chief manifold nipple and rivet installion

[hairynob24]

G,day i want to rack some bodys brains . replacing manifold nipple , i read Cotten way to do it , but have to ask when drilling the hole for the rivet , should the hole be the size of the larger end of the rivet ? mine is 3.2mm to 3.5mm . I am at 3.2 at the moment . Should the the rivet fit the 3.5mm size than crush it down with the anvil tool and peen it from the out side , hope i explained myself properly , cheers Rob

[T. Cotten]

The tapered head of the rivet must be larger than the hole, of course, Rob!

You will want to lathe-cut the shank of the rivet to a light press-fit into whatever the hole cleans up at.

When twisted, an anvil should press the rivet outward from inside the nipple to wedge the tapered head into the hole for a a seal, and hold it firmly to be "upset" from the outside with a few simple smacks with a punch.

anvil.jpg

The shank should 'barrel' out to a tight fit within the casting, and the exposed portion 'mushroomed' only enough to appear like the original.

Here is a tapered-head rivet is compared to a button-head (HD) on top; Note how a button-head would need an extreme press to conform to the concave inside of a nipple, where a gentle taper would center and plug the hole.

RIVETRPR.jpg

Please remember that the nipple itself seals by butting its shoulder upon the casting, so it must be firmly seated, and sealed with something fuel and heat resistant. (Original JBWeld works well, if cured for weeks.) The Wigwam used a sealer on the threads as well, which might have been white lead.

NIPLSEAL.jpg

NPLSEAL2.jpg

.....Cotten
PS: Rivets are best cut from very large nails 'soaked' cherry red in hot coals, and retrieved in the morning

[hairynob24]

good man Cotten , this explains what i wanted to know , theres 3 of us all have a leak on the nipple in the same area , all 44s chief , not sure if this was a flaw or not , weird how all 3 are leaking , i can see the nipple wasnt seating properly in one small spot . I have made the tool you show , so now the rivet is the last piece , thanks for your info , Rob

[T. Cotten]

good man Cotten , this explains what i wanted to know , theres 3 of us all have a leak on the nipple in the same area , all 44s chief , not sure if this was a flaw or not , weird how all 3 are leaking , i can see the nipple wasn't seating properly in one small spot . I have made the tool you show , so now the rivet is the last piece , thanks for your info , Rob

Although I found way too many HD leaky nipples, Rob,..

The only Indian was a Sport Scout where too long of headbolts crushed them. Never has a Chief presented a nipple issue to me, although never did a '44 cross my benches.

If all three leak in the same spot, that's pretty damning, and I would inspect carefully to be certain that just a new nipple could cure it..

.....Cotten

[govmule84]

I do this entirely differently than Cotten does with a fair amount of success. Feel free to DM me if you want.

[Greasy rider]

I'm interested in how you do it, will you post here so everyone can learn something.
tom

[govmule84]

Sure. I'm gonna run you through my whole process, because the whole thing is different than a factory install. Full disclosure: First, I have done this on H-Ds, not Indians, but same theory. I just don't have many Indians to work on.

I got heavy into learning how to do this since a TON of Harleys have this leak problem. I sell my manifold pressure testers through a few retailers you likely shop at. I'm heavily invested in this because I make money at it, and I make no apologies about that. There are a lot of ways to fix leakers. This is mine.

Forewarning: you need a few out of the way items, a few chemicals you probably don't have, and running PEEK seals is mandatory. If any of that doesn't work for ya... then this doesn't work! Let's begin.

I like to have the jug (or head, in case of an H-D) off the bike. Remove the old nipple by crushing/chiseling it out... unscrewing is not preferred, since the hole for the rivet blows out the threads in the nipple. Clean the threads thoroughly.

I use a product by Gasoila called E-seal. I worked with them for quite a while to find a product that would perform in this application. It looks like this:



This product was designed for gas station fuel dispenser installers. It is truly fuel-proof, even with modern ethanol... I believe my oldest repair using this method is still hanging in five years later.

I coat both sets of threads liberally and install the nipple as tight as possible (within reason!) using an old manifold nut (and sometimes a spacer, if needed.)

After that, you've got to extract the nut. So I take an exhaust expander and pop it in. As you're tightening the expander nut, the plumber's nut has no choice but to pop off. Looks about like yay:



After that, you wanna get you a plug and some leak detection fluid (or soapy water) and make sure you're sealed up, of course.



Here's where I differ from the factory by a mile. I just ripped off a top end to get a nipple to seal. Why in God's name would I then drill a hole anywhere? And I'm supposed to be taking a hammer to an eighty-some-year-old cast iron jug (or head?) that costs a jillion bucks? Nah. Miss me with that.

We're going to be using PEEK seals, which seal up at a way lower torque than the factory brass stuff. In my estimation, rivets aren't even necessary: you're never gonna torque the plumbers nuts anywhere near as tight as you would if you were using brass.

But we still have the hole in the jug, and many folks want their bike to appear factory... so we have a solution. Pack each rivet hole in the jug with E-seal. After that, you build a little "cap" of black RTV silicone over the top of the E-seal and let it cure.

I'm not a huge fan of "goop" repairs, but this one has some things going for it. First, none of these have ever leaked on me. The E-seal is made to not harden, and so far it has not. Second, the leak from many of these is at the rivet. As the engine heats and cools, the rivet's hole enlarges, eventually letting air past. If you ain't got a rivet hole, you ain't got that spot to leak. Third, and I stress I have not had a single one of these go bad in five years...if it's going to leak, it will leak at the little E-seal/RTV plug you make for it. You can re-do that part of the job on the bike in about twenty minutes, even including picking out and cleaning the old mess. And if you ever decide this method sucks... it's pretty non-invasive, so nothing has been permanently deformed, not even your new nipples, so you can do it all over again a different way if you like with nothing damaged or modified.

