Hello fellow noccers, I removed my primary side cover to investigate why the oil level was rising in the primary chain case of my 1962 650ss.
When I removed the stator housing one of the threads in the crankcase was stripped. The two other blind holes have a depth of 15mm but the depth of the stripped hole hits a stop after about 25mm or more. I am guessing it is so deep that I wonder if my depth gauge passes right through the crankcase and lands on the crankshaft. If that is correct I don't want to drill out and fit a heli-coil as the debris is bound to enter the crankcase. I now need to find a fool proof fix for the stripped hole.
Apart from removing and stripping the engine can anyone suggest the best way to carry out a reliable fix? I have thought of a soft tapered aluminium plug or even of a metal filler. Yes I know I should remove the engine but I am hoping someone can come up with a magic repair.
Looking forward to your helpful tips.
Roger
NO need to drill
Roger,
I would still use the Helicoil repair.
In the instructions it states that it is not necessary to drill out the hole if the parent material is aluminum.
I would put plenty of grease into the hole first and plenty on the tap and only tap the minimum depth required. And as Philip suggests you could flush the hole and remove the sump strainer to remove any debris .
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As you can see from the photographs of inside /outside my Mercury cases.......all the primary case holes are drilled through roughly the same thickness of metal. But slightly thicker metal for the alternator stator cradle holes.
The easiest and quickest fix to you dodgy screw hole is to rethread a size larger. This can be done in situ. Use grease on the tap to catch the shavings and then flush the hole and sump with petrol. Any small escapees with not damage the oil pump on their way to the oil tank filters.