Heat riser function?

I had some guy weld my exhaust manifold back together. I was pretty desperate, and he did it in short order, but I've got to go back and complain about some smaller things that aren't right. Before I do I'd like to know if I should complain that the heat riser shield over the exhaust ports, with the hose connecting to the aircleaner, wasn't put back on. The hose end is now just parked nearby the manifold. (Thats better than when I recieved it, with the hose sticking through the unfastened van engine cover into the passenger compartment.)

What benefits am I missing without the heat riser? Does it protect my spark plug wires? Will the slightly cooler air cost me a quarter mile per gallon? I'm frankly clueless.

Nils

Reply to
Nils K. Hammer
Loading thread data ...

The heat riser allows warm air to enter the air cleaner during warm up. This promotes better gas atomization and speeds up the warm up process. Chances are that you won't really notice much of a difference. If you're constantly making short trips, it may effect you more than not but once your engine has reached operating temperature, the heat from the heat riser is blocked by a vacuum motor and it's factored out of the equation.

-Bruce

Reply to
Bruce Chang

It helps the engine warm up quicker when it's cold; other than that it doesn't serve much of a function. Unless you're quite anal retentive about this vehicle I'd just leave it as is until you can find an uncracked manifold.

nate

Reply to
Nathan Nagel

That's not really a heat riser, although I understand what you mean. The hear riser is inside the exhaust pipe and restricts the flow of exhaust as the vehicle warms up. The early warmup air duct you speak of should be hooked up and that is easily done. Otherwise, cold running could be rough and economy suffers.

Reply to
WasteNotWantNot

You may experience; a slight loss in fuel economy a 'tip in' hesitation during intermediate warm-up carburetor icing during certain weather conditions failed equipment inspection during an emissions test

Reply to
Neil Nelson

MotorsForum website is not affiliated with any of the manufacturers or service providers discussed here. All logos and trade names are the property of their respective owners.