Rebuilt engine problems!!

[gimmel1]

Hey everyone i just recently rebuilt my 350 motor and trans in my 94 1500, and when i started it up it ran great and idled fine the whole day . The next i ran it and moved it around the house andit was idling in the drive way and i heard a pop, after that it was missing and had no power. i did a compression test and cyl 2 was dead. also the plugs and exhaust had a thick coat of carbon. I think its a hole in a piston as it doesn't knock or rattle but im open to suggestions. need to finish please help!

 

[DRAGGIN95]

I would pull the valve cover first and make sure you can see both valves on that cylinder working normally.

 

[gimmel1]

i did that and all looks normal i also took out the push rods and the valves seem to be closed all the way. put the pressure tester wouldnt hold any pressure at all.

 

[DRAGGIN95]

That suck's man, I wish I had an easy fix for you, but it sound's like you may have to tear in to it to at least see what's wrong on that side first.

 

[darren250r]

If the valves are closed and there is no compression, you might as well pull the motor. Do you have a lot of blow-by coming from your oil fill cap when you take it off while running?

 

[FastOrange]

Hey everyone i just recently rebuilt my 350 motor and trans in my 94 1500, and when i started it up it ran great and idled fine the whole day . The next i ran it and moved it around the house andit was idling in the drive way and i heard a pop, after that it was missing and had no power. i did a compression test and cyl 2 was dead. also the plugs and exhaust had a thick coat of carbon. I think its a hole in a piston as it doesn't knock or rattle but im open to suggestions. need to finish please help!

What do you mean by "Rebuild", What was done?

 

[92GMC]

id say you broke a ring or theres a hole in your piston like mentioned.

 

[MOBS]

Do the active compression test with the air compressor type....then listen at the intake, exhaust, and cylinder side to see where it's leaking. Easiest way is to listen to the throttle body(air "whispering" sound means bent/carboned intake valve); somewhere along exhaust for the exhaust valve leak; engine oil fill(or any open passage to the crankcase), the "leaking air" sound from there would mean cylinder/piston issue. I have a question, was the engine broken in correctly or was it just rebuilt and cranked and sent out the door?

Ps. Also, to cover this slight possibility, you can see if your radiator starts bubbling after a while. That means you blew a head gasket next to the water jacket.

 

[gimmel1]

ok well first it was completly rebuilt bored, honed, new everything. i put pressure through the cylender, and i was into the crankcase, the wierd part is its not clanking or anything. and no bubbling in the radiator and no water in the oil. and no i broke it in 20 min at 2000 rpm varying rpms between 2000 and 2500. so i get to pull it apart monday yay!!!

 

[MOBS]

Good deal....I admit I love working on engines....but it's always a momentary let-down when it doesn't go smoothly. Good Luck and tell us how it goes.