Author Topic: AAZ Piston Damage question (Read 3129 times)

HarryMann · « **on:** January 15, 2007, 06:38:17 pm »

Is this piston 'nibbling' recognised as normal after a glo-plug break-up incident or perhaps through detonation by running on oil?

Thanks for any comments, two other pistons show similar signs but much less severe, making me think it isn't that uncommon.

Rings aren't broken as far as I can determine, used to breathe a bit, but didn't burn much oil at all - would you stick the head back on and try for another ten thousand miles?

speedy · « **Reply #1 on:** January 15, 2007, 07:29:41 pm »

Where I come from that is called a burnt piston. Usually happens from detonation, but I only have experience with the internals of gasoline engines. Maybe diesels are different since they detonate by design? Regardless, that does not look like a good thing to me.

-Dave

craiggroombridge · « **Reply #2 on:** January 15, 2007, 10:10:53 pm »

I have seen this on case tractors the piston is falling apart, starting to break small pices off, the more off the more unbalnced the more off etc...
i think you need new pistions, sorry for the bad news

Craig

houseofdiesel · « **Reply #3 on:** January 16, 2007, 03:27:59 pm »

I always thought when the edge of the piston is eaten away like that is was poor injector spray pattern as it right under the combusion chamber outlet. I would not consider those "finished" as I have taking many engines apart with pistons like that and machine shops don't comment on them...you might want to weight them all and match them within a gram.
I would get new injector tips for sure.