Intake nipple

[rex]

I just discovered the dreaded and much discussed loose intake nipple on my 45. I understand that there are different fixes for different kinds of loose. My rivet is tight in the cylinder, but the nipple moves @ 1/32" in both directions.
Should I drill out the rivet, buy a new nipple and start over?

[Cotten]

'Fraid so,

Good luck, and let us know how it goes!

....Cotten

[rex]

1. Both intake nipples and rivets replaced using Seal Lock Fluid Weld.
2. Pressure tested to find leaks.
3. Applied vacuum to intake manifold, thinned Indian Head Gasket Sealer with acetone and painted all junctions between manifold and cylinder.
4. Continued painting while acetone flashed off and sealant returned to it's more viscous state.

My theory was that the initial low viscosity application of the sealant would coat the leaking surfaces, and as the viscosity increased it would slowly build up and close the leak.
So far it looks like it worked. After starting, the choke can be opened much sooner than before. Idle is smooth, and the Color Tune glass topped spark plug is showing a nice blue flame.
Just received my non contact IR thermometer today and will check cylinder head temps. on next run.
Since the gasket sealant isn't fuel proof, I'll consider pressure testing the manifold a regular maintenance procedure.

[Panacea]

Rex, how much pressure would you test with? mine leaks badly with low pressure around the steel inserts ( converted to o-ring manifold). do you think your vacume idea using gasket sealer would work better with green locktite? Somthing pliable might not crack and leak, but what? How about Gasoila? MW

[rex]

panacea-

Since this is a first time experiment, I used materials that I'm familiar with. A few test batches of the gasket shellac and acetone showed me that it could change viscosity and return to it's original state. Also, if it failed, it could all be cleaned off for the next trial.
I do have green locktite, but I don't know what to use as a reducer for it. It smells like it's in the cyanoacrylate family. I also am not familiar with it's fuel resistance or temperature range. I've only used it for metal to metal press fits.
If you're considering using green locktite in conjunction with o-rings, make sure the locktite won't melt the ring! I've got a bad feeling about that combo.
Pressure for manifold testing is @ 5-10 psi. Too much pressure will blow the soapy water away from the leaks and you won't be able to see exactly where they are.
As you seal the leaks and the remaining ones because smaller, very low pressure, a strong light, a mirror and straight water can show you with pinpoint accuracy where the leak is.
With the plumber nut manifold, you can see if a leak is from the nut/nipple junction or the cylinder/nipple junction. In assembly these junctions are so close it's hard to tell where the leak is in a sea of bubbles.
I've never used gasoilia, but have heard about it in the antique auto and tractor worlds.
As far as the Indian Head's pliability, my test batches were mixed in 2x6 aluminum foil baking pans which were evenly coated with the mixture. The next day the aluminum foil could be bent and crumpled without the shellac coming off.
Feel free to try any goop you want. Apparently all commercially available sealants can't stand up to the additives in auto gas for the long term. Even though this assembly operates under vacuum and isn't trying to stop the flow of liquid fuel from inside to out, during priming to start the engine, the bottom side of the carb-manifold-nipple-cylinder cluster does get wet.
If you're going to depend on a chemical solution to these leaks, test them regularly.
The best souce of info. for these issues is at virtualindian.com. Tom's the one who alerted me to the dangers of these air leaks that not only cause the frustration of fouled plugs and quirky idles, but also burnt pistons, warped heads, bent rods, etc.$$$$$$$$$$$$$$$

Rex

[Panacea]

Thanks Rex, my next sealer may be yammabond, it seems to be pliable enough to expand and contract with the heat cycles. We shall see! Mike

[Cotten]

The test for any sealer is a extended soak in modern P4gas.
Some sealers wrinkle in 15 minutes. "Saccharin" Loctites won't last the night. I had Caswell's epoxy last six months, but then flake off like skin on a dried date.
I recently scrounged a florist's flowerbud fixture made of lab flasks super-glued together. After an afternoon in P4gas, the cyanoacrylate ester was softening. I figure a few weeks before they fall apart and become usefull.
Once again, the problem is not finding quality sealers...there are many.
The problem is that modern fuel additives (associated with ethanol blends) are digestive enough to eat even powdercoating, and dramatically swell Buna-N and Viton, thus altering their properties and limiting their lifespan.
It may only be a matter of time until these formulas are promoted beyond the Midwest and Left Coast, if not already
A 'gas-resistant' claim on a sealer or paint label means nothing anymore.
And it is downright scary that the petroleum companies (specifically Shell) boast of such anti-deposit additives without ever naming them. (Maybe someone with better web skills can find something more discriptive than "additive", "detergent", or "injector cleaner".)
Why it is associated with ethanol is another part of the mystery, as ethanol itself will not deteriorate most sealers.
I wear rubber gloves a lot now. But I can't stop breathing. How much of this "detergent" hangs in urban smog?

....Cotten

[rex]

Saturday's test run resulted in cylinder head temps. in the mid 280s. Intake nipple/manifold junction @ 266.
I'm on the trail of a sealant used in aircraft fuel tanks. People I've talked to that have used it seem to think there isn't a solvent that can affect it.
When I find out more I'll start a new thread concerning it.
Now I'll move on to tryng to solve my speedometer mystery. (New Thread)

Rex