Thanks for the feedback on the seals.
I have just finished up some preliminary tests on how much torque it takes to seal PEEK seals as opposed to the standard brass, and thought people on this forum may be interested in the results.
A test fixture was built that I could pressurize using a standard nipple, which was welded to a plate, a nut, and a closed end tube the size of the manifold. The brass seals are from one of the major suppliers and the Indian Chief size was chosen because of the smaller cross section than the H-D thinking that the less material to compress would make it more prone to leaking.
Pressure was 20PSI and the nuts were torqued in 5 ft-lb increments until leaking stopped, final checks were done under water.
The PEEK seal had totally stopped leaking at 20 ft-lb, while the brass was still leaking slightly at 60 ft-lb.
Keep in mind that this is only a preliminary test on a extremely small sample and that I will be running more extensive tests in the future which will include heat cycles (sorry I don’t have a vibration test set up).
The most interesting thing I found was the difference of the “feel” between torquing the PEEK and brass. The brass was almost like hitting a brick wall once it was tightened. Increasing torque by 5 ft-lb resulted in almost no perceptible rotation of the nut. On the other hand the PEEK had a noticeable rotation of the nut between the 5 ft-lb increments. To me it felt similar to the torquing of a head bolt or connecting rod cap bolt as it reaches the proper torque or stretch. This is probably due to the compression of the PEEK as opposed to the brass, and the brass either sealing or leaking. Think of a paper gasket and a rubber one.
If people are interested I will post more results as I get them.
At this point I have several hundred seals out there and have only had comments from about 4 as to their success or failure.
Feedback is the only way I can improve a product.
You can email me directly at email@example.com