[DeTomaso] water pump mounting hole repair

Doug Braun doug at silicondesigns.com
Wed Jun 2 16:34:39 EDT 2010


McMaster-Carr lists the max OD for a 5/16-NC18 Heli-coil at 0.400" and the
hole is already at 0.375 at a different thread pitch.  I'm not comfortable
with only  0.012" more meat per side to tap into.

Doug
  -----Original Message-----
  From: Julian Kift [mailto:julian_kift at hotmail.com]
  Sent: Wednesday, June 02, 2010 1:15 PM
  To: De Tomaso List; doug at silicondesigns.com
  Subject: FW: [DeTomaso] water pump mounting hole repair


  Are you sure a helicoil insert is out of the question? Helicoils require
an oversize hole & tap size to thread the wire insert into, it maybe worth
checking what the drill/tap sizing is for a 5/16 helicoil insert.

  Julian

  > Date: Wed, 2 Jun 2010 12:32:49 -0700
  > From: kenn_green at yahoo.com
  > To: JDeRyke at aol.com; detomaso at realbig.com; doug at silicondesigns.com
  > Subject: Re: [DeTomaso] water pump mounting hole repair
  >
  > If you don't need a lot of strength, what if you cross-thread the 3/8
hole with a tap for a 5/16 helicoil and add some filler like JB weld when
you thread the helicoil in, maybe that would work?  Kind of a cludge, but
might be good enough?
  >
  > Ken
  >
  > --- On Wed, 6/2/10, Doug Braun <doug at silicondesigns.com> wrote:
  >
  >
  > From: Doug Braun <doug at silicondesigns.com>
  > Subject: Re: [DeTomaso] water pump mounting hole repair
  > To: JDeRyke at aol.com, detomaso at realbig.com
  > Date: Wednesday, June 2, 2010, 11:33 AM
  >
  >
  > For two reasons
  >
  > 1) Because I don't want to ruin the valuable 1970 original water pump
  > casting by drilling it's thru hole out to 3/8".
  >
  > 2) The judges check the heads and head markings on the water pump bolts.
  > These are indented head bolts which if you file down an indented 3/8
head,
  > the indent will disappear.
  >
  > Do you think that not enough meat will be present in the casting to
support
  > the threaded-insert?
  >
  > Doug
  >
  > -----Original Message-----
  > From: detomaso-bounces at realbig.com
  > [mailto:detomaso-bounces at realbig.com]On Behalf Of JDeRyke at aol.com
  > Sent: Wednesday, June 02, 2010 10:25 AM
  > To: doug at silicondesigns.com; detomaso at realbig.com
  > Subject: Re: [DeTomaso] water pump mounting hole repair
  >
  >
  > Doug, since you seem to want to rescue this thing at any cost, why not
take
  > the oversize 3/8" bolt and carefully file its hex down to a 5/16"-size.
In
  > place, no judge will see the bolt threads or shank. Whatever, good luck-
J
  > Deryke



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