Just bought a 79 chevy 3/4 ton and went to start it and it made a loud boom noise. Looked under hood and the valve cover somehow exploded, want to know what might have caused this and where to start on the engine.. or should i just find a replacement engine for the truck.

 

 

Nothin' wrong with your engine,

You've had a crankcase explosion caused by the oil being saturated with gas. Change your oil.

Check that carb for leakdown/bad float, but most likely, this was caused by a bad choke setting.

Also, when you get it running again watch for oil leaks. You can just about bet that it blew the pan gasket and the other valve cover gasket.

Allan

 

Good to hear, ill mess around with everything and hopefully no more problems.

 

Wow first I seen this

 

It might be the crankcase pressure due to excessive blowby.

 

did compression check, turns out the motor has no compression in at least 2 cylinders so time to swap out for different one.

 

Did you take the valve cover off yet to inspect and make sure you didn't bust a valve spring or two, or something else? If valve train parts went flying apart under pressure, that could break the valve cover, and would also explain the no compression if those two bad cylinders are on the same side.