'48 FL Panhead - inlet manifold rivet question

[harleygreg]

Hi Guys - the intake nipple locknut (27048-52, see images) was missing on the front head and the screw part of the lockscrew (27049-52) was broken off - see photo. I want to replace these on the front and back cylinders but I don't want to replace the inlet nipples as this seems to be a problematic process, with a good chance of messing up the threads? It seems that these lockscrews and nuts were used to 'lock' the nipples in place, and it appears that they are inserted from the inside of the manifold?

Does anyone know how you refit the spares kit shown, and, as these are prone to leaking, what sealant one should use?

I'm assuming you remove the large packing nut, the bushing, and does the manifold then come out? If so, you would then fit the nipple from the inside, with sealant, and then fit a new packing nut and bushing on the old nipple? I'm supposing I would have to remove the heads to do all this?

Also, what is the purpose of part 27046-48 inlet nipple rivet?

Thanks

GregIMG_1281.JPGIMG_1282.JPGIMG_1283.JPGC2230-6.jpg

[T. Cotten]

Greg!

The nutted rivet was a "better idea" that didn't work as well as the original design.

Sealing them isn't easy.
I would suggest tapering the head of the replacement rivet, and some sort of compliant seal under the nut,.. if you had a '52.

If your nipples are otherwise sealed, I suggest replacing them with conventional rivets, with tapered heads and precisely fit to reamed holes.
(I annealed large nails, and lathe-cut them to size. Some tooling for setting rivets is discussed at http://virtualindian.org/11techleaktest.html)

Goobers will always be subject to digestive fuels.
JBWeld worked for years, but *something* changed, and now it must be cured many weeks to survive my immersion testing.
"Alkali silicate of soda" muffler and tailpipe sealer proved inert in fuels. (I tested "Bondo" brand.)

With the gland nuts backed off of the inlet nipples, the assembly can be coaxed out, with the brass seals still upon the manifold spigots.
The nuts are re-useable of course, but the brasses are not so friendly. New ones may not even fit the spigots.

Patience, and good luck!'

....Cotten

[harleygreg]

Mmmmmn! Interesting

[Architect]

Mmmmmn! Interesting

You have a gotten a response from the expert, seriously. Cotten helped me two years ago with a leaking nipple on my WL, his guidance made that project happen. Not easy at all, patience is the word. And listen to him.

PS: Hey Tom, hope all is well in your world, Bill.

[harleygreg]

So, I have removed the manifold and the two screws 27059-52, one was 1/4" and the other 3/16". The repair set is 1/4" too, so will drill the smaller hole out to just over 1/4" and hope I can fit the new part. Do you think this is enough or should I ream the hole to be accurate?

The favoured sealant on the net seems to be Fluid Weld, but I have also seen mentioned; Permatex Ultra Copper, JB Weld, Loctite grey hi temp - any ideas on which one to use, or other recommendations?

Thanks, Greg

[T. Cotten]

So, I have removed the manifold and the two screws 27059-52, one was 1/4" and the other 3/16". The repair set is 1/4" too, so will drill the smaller hole out to just over 1/4" and hope I can fit the new part. Do you think this is enough or should I ream the hole to be accurate?

The favoured sealant on the net seems to be Fluid Weld, but I have also seen mentioned; Permatex Ultra Copper, JB Weld, Loctite grey hi temp - any ideas on which one to use, or other recommendations?

Thanks, Greg

Greg!

Please note the date of the VI article,..
Fluid-Weld is unsurpassed for valve seat and guide replacement (as well as for "stitching" procedures), but turned out to not be suited well to filling larger voids, especially on tortured Panheads with no sealing lip.

The fit of the new rivet to a clean hole is critical to sealing with only a simple "upset" of a square smack or two.
Undo peening is to be avoided if possible, as its ugly, and shouldn't be necessary.
We do not have the massive press equipment of the factories, but with a tapered rivet head, and due diligence, it the cam-action anvil really works out well.
(The convex upset of early Pan rivets is harder to replicate than simple Flatty or Knuck rivets.)

I have no evidence that HD used a sealer, although I do that Indian used something like 'white lead'.
It is always best to depend upon a mechanical seal, with a sealer only as 'suspenders with a belt', because goobers are fickle in modern fuels.

....Cotten

[harleygreg]

Thanks for this Tom, but I have a few queries.

When you refer to the rivet, you are referring to 'conventional' rivets, which would be put in from the outside, and then the inside end would be 'upset', to create the seal, without the need for sealant. As the head is aluminium, rivets of the same material would be easier to use? I've seen on the web, tools made out of G-clamps to do the 'upsetting'? Is this an acceptable method in your opinion or are there better ways for a home mechanic to go?

Given the above, I assume that the spare part kit, which has the threaded rivet and nut, is not preferred, even though that was the chosen method at the time? As the bike will be judged by the AMCA, in the future, do you think the conventional rivet method would be frowned upon?

Sorry to labour this, and thanks for your input

Greg

[1950Panhead]

and then the inside end would be 'upset', to create the seal

The seal is between the rivet shank and hole.
If you ream the hole to .001" smaller then the rivet you get a good mechanical seal between rivet and hole which is better then any sealer.
Back to Cotten ...

[T. Cotten]

The seal is between the rivet shank and hole.
If you ream the hole to .001" smaller then the rivet you get a good mechanical seal between rivet and hole which is better then any sealer.
Back to Cotten ...

Ideally yes, 1950Panhead!

But there is no shank seal possible with a nutted assembly. It would stretch smaller, not bulge.
(I cut PEEK for nutted rivet seals, but with limited success if it leaks up the slot. Thus tapering the head is the only option for those vintages. The '48 style of rivet is actually easier to seal.)

Greg!

Upsetting the exposed, outside portion with a simple, direct smack should barrel out the shank of a conventional rivet, assuming a sweet fit, and a decent anvil holds it firmly inside.
Every little bit helps, particularly to avoid spitting the casting around the nipple by over-peening; Original rivets were button-heads (top in attachment) that just do not mate well with the curved nipple without a bodacious press, but lathe-turning it conical allows it to bite into the nipple for the first point of seal, and then the shank should do the rest.

The anvil can be quite primitive as long as it can be twisted to force the rivet outward for the upset.
I prefer ones that can be held in a vise, and the head twisted upon it, leaving a hands free for the mallet and punch.
The anvils shown here are turned with a wrench, allowing them to be used upon an installed cylinderhead.

....Cotten
PS: Finesse with a hammer helps, but here it depends upon simple and square. Knucks and Flattys are easier to replicate.
Early Pans with the die-pressed upset upset me.