I have an fd single turbo with a rebuilt engine with only 5000km on it.i change the oil and on the magnetic bolt of the oil pan i found really small pieces or iron wear.did the guy eho close the engine did something wrong?

 

Can you take a picture of what you found on the plug? A dark grey paste is normal as a result of bearing wear, it can be greater with new bearings as they are breaking in.

 

I cant take a picture because i changed the oil.but is more like very small pieces of iron than a paste

 

Did you just put the magnetic plug in recently? The first time I changed my oil after putting in a magnetic plug I was amazed/scared. The stuff obviously had been floating around over many years. The second oil change was 1000 times better.

 

No i had the bolt since i put the rebuilt engine.the other times that i change the oil there were some iron wear but i thought that was normal but this time it was a lot

 

You just rebuilt the engine.,Expect the thing to get broken in and shave a little here and there.
Things gotta fit somehow.Nothing will be absolutely 100% perfect on a rebuild.