Upon start up the coolant over flow jug filled with oil after 15 seconds of running. I have a b18a block with a cylinder support system. Gsr head. Sent the head to the machine shop and they said it had no leaks and was straight. Can't find any major cracks in the block that would cause such a massive leak. Any ideas as to what the heck happened?? Everything was new in this engine build

 

What head gasket did you use? You did put the plug in the head right?

 

The plug is in the head and we used a vtec head gasket. It's 81.5 mm bore

 

Do you have a oil cooler?