Sorry for the many questions. I am waiting on my book I purchased from the NCRS. The heat riser (I am learning)is between the exhaust manifold and exhaust pipe. The book I have now mentions it but that is all. the way it is on there now is exhaust manifold, heat riser?(chunk of metal),douhnut and exhaust pipe with bolts. Nothing moves and nothing else is there for vacuum etc. Am I in the right ball park or wrong stadium. Thanks
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Re: 65 heat riser
The "chunk of metal" should have an arm coming out one side that has a sort of rectangular end (counterweight). This ought to move freely, and when the car warms up should move 90 degrees to open the butterfly valve inside the heat riser. They are so troublesome (propensity to stick closed) that it is common practice to wire them open. The car will still warm up, just takes a few minuets longer. Best overall solution is to have one installed and properly functioning, but you need to keep an eye on them to be sure they are opening when they should. Early fuel injected cars did not use a heat riser and there is a spacer available for those cars that replaces the heat riser if you are so inclined. -
Re: 65 heat riser
Jimmy-----
There should be a "triangular" shaped, flat gasket between the manifold and the heat riser valve, then the valve itself with the counterweight oriented "rearward", then the donut gasket ("packing"), then the exhaust pipe, and then the exhaust pipe flange which secures the whole assembly.
There is no vacuum applied to the heat riser valve. That feature didn't begin until the late 70s with emissions controls of the period.In Appreciation of John HinckleyComment
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Re: 65 heat riser
I have taken off the ehaust and the heat riser has nothing in it looks like a giant spacer to me. I have this question is it necessary to have this or is it dependant on the climate.(I live in Oklahoma) I want it to be right without alot of hassles. thanks for the help.Comment
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Re: 65 heat riser
The function of the heat riser is to divert hot exhaust gas through a passage underneath the carb to help vaporize the gas when the engine is cold. As the engine warms, the heat riser thermostatic spring begins to open the valve and allow the gas to exit through the exhaust pipe on the heat riser side. If it isn't present, it will extend the engine's warm up time a little. If you only drive the car in moderate temperatures and above, it probably isn't an issue. If you are driving it in cold temperatures frequently,the extended warm up time could have an adverse effect on your engine, ie too much unburned fuel washing down the cylinder walls.Comment
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Re: 65 heat riser
It sounds like someone replaced the heat riser with the FI spacer. I did this on my '63 SHP engine, and it has no noticeable effect in mild weather conditons.
If the spacer is present or if the heat riser is wired open the exhaust flow out both tail pipes should feel equal when cold. With a proper functioning heat riser there is very little flow out the right side when the engine is first started. After a few minutes the heat riser should open, but it's common for them to stick closed.
Even if the heat riser functions properly it the RH muffler tends to rust out prematurely because of all the condensation that develops.
DukeComment
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