Smoke testing headers

I have read often that headers can be smoke tested for leaks. Is this possible with the headers still fitted (in my case to a 355) and, if so, how is it done?

 

You need a smoke machine that some automotive shops have. They stuff the smoke pipe up the car's pipe, block off other orifices and let the smoke reveal the leaks. It is possible to test your headers with them still on the car.

 

The testing is done with the headers installed (and cool)with an evaporative emission system tester.
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Yup, but what puzzles me is how to block off the other orifices!

 

Duct tape works just fine.

 

Like your style

 

There is a lot of info on the net about making a simple smoke machine at home. I think you would only have to block the air intake for this to work.

 

How do you get all the exhaust valves closed to the exhaust system at the same time?

 

Don't overthink this. Intake and exhaust valves are typically NOT open at the same time. You don't have to block the intakes. Just tape off the exhaust pipes and add the smoke. If there's a leak, you'll see it.

 

This is encouraging - I was, as you said, overthinking the procedure. I have always wondered how it was possible with the headers still fitted. Just do it, is the message I am getting. Thanks.

 

The independent shop that services my BMW has a smoke machine-- you just occlude the exhaust tip(s) with tape or whatever except for the tip the smoke machine is occluding then watch for smoke to appear at any holes or loose clamps in the exhaust system.