Hi everyone. I just finished building my second 6.0L. The first one lasted 6k then spun a rod bearing. This time its bored 30, forged bottom end, comp 273lr cam, ls6 intake. I busted it off yesterday and there is a chirping every 2nd revolution. There is not a belt on the car and the tranny is not yet in. The chirp sounds like it is coming from the drivers side. anyone know what this could be?

 

A sign that building engines isn't your bag? But seriously, what bearing clearances did you measure at the rods & mains, and how did you measure them?

 

LOL. I would of paid someone after my 1st failure.

 

Sounds like you have 2 rods that can be rubbing together. Did you pull all the plugs out and see if you can turn it over with a ratchet by hand to see if there might be some binding?

 

Check and tighten the spark plugs, I have heard a loose plug "chirp" air out on the compression stroke while cranking. just a thaught

 

This is a great point and definitely worth checking.

 

The first go around i plastic gauged the clearances. This time I had a shop put the bottom end together for me. Rods rubbing would be every revolution not every other right?? I marked the harmonic balancer with white chalk and it does chirp every other revolution. If its every other it has to be exhaust or intake i believe. The lifters are new. My pushrods are comp and are not bent. Rockers tight. I put the plugs in before i put the heads on so i dont see that being an issue but i will check. The motor turns over without binding. would a clogged vacuum line chrip like this? when i turn the motor with the throttle pinned in full flood it chirps too. and its consistent. i will check the plugs tomorrow any other ideas to throw in the pool??

 

If your heads are machined for tapered-base spark plugs and the parts counter guy sold you flat ones, or vice versa, this could cause your chirp even if they're tight.

 

Maybe push rod diameter too large, rubbing on passage in heads? Aftermarket rockers rubbing inside heads? Just thinking out loud...

 

A rocker that isn't getting oil.... Had the exact same thing and I had a collapsed lifter that I couldn't hear.

 

the pushrods, heads, and plugs are the same ones i had on the last motor and there wasn't a squeak then. could that be the difference in lifters from oreillys for $13.00, and the ones from gm for $ 50.00 ?

 

its raining today so no work for this guy. i will have time to go give it a look over and i will check everything out and post what i find.

 

Take the valve covers off and see if ALL of the rockers are getting oil. I had one that took about 2 mins to get oil even after being warm or just ran

 

alright guys found the problem. thanks for all the help it was my dumb mistake that made it chirp. i had the problem narrowed down to the drivers side so i pulled the plugs and turned over the motor. the chirp was gone. that narrowed me down to something compression related so i had someone turn the motor while i listened with a hose to try to isolate the problem. when i pulled my hose up to move it to another location i noticed there was gas on the end of it. long story short i had swapped my drivers side head with the passenger and a guide rod stayed in the head with one in the same side of the block so when i torqued the head down it smashed the guide rods off deep in the head and block. luckily the one in the block was exposed about a 1/4 of an inch and i was able to remove it. thanks for all the replys