I placed 2 slip joints in each of the header runners.  Can the slip joint
movement be maintained?  Can anything be applied to the slip joint to ensure
that it does not bind up?
Thanks for any help

Joe Berki
Limo EZ

The forces generated when a nest of snakes header system is welded up tight, like a street header for a V-8 where 4 headers are welded into a collector are immense. And so usually crack in a few years, and at very low temperatures. In racing that 4 into one header has pipes that slip into the collector and even though they fit snugly are not able to generate enough force to crack themselves.

 

I have Inconel headers from Indy cars built just like that. This allows the header pipes to be made so thin that they are discarded after 3 heat cycles. Probably not a good practice for airplanes.

 

If the slip joint is not so tight that it needs extensive hammering to get it together it will slip freely when it needs to. Another good reason to stay close to or below 1,600 degrees.

 

Put 3 feet of pipe in a vice. Place a dial indicator on the end of the pipe. Heat one side of the pipe and watch.

 

Like a hot exhaust pipe with air blowing on one side.

 

Inspect pipes before every flight.

 

I was cracking headers apart at the collector. (welded tight). I put a blast tube in to cool the collector.

The pipe cracked apart through the EGT probe hole.

 

I made a slip joint connection, and even with a Dutch clamp keeping the connection fairly snug, no cracks in 30 years.

 

Support the down stream stuff, so that the headers are not seeing any of that weight.

 

 

 

 

Lynn E. Hanover