Asked and answered. It's not the factory way of doing things.

It's a way that actually works.

[T. Cotten]

Obvious question, Gov,...

Why were rivets deemed necessary in the first place?

Its because threads like to get sticky after exposure to years of heat-cycles and the elements, much less any leakage past the ferrule seals. Then the nipples will want to back out with the nuts.,

Then you have to pull a jug to get it all apart, and then you will have to do it all over again.

(And if you still have the cores in those Schrader valves, sorry, but you are not applying a constant, regulated pressure differential, leaving your test open to false-negative results.)

....Cotten
PS: The green Gasoila must be totally different than the red, which didn't survive my P4gas immersion tests in the least!

[govmule84]

Then the nipples will want to back out with the nuts.

I think I addressed that: "We're going to be using PEEK seals, which seal up at a way lower torque than the factory brass stuff. In my estimation, rivets aren't even necessary: you're never gonna torque the plumbers nuts anywhere near as tight as you would if you were using brass."

There is zero reason to torque a plumber's nut on PEEK to the factory specs. So the "stickiness" of the nuts is a moot point, since you're dropping the torque spec by a ton. I agree with you if we were attempting this way with brass seals... it wouldn't work long term, if it even worked in the short term. My method cannot be utilized with OEM parts.

Won't work.

Then you have to pull a jug to get it all apart, and then you will have to do it all over again.

Nope. You won't. Because this way works. In fact, it works really well. Way better than smashing a rivet through an item you just tried desparately to seal. If the factory method was an effective one, you and I wouldn't have people purchasing our wares in an attempt to solve this problem, would we now?

The reality is we have access to better chemistry than the boys in Springfield and Milwaukee had. I choose to avail myself of it when it suits my purposes.

And if you still have the cores in those Schrader valves, sorry, but you are not applying a constant, regulated pressure differential, leaving your test open to false-negative results.

I think it does, friend. You can tell because... uh, all of the bubbles. And then the bikes start and run (much better!) after I repair them. Open-foot chucks and valve core removal tools are our friends.

The green Gasoila must be totally different than the red, which didn't survive my P4gas immersion tests in the least!

Passed all mine with flyin' carpets, to quote Ricky LaFleur.

[T. Cotten]

Let's agree we discuss this for everyone's benefit, Gov,..

And not everyone will choose or have access to proper PEEK seals; If a brass assembly doesn't show bubbles with a proper test, who can argue?

But if a nipple should ever loosen upon disassembly, you're screwed.

And I'm serious about a constant, regulated air supply. You can't just blast it with an air chuck because because it can never hold pressure: The gap between valve stem and guide alone is two orders of magnitude (perhaps jmore) larger than the holes we are looking for.

,,,Cotten

[govmule84]

Sure. Not everyone wants to use PEEK. I don't understand why as they're invisible for judging, but whatever. If PEEK is off the table, so is my fix. Que sera sera. I would never advocate pulling apart a motor that is sealed up by any method, but once the proverbial horse is outta the barn... you gotta deal with this somehow.

https://i.imgur.com/tRPfhqj.mp4

Clicky^

That's a Knuck, not a Chief, but the point is the same. Seems to be working there. Some bubbles are big, some are small. Just depends how bad the leak is. That's about eight pounds, probably more than any amount of vacuum a Knuck in good shape can pull. That's also a pretty bad effin' leak.

There are a bunch other tips beyond that. (Pressure test on the bench once the leak is repaired, for instance. Or leave the jugs [flattie] or heads [OHV] loose until the manifold is drawn tight, THEN go back and snug the jugs/heads.) However, this is the quick-'n'-dirty, Reader's Digest way I repair this leak. There's even a bit more to talk about on the different designs (Harley flattie has a wide, flat cast lip upon which the nipple must seal. Harley Knuck has a thin, cast narrow lip. Pans are a whole different material entirely!)

There are a lot of ways to skin a cat in this world, provided you enjoy the taste of cat.

[T. Cotten]

Some bubbles are big, some are small. Just depends how bad the leak is. ... ...

It doesn't matter how tiny the bubbles are Gov,..

MANBLSR3.jpg
MANBLSTR.jpg

manblstr3.jpg

MaNIBLSTR.jpg


They are still a leak.

It can take a half a minute to show themselves, so a chuck bump doesn't cut it.

...,Cotten
PS: Can anybody guess the vintage of those four Knuck manifolds?

But back to Chiefs..

POROSITY.jpg

[govmule84]

We are in agreement. Pressure (or vacuum) testing is the gold standard.

The constant, regulated air feed on my rig is producing bubbles. Some bubbles are big (like in the video) and some are small (like in your pictures).

In my experience, the size of the bubbles are usually closely related to the size of the air leak.

[Greasy rider]

Govmule84, thanx for posting and the discussion!
tom

[T. Cotten]

My exhaust pipe expanders won't fit a Chief, Gov!

In fact, they didn't fit anything very well, even exhaust pipes. So I adapted some scrounged collets:

nplcollets.jpg
(Note scrapings from a nipple cut by the larger one, showing how difficult it is to firmly tighten the nipple.)

With the variety of nipples, I needed a variety of 'anvils' as well, because rivets are prudent, if your reputation depends upon it.

NPLANVIL.jpg

As anyone can see, they ain't rocket surgery.

.....Cotten