Hole in piston

[Hotwings]

i've been reading posts about holes in the top of pistons being caused by the locking tool that screws into the plug hole. i've used that tool for years and never had a hole in my pistons. :?
This month in one of the heli mags there's an article about detonation and a picture of a piston that was run too lean, and a hole in the piston caused by detonation. :shock:
I personally think this is more of a cause for damage than the heli lock tool. just my $.02 :mrgreen:

Have a great week/month/year, Ron

[DavidH]

I have seen a couple of pictures posted in the last couple of years. Where a piston locking tool was used the top of the piston cracked where the tool contacted it. I use a crankshaft locking tool. Much safer in my opinion. Also have to take the back plate off the engine anyways to check for debries that might be in it. So use the crankshaft lock then while the back plate is off.

David

[flyinfool]

Although the piston lock tool may not actually punch a hole in the top of the piston, it can crack or dent the top of the piston causing a future blowout that is often blamed on a lean run, that was caused by the piston leaking thru a crack in the top of the piston.
The bigger the piston diameter the more the chance of damage.
The "dent" in the piston can be to small to see with the naked eye but can be measured with a good dial indicator. I don't take much to get miroscopic cracks in the piston.
None of th eengine manufacturers recomend a piston lock tool, the only ones that do recomend a piston lock tool are the sellers of piston lock tools.