49133 Mercruiser STUD, CYLINDER HEAD

Introduction
The problem that is identified below does not have a known permanent solution. Until a permanent solution is known, use the solution that is identified below.Problem
Certain areas of the oil pan can exhibit signs of cracking due to insufficient stress relief of the casting.Solution
Do not operate or work on this product unless you have read and understood the instruction and warnings in the relevant Operation and Maintenance Manuals and relevant service literature. Failure to follow the instructions or heed the warnings could result in injury or death. Proper care is your responsibility.
Peening specific areas of the oil pan can add strength to problematic areas and increase the oil pan life.Rework Procedure
Inspection process
The needle peening process outlined below can be completed on select 230-1070 Oil Pan As. To determine if the needle peening procedure is recommended, complete the following inspections.
Illustration 1 g06574752
Part number locations
Inspect the part number cast into the bottom of the oil pan. Oil pans with part number 230-1071 Oil Pan are believed to be at low risk for cracks to occur. Oil pans with part number 230-1070 Oil Pan As cast into this location have a higher risk for cracking.
Illustration 2 g06574811
Pan Stamp
On selected oil pans with part number 230-1070 Oil Pan As cast at the bottom of the pan, additional actions have already been taken to reduce the risk of failure. If a "HT" or "P" is found stamped in the location seen in Illustration 2, there is no need to perform the following needle peening operation.
Illustration 3 g06574906
All dirt, grease, oil, and paint will need to be removed prior to performing the needle peening process. The needle peener can be used to remove paint, however, all process times are not cumulative, and actual peening process time initiates after paint is removed.
Illustration 4 g06574917
Typical blunted peener needles
The peening process consists of using 3 mm (0.12 inch) blunted needles as shown in Illustration 4, not pointed. Pointed needles will break and / or damage the pan. The air pressure to the peener should be regulated between 186 kPa (27 psi) to 207 kPa (30 psi). Peener should not remain in one place and must be continuously moving to cover the entire area.
Illustration 5 g06574926
Rough surface texture
Excessive air pressure will result in the following rough surface texture and must be repeened for the full amount of time to be correct. Refer to Illustration 5 shows correct surface texture.
Illustration 6 g06574929
Large needle impingement
Illustration 6 is representative of 586 kPa (85 psi) and is not beneficial, note the larger needle impingement areas.Rework Procedure
Illustration 7 g06574950
Location of the area needing peened
Overview of oil pan with area to be peened. Refer to Illustration 7 showing the area needing peened with a circle.
Illustration 8 g06574956
Area that is blued
Apply bluing to the area shown in Illustration 8 and let dry. Bluing the surface ensures that coverage of the peening is consistent.
Illustration 9 g06574962
Area needing peened
The entire area can be covered in about 30 seconds, which should be enough time to remove all the bluing. Continue to peen over the area for another 30 seconds to complete the process.
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