To make a long story short I got a B18c type r motor and outfitted it with the Skunk2 valvetrain Spoon rods, new JDM type r pistons with rings and I sent it to the machine shop to het assembled with a mild port and polish and when I got my motor back my local shop put it together w/ a Mugen head gasket and when assembled oil was leaking between the block and the head. they suggested I use an oem gasket and for arguments sake I said fine only to find out I now have oil on my plugs. Could the Mugen head gasket been good all along and the reason it is leaking been due to the machine shop? I did'nt get anything else done at the machine shop(milling etc.), what could be the cause of this? I thank you in advance for your help.

 

after first reading this I'm thinking Valve cover Spark plug gaskets. 4 small round gaskets.

 

Well I made sure everything was replaced in the motor and all gaskets were all replaced with Honda parts. I figured if I covered these bases it would be pretty much a brand new motor only to have something like this happen. I am 100% confident in the parts that I bought for my car I just cant fathom what could've happened at that machine shop.https://honda-tech.com/zerothread?id=888664 (pic of it in the car)

 

Anybody have any ideas on what the machine shop could've done wrong? Thanks again.