Manifold Inserts

[Bill Pedalino]

I'm sure that this is a thread that T. Cotten will respond to - he is the expert, but ALL responses are appreciated.

I have replaced the manifold inserts in my '47 FL, but am having trouble installing the rivets. After peaning the ends, they flatten out and I can't get the rounded look on the peaned head that is proper for a tight fit.

I bought a bucking bar, but can't find the tool with the proper concave rounded tip for forming the head.

Also, should the rivet be heated cherry-red before peaning so when it cools it shrinks and tightens - or will this crack the cast Iron head casting?

Does anyone know where to acquire the correct rivets and tooling?

Thanks,
Bill Pedalino

[T. Cotten]

Bill!

Sorry I'm late.

I have included some observations and pictures of my tooling for such
procedures at http://virtualindian.org/11techleaktest.html

Please inspect first the mating surfaces of the back of the nipple and the
counterbore/lip of the head casting. This is the difficult interface; if there is any damage to the lip at all, sealing is quite difficult..

It is prudent to install in two stages. The new nipple (with parkerizing removed by blasting!) can be re-installed with a fuelproof locking sealer using a greased nut and spent ferrule, if allowed to cure before the nut is removed. A pressuretest at this point may prevent a wasted rivet installation, if problems persist.
The nipple can then be drilled and reamed for fitting for a minimally
oversized rivet, with a flared or tapered head (instead of a flat-bottomed
one that does not conform to the concave inner surface of the nipple).
With a simple cam-action anvil inserted within the nipple to push the rivet
outward, minimal peening is necessary to achieve a seal, and your casting is
best protected against the blow.
The rivet may be made overlength, as the excess can be trimmed after it has
been pressed outward, before it is upset with the ballpeen and drift.. After
the rivet's sealer has cured, another pressuretest will determine your
success.

I consider nipple replacement to be as difficult as any operation in all of
vintage motorcycle restoration. You are very much at the mercy of your own
observations, cleanliness, attention to detail, and resourcefulness at
making tools. Please let us know any questions that arise as you attempt it.


...Cotten

[Tommo]

I agree with Cotton right up until you drill the hole for the rivet and this is where I use a different procedure.
Before installing the nipple I tap the rivet hole 3/16 unc and then proceed as Cotton describes. Once the nipple is in I spot drill an indentation in the nipple through the rivet hole and then screw in an unbrako grub screw that has been coated with hi-temp Loctite. Then you make yourself a dummy rivet head that you tap in over the grub screw and the jobs done.
When I first started doing it this way I always used to put a small centre mark in the head of my dummy rivet in case I ever had to drill it out but as this has never been necessary all the ones I have done of late have had the centre mark left off.
I defy anybody to look at it and see that it appears anything but factory.
If the rivet hole is too large to accept a good 3/16 unc thread you just need to go to the next best size for the job and yes that may be a metric thread form but who will know, only you and I won't tell if you don't.
I prefer doing it this way as you eliminate at least one area that could leak and you also eliminate that rivet head in the induction passage and before you all say brilliant, it was not my idea, it was told to me by an old racer who was very successful tuning Harleys in the 30's and 40's. The only real difference was that he used a square headed grub screw and made no effort to hide it.

Tommo