I'm drilling and tapping the exhaust manifold for the pyro probe. Does anyone know the wall thickness? It's not critical, but will help me set the probe in the hole correctly. Thanks.

 

The printout from the TST site has some of those dimensions. IIRC its about 1/4 "....

 

Just insert the probe until it touches the manifold floor and pull it back out .187"

 

No, I mean the thickness of the cast iron. Not the size of the passage opening. I want to make sure I get the threaded portion of the probe even with the inner thickness of the manifold ... not down in the exhaust flow.

It seems to me that the probe's dimension past the threaded collar is set. Once I get the NPT threaded collar correctly positioned in the manifold, the probe screws into the collar. There's a rib on either the collar or probe that bottoms out. That should set the probe at the right position into the exhaust passage.

OK, well just looking on the TST instructions ... I'll just make sure that the probe sticks out of the collar between 0.3" and 0.7" (according to TST). I'll double check it at home and target 0.5" past the collar.

 

When you drill the hole, you'll be able to readily measure how thick the casting is...

EGT probes come in compression-nut & slip-fit flavors, difference is their adjustability.

 

Well, I was able to get a rough measurement ... about 1/4 inch thick. So then I marked the threads to be left at the top to know how far to screw in the probe. Worked good.

The probe has a couple ribs on it to serve as the bottom stop for the top nut. I threaded the collar into the manifold (using anti-sieze), then threaded the probe into the collar. The probe's compression nut threaded down until the ribs on the probe bottomed out. Job done.