engine and drivetrain What Does This To A Head????

[2002Targa]

This head has had many things wrong with it.  Bad valves, poor build etc...  Just wondering what would eat the 2 and 3 combustion chambers like this?  1 and 4 look look normal, I've never seen any chewed up this bad...

Possibly just a bad casting?

Any ideas?

 

[gracer]

Looks like detonation.  Or a head gasket that was leaking and the head sat with water in the cylinders and corroded.  G

[roadhog0]

Looks like a shitty casting to me.

[Preyupy]

Usually steam damage with antifreeze causes that kind of damage. What do the bores look like? top of the pistons?

[Tommy]

Water/antifreeze in chamber = head gasket leaking for some time. Usually pistons in those cylinders would be clean compared to others and possibly damaged also.

 

Definitely not casting fault and pretty sure that sitting water will not do that. 

 

  Tommy

[71bmr02]

Normally with a leaky head gasket, there will be tracking and corrosion from the area of the leak into the combustion chamber.  unless the head was surfaced to the point the corrosion has been ground away there doesn't appear to be an indication of a leaking gasket.  slight shadowing from the water passages to the combustion chambers may indicate a track of liquid but then that could be image quality.

 

could be the spark plugs were not completely seated and/or the intake manifold gaskets were shot for  those two cylinders which resulted  in a lean condition. wouldn't take too long for that kind of damage to result.

 

lots of possibilities but my final answer is; a lean condition caused by faulty intake manifold gaskets

[2002Targa]

all pistons were uniform, I didn't notice any combustion chamber differences till I cleaned it up.

[TobyB]

Det.  Maybe with corrosion, too...  BMW never let a casting that looked like that out of the door.

 

That last head cut was done with a trenching machine, no?

 

t

[71bmr02]

I was looking at that first pic.  judging by the ridges and valleys the "trenching maching" left, that head may have some irregularities that would not allow a gasket to seat correctly.  if it meets the thickness numbers to make another cut, it should be done, otherwise, boat anchor time.  that kind of damage could have been done if it was sucking air between the two cylinders, much like damaged or incorrectly installed  intake gaskets

[oh2fly]

The first and last pics, when blown up look like there is a crack between the spark plug hole and the exhaust seat on #3, the right side one. That kind of corrosion is indictive of water seeping into the chamber for a longish time turning to steam and messing with the mixture=lean condition. I wouldn't keep that head if it were mine. Save the front cover for the next candidate, though.

[FunkyLaneO]

based on the marks on the exposed portion of the deck (exposed to the combustion chamber) it looks like something may have bounced around in there, not anything as big as a piece of a ring (I know what that looks like unfortunately) but maybe a spark plug electrode or something like that.

 

just another possibility though corrosion seems more likely.

[Tommy]

all pistons were uniform, I didn't notice any combustion chamber differences till I cleaned it up.

 

In that case I would assume that the damage has happened before previous rebuild. Probably the deck has been cut also which has removed the damage on gasket area. I'm still voting for long time head gasket failure between cylinders and water passage.

 

  Tommy