Quote:
Originally Posted by ctwright
I would fill the crack in with jb-weld and smooth it down and make sure it's not going to stick to any of the valves and then let it set.
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There are so many ways that this won't work. Not being a jerk, but just don't do that.
First of all, JBWeld is an epoxy putty impregnated with steel. Its plastic with some metal floating in it. Within the first few seconds of firing the engine, it will melt and come off making a horrible mess. Those flame fronts in a chamber can reach 1800-2000 degrees F. JBWeld is also not going to stop the crack. You're talking about a fracture in a casting. It will continue to grow. Stuffing it full of JBW to stop a crack in iron is like filling a crack in the sidewalk with silicone and expecting it to not continue cracking.
Plus that says nothing about the potential for messing up the valve seats.
Toni... A cracked head is a done head, especially when its between the valves. It won't last 2 years, especially if you have a coolant leak and a misfire. My guess is that the misfire is caused by the crack exerting pressure on the valve seats and not sealing them. Keep in mind that valve jobs use tolerances as low as .00012". It doesn't take much to get a valve to not seal on the seat. It might last another month, so save yourself the headache of doing all the labor twice and just buy a rebuilt head for it.