How do I tell if I have an exhaust leak?

[jkarolyi]

Hi All,

I've been enjoying my '71 911E Targa for the past few months. I look forward to reading this board everyday!

However, since I bought it, I've noticed a "tick-tick-tick-tick" noise that increases or decreases in line with the RPM speed. It is at the same volume at all RPMS, and sounds much like an engine needing a valve adjustment.

I've adjusted the valves twice now (once again to make sure), and the noise is still there. It doesn't really make the noise until it is warmed up (180 or so). It has Carrera tensioner updates, so I don't think those would be noisy. The car hesistates and sometimes backfires on throttle tip in, but I know the carbs need rebuilding so I chalked it up to that. It never backfires on decel...isn't that the telltale sign of an exhaust leak?

How can you tell if you have an exhaust leak? Any telltale signs? What else could it be?

[Thack]

If you have a single outlet exhaust you can take a thick rag and cover the exhaust pipe outlet, than listen for noise or possibly "feel" for a leak.
And I mean feel for hot air not put your hand on a exhaust joint.

Mike

[jkarolyi]

I thought about trying that, but the cooling fan pushes too much air around, so it's hard to tell. I suppose I will take it back to Precision Motion , they seem to know what they're doing.

That's true about metal expanding though...so it shouldn't be an exhaust leak.

[OldTee]

Put some soapy water in a spray bottle. Run it cold and spray where you think you may have a leak. Hit the slip joint at the crossover, the Cat, around the exhaust stacks. Wear glasses and take a bath after.