Proper flex hone size for M50 non vanos?

[Jon K]

I forget the exact bore of the M50 non vanos but do I match the flex hone tool to that size or do I get one close? Or do I get one a few mm larger... Help!

Also, best way to clean carbon off of pistons? Pistons will be knocked from the block.

[Bill R.]

fine, if there's any carbon at the top of the bore you have to remove that first before knocking the piston/rod assy's out. A one gallon bucket of carburator cleaner works for removing the carbon on the pistons. The kind you soak carbs in when rebuilding. Most places like autozone, checker , napa etc will have it in the big bucket. It comes with a little parts basket , take the basket out and wire the pistons together and leave them in the carb cleaner for a day or so. Remove and using a stiff toothbrush type brush ,scrub the pistons off and rinse. If you don't get it all off put them back in for another day and try again.



I forget the exact bore of the M50 non vanos but do I match the flex hone tool to that size or do I get one close? Or do I get one a few mm larger... Help!

Also, best way to clean carbon off of pistons? Pistons will be knocked from the block.