Quote:
Originally Posted by eastbay
Not to be a Debbie Downer on this great thread, but that header contacting the oil cooler is a problem waiting to happen. You have options, but I would never run that setup as is.
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So I talked with William Knight and thought hard of all of the various options for modifying the right side header to allow for 1/4 inch clearance under oil return line on the oil cooler.
Given that I had just gotten custom fab work completed to connect the Knight headers to my muffler, I did not want to make changes that would move the collector from its current location. So I started thinking about heating up the #6 primary tube and deforming it from a circle to an ellipse to get the clearance I was looking for.
I did a little math to look at the cross sectional area of the current tube compared to the cross sectional area of the flattened tube (approximated by an ellipse so I could easily do the math).
The OD of my header primary tubes are 1.625 inch with 1/16 inch (.0625 in) side walls, so the ID of the primary tubes is 1.50 inch. The radius is then 0.75 inch, and the cross sectional area is pi x r^2 = 1.767 inch^2.
If I deform the circle into an ellipse with a minor axis (a) of 0.625 inch and a major axis (b) of 0.875 inch (I am squishing the diameter from 1.50 in to 1.25 inch to get 0.25 inch clearance, so the radius goes from 0.75 inch to 0.625 inch in the vertical axis (minor) and 0.875 inch in the horizontal axis (major)), the cross sectional area is pi x a x b which is 1.717 inch^2.
So heating up and pounding down the #6 primary tube to get 1/4 inch clearance under the oil cooler will reduce to the cross sectional area of the deformed regions by 2.77% and dyno data from the Engine Masters show on TV has shown that there are negligible effects to torque and HP, so I decided that was the corrective action I was going to take.
I bought a 3 ft section of 1/8 inch thick, 3 inch aluminum angle stock and fabricated a fixture to hold the primary tube head flanges to prevent them from moving out of alignment with each other.
I had clearly marked on the #6 primary tube the two areas that needed to be worked on.
I worked on one section at a time. Using a MAP gas torch I heated up the area to be deformed, then laid a piece of thick wall gas pipe on the heated area and struck the gas pipe with a single jack sledge hammer. I repeated the heating and pounding process until I had achieved the desired amount of deformation. Then I repeated the process on the second section.
I let the header and fixture cool back down to room temperature, then removed the fixture and reinstalled the right side header and reconnected the headers to the muffler.
I left the insulating wrap on the oil return line and verified that I now had 1/4 inch clearance between the #6 primary tube and the oil return line.
