rebuilt top end, knocking now

[DFracing]

alright guys, so i recently had my 4.0 sohc motor rebuilt. and i put the motor back in the truck, and think everything is fine and dandy, get everything hooked back up, get the exhaust hooked, and start it for the first time, and a very loud knocking coming from the motor. definitely coming from the top end, drivers side. Its really loud. also the oil pressure guage flickers. it will be going back to the shop monday but hell if IM pulling motor out of the truck again. wanted to see what you guys thought. i have a video i will upload if i can remember my photobucket login

 

[DFracing]

 

[DFracing]

also the engine is not throwing any trouble codes. so no misses or anything like that

 

[DFracing]

no ideas?

 

[RonD]

No ideas.
Almost sounded like an exhaust leak, then you could hear a metallic knock.

 

[DFracing]

No ideas.
Almost sounded like an exhaust leak, then you could hear a metallic knock.

definitely not an exhaust leak, the engine surges really badly.

 

[aspevacek]

Do you have a scope to look in each of the cylinders? May be a good place to start looking and pull Valve covers and take a gander in there. Have not played with the OHC 4.0 so not sure if the block is alu on them or if it is an iron Block. If it is Alu it is very likely th esound is in the bottom end and just sounds like top end. The aluminium can make findign sounds really hard at times.

 

[DFracing]

Iron block alum heads. Knock is definately top end. Not a rod it would run decently if it was a rob bearing. I don't have a scope. It's going to the shop tomorow