10-07-2015, 10:23 PM
Join Date: Aug 2007
Location: Houston, TX
Total Cats: 117
Originally Posted by aidandj
Built this manifold last winter. I have something like 15k on it, and 8 track days.
Just found this crack. Ran it for a whole track day, and an 800 mile trip home with no soot coming out at all. Must not leak much. I believe it is from thermal expansion.
Drill out both ends of the crack to stop propagation.
Clean the inside very well and try and clean the actual crack (how?)
Backpurge and weld the crack.
Add a gusset between the 2.
Suggestions? What thickness plate should I use as a gusset.
Also thinking about cutting more relief cuts.
I think that broke from thermal stress on that joint. So solution is to spread the stress out (such as a gusset) or reduce the stress (cut flange between runners to allow them to move thus less stress)
Here's what I would do to fix it.
Clean, grind out, drill to stop crack.
Reweld. Then weld a gusset top and bottom to help spread the load out in that area. Then cut the flange to allow it to stretch a bit.
For gusset thickness, I would use 1/8" or so.