heat riser operation
Thread Starter
Burning Brakes
Joined: Aug 2000
Posts: 952
Likes: 0
From: Morgantown,WV USA
heat riser operation
I was hoping someone could help me with something on my 78 L48.
There seems to be vacuum to the heat riser all the time- when its warm and I disconnect the vacuum line the heat riser rod moves down and then back up when I reconnect the vacuum hose. I am thinking the TVS switch may need replaced.
Should there be vacuum to that heat riser after the car is warmed? When is the heat riser fully open- when the rod is up or down?
Thanks,
Dan
There seems to be vacuum to the heat riser all the time- when its warm and I disconnect the vacuum line the heat riser rod moves down and then back up when I reconnect the vacuum hose. I am thinking the TVS switch may need replaced.
Should there be vacuum to that heat riser after the car is warmed? When is the heat riser fully open- when the rod is up or down?
Thanks,
Dan
Burning Brakes
Joined: Dec 2005
Posts: 992
Likes: 56
From: Baldwinsville, NY
Yes, Rod down open and no vacuum rod should be down. Mine fell off during a head change and rolled under the car. Three years later an I still can not find that heat riser. I am using a spacer till I find it.
Team Owner
Joined: Jul 1999
Posts: 65,492
Likes: 230
From: Orange Park Florida
Yes, the only folks who maybe really seriously need that heat riser to close in winter, live in Minnesota/some such...
the one thing you need watch is that the crossover passage on your intake mani is open.....if you have really cold winters....
in fact, down south, and even in Maryland, I found that blocking that heat/exhaust crossover passage with plaster of paris was the best solution for carb overheating in the summer....but that means you have to change over to an electric choke....nothing manifold related....
the one thing you need watch is that the crossover passage on your intake mani is open.....if you have really cold winters....
in fact, down south, and even in Maryland, I found that blocking that heat/exhaust crossover passage with plaster of paris was the best solution for carb overheating in the summer....but that means you have to change over to an electric choke....nothing manifold related....
