Thread: Detonation! Can Block Be Saved?

machinist I took the block to said that it was possibly caused by the head lifting under boost and the coolant running into the cylinders which caused the damage on the hot exhaust side of the engine.

-G

lol, your machinist is an idiot.

Its caused by detonation. The first place detonation goes for depending on the sevarity of it is the top edge of the block. Which is why your headgasket pushed out and broke. Im sure the cylinder head in the same area by the firing ring has the same damage maybe just not as bad. Lol. Coolant hahahaha.

Next place detonation attacks is the ring lands. Your motors probably had just slight detonation if you didnt really notice any changes to how the motor ran other than you started losing coolant or pushing coolant out of the radiator under boost. Heavier detonation will do that and break ring lands. Im sure your pistons around the edge as well are pitted and eaten away. Detonation, detonation, detonation. Been there done that.

Most likely caused by too much boost, too much heat being left in the cylinder creating hotspots and too much timing can be related as well as a/f ratio. Many things can attribute to the detonation.

My HG didn't break. I never noticed a loss of coolant. The only thing he saw was the block. Top of the pistons are damaged, but I don't think the ring lands are. The block is warped a little(not flat). I don't know, what he said actually made sense to me at the time, but don't know -- I thought it was detonation as well. I think he thought the head was lifting near cylinder 3 and 4.

When you pull the pistons out look at the ring lands, it will be apparent if they are cracked between the top and second ring.

Here are pics of the piston in cyl #4. The last pic is of the other side..you can see it has some scratching on the side: