My first thought is liquid flooding. This could be continuous if the superheat was way low for some reason. It could be a piping issue that allows a startup surge of liquid refrigerant and/or oil to surge into the compressor. If this is a refrigeration system with defrost of any kind, a surge of liquid often follows a defrost. A suction accumulator may be a good investment.
The modern compressor valves are very rugged. New gaskets are more likely to fail than old baked on gaskets. Flooding can blow a new gasket and leave no evidence in the valves.
Thanks for your input its making sense. This units does have poor piping and low superheat. However, I've always thought of blown head gaskets as a compressor problem but you've convinced me otherwise.
BTW, Participate some more and go for pro.
Going Pro is my goal
Honestly, I don't understand the way this thread has evolved. Originally there was a problem with a Cope 6D head gasket missing the center bolt from a local reman shop. Was the missing bolt the problem or not? Let me tell you my experience. The center bolt was added by Copeland to prevent VALVE PLATE GASKETS from failing. Head gaskets on Cope disc type compressors are all on the high side. There is no center web separating high from low side pressures like on Carlyles or Dunham Bush or Frigidaire or Servel or ???. Get my point? I've been around and I've seen all these compressors and Cope Disc type is different. Put the bolt in, torque it to 35 ft lbs, don't use the rebuilder anymore, and call it a day! If you want to know more about Cope valve plate gasket evolution, contact me at email@example.com
Thanks Remanworld I appreciate the info. Right now I'm waiting for the parts and yes I'll install the center bolt.
Lynn Comstock is right, flooding is a probable cause. Compressing a non compressible like liquid refrigerant or oil will take the gaskets out. Do you have a crankcase heater? Does it work? Check your superheat. Don't ad oil to the system unless you know why and where the oil went. Compressors that pump oil will eventually bring the oil back, in a slug. Good luck.