Blown HG pics

[thedon809]

Any ideas as to how the HG blew like this? Only thing I can come up with is cyl #1 burns oil and somehow it caused this to happen?

http://i272.photobucket.com/albums/jj197/thedon809/IMG_20121222_173200.jpg

[85boostbox]

Yea looks like it gotten too much pressure maybe from the oil and that is what gave out. Maybe...

[shadow88]

I've seen 2.4L N/A do this, 2.2L turbos and 2.2/2.5L N/A fail like that and even the 2.6 Mitsubishi engine fail head gaskets like that too.

The only thing I would check is head and deck flatness. You're looking for a flat surface to within .004" MAX using a straight edge and a feeler or thickness gauge.

[thedon809]

The head was resurfaced when I bought it. Never checked deck flatness. I figured cast iron has to be hard to warp.

[shackwrrr]

usually abnormally high cylinder pressures create problems there if the deck/head is flat, Probably from detonation. also check the head bolt holes directly forward and rearward of that blown spot for debris or burrs in the threads, could be a clamping issue.

Did it groove the head?

[thedon809]

There was some carbon buildup on the head and block but didn't appear to damage either. This is an 85 so it only has 10mm headbolts as well.

[zin]

Oil promotes detonation, so that makes sense. Had a Nissan that blew like that, drove it home less than 6 miles and warped the deck.

"Fixed" it with a new gasket, but it didn't last, though it did get me to work for quite a few months.

Mike

[thedon809]

I've already put it back together with a feel pro hg. We shall see how long it lasts.

[Vigo]

I blew one like that with detonation on a log motor (boost control problems..). I actually heard the chunk going through the turbine. We drove the car about 6 miles after that, and in that time the combustion blowing through there ate a decent chunk out of the head in that spot and ruined it.

[thedon809]

I'm not sure if this was a progressive eating away at the HG or if it happened all at once. I didn't see any damage to the valves, piston, cylinder walls, head. I didn't think to check the turbine wheel.