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Tools for Testing Engine Cases for Cracks at
Oil Cooler Pad


May 2006 ~ Indianapolis, Indiana
Mike Robbins ~ Tech Article #2

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Materials Required:
1.
 Surplus 3rd piece of engine case. Can be damaged except for lower left corner. Require piston, copper seal and threaded plug for relief valve. Spring not needed. 6. Seal for oil cooler
2.
 Block of metal approx 2" x 4" x ½". Soft metal preferred as easy to work with. 7. M6 wave washers and nuts
3.
 Pressure gauge with 1/8"NPT male thread...0-at least 150psi 8. M8 x 35mm or longer bolt, flat washer
4. Schrader valve w/ 1/8" NPT 9.
 2 seals for 3rd. piece to case.
5. Wood dowel rod ½" x 2" 10.
 3 M8 wave washers and nuts
Note: Dimensions of hole spacing are not included. You’ll have to determine those from actual parts.
[Saves me the time of making drawings] MR


Tool  A
View 1
a.
 Cut approx 6" x 2 ½" corner from an extra 3rd piece.
b.
 Tap hole indicated 1/8 NPT and screw Schrader valve in place.
c.
 Install piston, dowel rod, copper seal ring and plug in relief valve bore.


Tool A
View 2
a.
 Plug hole solid with rod & epoxy.








Tool B
View 1
a. Fabricate block for mounting on oil cooler pad. Note that step is req’d so that one end will fit over M6 stud in top of case and other end will be thick enough to provide for counterbored hole for oil cooler seal and threaded hole for pressure gauge. Read ahead [I happened to have a piece of aluminum that had 2 corners cut and a hole in it.]
b.
 Counterbore hole for oil cooler seal.
c.
 In center of counterbore, tap drill and tap 1/8" NPT to receive pressure guage.
d.
 Drill 11/32" for use in bolting tool to case using hole for oil cooler stud. M8 bolt & nut can be seen in pic.


Tool B
View 2
a. Drill 1/4" hole at point [point not necessary] for fitting over M6 stud in top of case.


Procedure:
  • Place Tool A over studs on left case half and fasten w/ washers and nuts.
  • Place Tool B and cooler seal on cooler pad. Fasten to M6 stud and use M8 bolt, nut and washer to fasten to case ala cooler stud..
  • Pressurize system to approx 120 psi. Brush soapy water around oil cooler pad to look for leaks and/or listen for air escaping, if system is isolated -- watch for loss of pressure on guage (assuming test system has no leaks.)
Note:  These tools and procedure will only test for leaks on the inlet side of the oil cooler.
In >40 years of fiddling with 356s, I have never seen a case leak at the discharge side of the cooler.
~ Page last updated 5.1.2006 ~
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