Board index Flathead Power-Technical Questions, Answers, and Suggestions Big Twin Flatties Enfield Racing Peek Seals

Enfield Racing Peek Seals

Post Sat May 16, 2009 8:05 am

Posts: 1676
Location: Interlaken, NY USA

Enfield Racing was mentioned in a thread on another topic. Just thought I'd pipe in on one of Bruce's products myself. I got a set of Peek seals for my Flathead 80 and the Knuck last year from Bruce at RhineBeck. Thoroughly enjoyed talking with him, he's one smart cookie. And I liked his attitude. Basically he got into making WR stuff so he could help keep the competition for his RE running! Anyway, the seals have worked out great, were reasonably priced, (thanks Bruce), and I'd recommend them to anyone. It was a totally new experience to not have to tighten my manifold nuts with my 18inch Crescent wrench for the first time. Just "Good and tight" did the job.

Post Sat May 30, 2009 8:14 am

Posts: 131
Location: BRANFORD, CT

Hi Dick,

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

Bruce Argetsinger
AHRMA Dirt Track # 67J

Post Sat May 30, 2009 11:10 am

Posts: 1676
Location: Interlaken, NY USA

Hi Bruce,
Your comments on torquing Peek vs brass seals mirrors my experience. I did the torque and test until I had a perfect seal. There's no way I can get a torque wrench in that confined space, but I'd say 20 Ft-lbs would be about right.
I'll be going to Rhinebeck again this year, will we see you there? I'll need another set of Peek seals for the chopper flathead motor as well.

Post Sat May 30, 2009 11:23 am
Pa Site Admin

Posts: 5843
Location: Ohio USA

Please keep us updated Bruce. I am another who is extremely interested in your test results. Thanks, Pa

Post Sun May 31, 2009 7:09 am

Posts: 3160
Location: Central Illinois, USA

I can only suggest one improvement:
Supply the manifold too!

Please let me take this chance to remind everyone that the wonderful ability of PEEK to conform and seal means that the nuts will seem to loosen with the first few heat cycles. Simple re-snugs at first, and then checks at regular maintenance intervals insure that the seals will be lifetime replacements.


Post Sun May 31, 2009 11:22 pm

Posts: 77
Location: Espoo, Finland

I can only second Cotten. Re-snuggin' is crucial. Otherwise totally problemfree.
I've had Cotten's PEEKs in my Indian about 6 years now, and they've never failed. (yes, Cotten was the first to cut these little buggers)
And they are re-useable

my 2 eurocents worth


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