Intake manifold fitting / leaks

[eddiepanhead]

New to Knucks, assembling a 47 FL with an aftermarket manifold. Attempted to seal it up with brass seals and had massive leaks while pressure testing at connection to front cylinder. Ordered a set of PEEK seals, installed and now bot connections leak. Could use any and all advise........Have limited experience with plumber fittings especially on knucks
Thanks

[Jerry Wieland]

New to Knucks, assembling a 47 FL with an aftermarket manifold. Attempted to seal it up with brass seals and had massive leaks while pressure testing at connection to front cylinder. Ordered a set of PEEK seals, installed and now bot connections leak. Could use any and all advise........Have limited experience with plumber fittings especially on knucks
Thanks

Is the PEEK seal leaking or is the insert leaking in the head?

Jerry

[eddiepanhead]

I will try to explore that today. If the inserts are leaking, how it that fixed?

[T. Cotten]

I will try to explore that today. If the inserts are leaking, how it that fixed?

T'ain't easy, Eddie....

Please review http://virtualindian.org/11techleaktest.html

Commercial molded PEEK seals are often doomed for a few reasons:
First, they won't fit anything but a perfect manifold.
Second, they use brass dimensions, which behaves entirely differently from PEEK under pressure from the nut.
Third, the largest producer of nuts put them out with an internal bevel that might be anywhere from 58° to a whopping 64°!

Worn spigots must be lathe-dressed true, and seals cut to a squeeze-on fit, maximized within the nuts, and matched to the internal bevel.

....Cotten
PS: Two aftermarket BT manifolds have crossed my benches recently:
One unique aluminum production that would have been fine if it had started out with PEEK, and yet another V-TWIN Colony 'second'.

This one wasn't as oval'd on the spigots, but still blemished enough to need re-cut. Un-plated, with the flange un-finished, its just a core.

[otis71]

I’ve had success with a coating of JB Weld epoxy on the nipple to head mating surfaces, not so much on the threads because they’re not tapered threads. Usually the rivet leaks also because the hole is egged out. This requires reaming the hole until it’s round and turning an oversized rivet to fit.

[T. Cotten]

I’ve had success with a coating of JB Weld epoxy on the nipple to head mating surfaces, not so much on the threads because they’re not tapered threads. Usually the rivet leaks also because the hole is egged out. This requires reaming the hole until it’s round and turning an oversized rivet to fit.

Indeed, Otis,..

JBWeld has proven more reliable than the expensive Seal-Lock cited in the VI article decades ago.

Please beware it requires weeks to achieve a fully fuel-resistant cure.

It must be noted also that the seal between nipple and Knuck head casting is achieved by a very thin and delicate lip; Any damage at all is serious.

...Cotten