401 riviera NH runs very smooth ... although the valve/riser is not there anymore. switching to different headers (sanderson or TA performance) could be also an option if you intend to finally eliminate the valve.

[RivNut]

Russ

Some of your question can be answered yourself by telling yourself what times during the year and how often will you be driving your car. The valve closes and forces heat up into the intake manifold to the base of the carb to help warm it for cold weather driving. If you're only going to drive your car in the spring, summer, and fall, and don't mind a little hesitation on cold starts, you won't miss the heat riser valve. Just wire it open so it doesn't interfere with regular exhaust scavenging.

The more you force that heated air toward the carb, the more of a chance you have of the base of the carb corroding from the exhaust. That's why the stainless gasket is sandwiched between the carb and the fiber gasket - to prevent corrosion. The performance nailhead guys plug the holes in the heads that allow those gases to reach the carb. You have to think of who bought this car in 1965 and what their expectattions were for a daily driver; yours might not be the same.

Ed

[capthook505]

Thanks for the reply, all. I was thinking of doing that Ed, just to wire it open. The car will mostly be driven in the warmer weather, and I'm not looking to go crazy here on the city streets anyway.

Russ.