detonantion or FOD?

[OrionMCP]

Is this what detonation looks like?

There is a bunch of little pockmarks on the outer area of the pistons. Im guessing whoever had this motor befor me ran the piss out of it. I also found that the turbo side exhaust manifold had a nice crack in it. :?

[MikeZ]

Looks like it.

[onefast87]

teh last time i saw detonation, i could stick my thumb through the piston

[Chris86NA2T]

looks like FOD to me.. how did the heads look?

[87-85turbo]

How many miles are on that?

[OrionMCP]

It had about 115k on the motor. The heads looked ok, I guess. The cylinders had all kinds of oil in them. I was just curious as Ive never seen what detonation does firsthand before. I pulled the head just to check out the pistons. I think the only thing Im gonna use off this motor is the crank.

[Jason84NA2T]

I would bet FOD. I've seen similar damage on numerous engines. I believe it's probably from stuff falling in when spark plugs are changed. If there's no damage to the head then that would seem a little weird.

Detonation usually erodes the edges of the piston, and cracks piston rings causing the ring lands to eventually break.

[88sinZ]

never heard the abbreviation FOD before, what does it mean?

[alexz31t]

foreign object damage

[NissanEgg]

I had the exact same damage on cylinder #5 when I rebuilt the heads a few months ago. Mine happened as a result of shit falling in there while changing the plugs. I fired it up and was like what the fuck is that noise. It went away in bout 20 seconds.

[Az4u2c]

NissanEgg, what kind of wheels are those? I like them!

[RobP3ZXT]

those are the nismo LM gt4s I believe.

[Kennedy]

Az4u2c wrote: NissanEgg, what kind of wheels are those? I like them!
Nismo LM-GT4 18x8.5 et20 front and 18x9.5 et32 rear.

http://www.redz31.com/forum/viewtopic.p ... ght=#34085

[NissanEgg]

^^^^Yep. I sold 'em about 2 months ago for $900 with slick ass tires. I only paid $550 for 'em from my buddy who was getting new wheels for his '06 350Z.