>
    > Hello Paul-
    >
    > So the cause of my leaking oil has been found. I have determined that
    > quite a few of the tapped oil pan bolt holes in AL parts have been
    > stripped. I have not surveyed all the bolts - I'll be pulling the
    > engine off again to do that on Tuesday. But I did find 4 already that
    > are stripped. I pulled the bolts out & they are fine. But when
    > inserted, they cannot be torqued to the spec - they spin & spin...
    >
    > So I suppose I could thin some JB Weld and re-tap the holes, but
   given
    > my tapping skills, that sounds like a recipe for disaster. I was
    > thinking instead of cutting the heads off of some appropriately
    > sized AN
    > bolts, flooding the bolt holes with JBWeld, and then inserting the
    > bolts
    > head-side first. Since the pan only calls for ~ 8fp of torqued, I
    > figure this is a simple and reliable way to get studs for the
   stripped
    > holes that I can then put metal stop-nuts on to secure the pan.
    >
    > Comments?
    >
    > Mark (Rocky Mtn High)
    >
    > You must of read my mind. I was just thinking about your engine.
    >
    > No no don't do that. Get some helicoils and a special tap.
    > I am sure you can do it if you use the proper drill.
    > Use google to check for the drill sizes.
    > McMaster also gives the drill sizes on the web site.
    >
    > http://www.emhart.com/products/helicoil.asp
    > http://www.roadstarmagazine.com/modules.php?
    > name=News&file=article&sid=233
    >
    > In Mcmaster Carr speak they are called "Helical Inserts".
    > Available in both metric and English sizes. Come in a kit with the
    > drill
    > and special tap. I think those pan bolts are 6 mm.
    >
    > Also "Thread Inserts" that require a some what larger installation
    > holes.
    >
    > Other than the oil leak how is the p-port engine running.
    >
    > Paul Lamar ...No rotor no motor.

   I have also found several stripped threads in the same location. If
   the holes are already stripped, then helicoils are the answer.
   Small threads in aluminum are easy to strip. I think it would be a
   good idea to run a clean out tap whenever reinserting these bolts and
   use a torque wrench. Jerry


Hello Mark,

If you are going to put a threadsert into a stripped hole I would highly
recommend using keenserts or even better rosan inserts over helicoils.
Helicoils are much more fragile and more suseptable to pulling out if
you are not carefull. Being an ircraft application I would shoot for the
most reliable threadsert possible. In the machine shops I have worked at
we stopped using helicoils in aluminum cnc fixtures because the
loosening and tightening of workpiece fasteners would eventually strip
them out. As soon as we switched to keenserts we stopped having to do
that ever.


http://alcoafastener.thomasnet.com/category/keenserts-reg-inserts?&plpver=10&bc=3001584|1041

http://www.unirexinc.com/rosancat.htm

Rob



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