67 327 heat riser operation

[John S.]

Should the heat riser valve be full open at idle with the car fully warmed up? Mine is closed until I start to give some gas then it opens.

[Joe L.]

Re: 67 327 heat riser operation

Should the heat riser valve be full open at idle with the car fully warmed up? Mine is closed until I start to give some gas then it opens.

John-----


The way you described it is the way they work. I've never seen one that fully opened at idle with the engine at operating temperature.

[John S.]

Re: 67 327 heat riser operation

Thanks Joe. I was just looking at the archives and found tons of stuff on this issue. Guess I will look there first next time. I think I am going to take Duke Williams advice and wire mine open and see if it takes care of the problems I have been having.

[Stuart F.]

Re: 67 327 heat riser operation

John;

It all depends on what problems you are having, but many cases, it is worth a try. However, I've been playing around with things on mine to overcome a severe fuel percolation problem. I have that solved, but in the process picked up several other minor issues incl. low speed lean surge and off idle stumble. I have limited both of those by removing my wire from the heat riser and going back to an automatic choke (from an electric). For what it is worth, I found that there is between 1.0" and 1.5" hg (vacuum) pull through the auto choke. When I use the electric, the heated air pulled through the choke is cut off and, of course, that has an effect on your mixture.

Stu Fox

[Joe L.]

Re: 67 327 heat riser operation

John;

It all depends on what problems you are having, but many cases, it is worth a try. However, I've been playing around with things on mine to overcome a severe fuel percolation problem. I have that solved, but in the process picked up several other minor issues incl. low speed lean surge and off idle stumble. I have limited both of those by removing my wire from the heat riser and going back to an automatic choke (from an electric). For what it is worth, I found that there is between 1.0" and 1.5" hg (vacuum) pull through the auto choke. When I use the electric, the heated air pulled through the choke is cut off and, of course, that has an effect on your mixture.

Stu Fox

Stu-----


1967 uses a completely different choke system than that used for 63-64. Wiring open the heat riser can slightly affect choke operation for a 1967, but, in most cases, the difference will be minor and not even noticed unless one operates the car in a very cold environment. No other choke-associated problems should occur for a 1967 if the heat riser is wired open.

[Stuart F.]

Re: 67 327 heat riser operation

Joe;

Thanks for the clarification. I guess the main point I wanted to make is that wiring open the heat riser is not necessarily a panacea (cure all). To make the example I used a little clearer, I should have said "the mixture" or "my mixture", recognizing there are so many different systems out there.

Stu Fox