Re: oversize exhaust manifold studs
Bud,
There is a thread insert called a Keensert that may be the ticket in
repairing the oversized holes on your exhaust manifold. If the DPO
drilled his oversize holes in line with the originals the job will be
easier.
These inserts are available in several popular thread sizes. They can
be had in four configurations.....English OD / ID, Metric OD / ID,
English OD / metric ID and English OD with solid center.
You want to use the metric ID but to get the proper 10X1.5mm thread
requires an OD thread of either a 5/8 inch -11 (.531" dia drill) or a
14X1.5mm (.492" dia. drill)........is there enough meat around the
flange to support these?? You and your machinist will have to
answer this question. The inserts are long and will have to be ground
off after installation. Also, the holes may have to be trued up else
the drill will follow the old repair's (mis)alignment! If the alignment is
too far off then the solid variety will be necessary.
My manifold is on the engine and I don't want to make a
recommendation unless I had one I could really eye-ball. Perhaps
some of our metal working members could respond.
McMaster Carr carries these inserts. They have no minimum charge
and will take credit card orders.
http://www.mcmaster.com
In search box type in "thread insert" and then choose "thread insert
for metal" then "key locking".
BTW: The installation tool is not necessary.
Also check out http://www.keensert.com
But they have a $50 minimum order
Metric Helicoil (or Recoil brand) are available in 10X1.5mm but the
hole diameter is .413" ("Z" size drill)... too small for your repair.
My story......
Neither site shows the solid variety but being in the machining
business I located these thru a machine shop supply company. A
DPO had stripped out the two top oil pump bolts on my XPAG 5925.
The "repair" holes were misaligned in position and angle. One was
5/16-18 and the other was 3/8-16. The 3/8's top two threads had
broken into the oil by-pass chamber causing the stud bore in the
pump body to fill with pressurized oil and always a slight leak past
the nut/washer. The DPO made off-set step-studs (by hand file!) to fit
pump body (had to be tightened just right). I pulled the engine last
August and decided it was time to do this job correctly which
required 5/16-18 and 3/8-16 solid Keenserts. They had to be
ground / filed flush and drilled to 6mm. I had to come very close to
the edge of the 3/8 diameter to get original alignment. I coated the
3/8 with JB Weld epoxy to seal.
The DPO's repair studs should be added to our site:
http://www.mg-tabc.org/techn-up/schraub.htm
Sort of like a stud version of #1crossed with #2.
I don't know if Keenserts will help you but they can be an alternative
to expensive repairs.
Bill Traill
DCO:
TC #5221
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