edm nozzel problems ?

[cornfed]

Anyone having problems with edm nozzels? I had a set done with 4 holes @.010 and 3 @ .012 and am having trouble with them cracking and breaking. This is happened twice with in 150 miles. The shop I am using is a local and reputable source for many pullers. I have had them send and install these nozzel on new injectors, and they balanced out great on the flow bench.They replaced the first nozzel and balanced for free. I installed them after giving the motor a checkout and last night I lost another one [img]/ubbthreads/images/graemlins/shrug.gif[/img]. I am running BI code injectors and was taking it easy on them. I have not been out pulling or hot doggin it. Egt after turbo has never reached 800. Is the edm process just getting them to hot making them brittle, or is this an issue of technique? Would extrude honing be the better way to go? If anybody has had any adventures in this area any thoughts are welcome.
Thankyou
Chris

[BIGBEAN]

Were the nozzles new or used?

[cornfed]

They were used but did not look blued or have any visible defects.

[cornfed]

I believe they were nozzels from factory injectors that were replaced with larger,not dipaco.