Hello again C friends,
Here is the heat riser valve on the passenger side manifold of my 383HP factory dual exhaust. Thought I'd check to see if it was the cause of the hot condition, misdirected hot exhaust, fuel boiling, lame choke, and inevitable stall out.
I discovered this was stiff and not moving freely, so I sprayed the mechanisms liberally with pb blaster, moved it by hand back and forth until the counterweight was swinging nicely.. then dropped the exhaust pipe at the manifold to see the valve function.
The thermostat coil was still binding a bit so I sprayed that free and started her up. For some reason the valve did not open, or move in any way as the engine got (very)hot.. tired thermostat coil? Plus it was 90 degrees today here in New York.. but, I was able to temporarily prop and keep the valve/counterweight open with a wrench just to test. No (fuzzy)dice.. the engine issues I've been having persist.. and now I can say for certain that the same series of events/issues are happening in the same exact way over and over again:
Getting exceptionally hot exceptionally fast(but temp gauge showing normal).. fast racing idle at start up, which doesn't kick down automatically no matter how hot it gets. When I kick it down with a quick throttle burst at the carburetor once hot.. it idles lower and sounds good but still too fast.. and I have to do this manually. Then a few minutes later I'll just tap the throttle again, or put her in gear, and the rpms drop out completely, she struggles and then stalls. Auto choke on the carburetor/manifold not moving either, even when entire engine and intake are untouchably hot. Traintech was kind enough to be there again today assisting and assessing via phone and text videos I sent back to him. Not only is he very smart and generous of his time, but a lot of fun to talk with.. thanks again Bill!
So the carburetor remains suspect number one.
One other thing of note is when I ran the engine up to temperature with the exhaust pipe connected, and the heat riser valve open, the passenger side tailpipe out back was hardly warm... while the driver side was extremely hot.
I've noticed this for several months that the passenger side tailpipe is much quieter with much less pressure being pushed out than the driver side.
Blockage in the pipe or muffler? Even if so, it is now proven to be independent of the consistent, persistent issues up front.
I also checked with the exhaust pipe removed, and there is good pressure flowing from the manifold directly.
Also, every time I start the car she fires up with a singe key twist.. and the vacuum gauge I have connected to the manifold vacuum port reads a rock steady 23" hg everytime.
Another step closer!
*view looking up from under car*
