Hey everyone, I usually only read the forums but im having a hard time finding information I'm looking for so here we go.

I got a 6.0 that i swapped into my squarebody truck and i had a fuel injector stick wide open and while trying to diagnose it had filled cyl 3 with gas and i went to start it and hydro locked it. Well i pulled the pan and and looked inside afterwards to see if i wrecked my motor before trying to start it, nothing looked out of place and i looked around and most things said a low rpm hydrolock shouldn't be that bad so put it back together and sounds like it has a slight rod knock. So im planning on pulling the motor later on to see what exactly is wrong and make a plan for it. My big question tho is how to i know what might be bad and how to check for sure. This is a fresh built motor and rods and pistons are new and really dont want to toss it all and start over if i dont have to so how would one check pistons and rods for any damages that arent obviously to the naked eye?

 

Typically the rod for that cylinder gets bent...if your lucky. I don’t believe in luck for the record. Most of the time, the engine starts momentarily and the bent rod breaks and gets thrown through the block. What your hearing is the piston skirt hitting the crank as it’s running, due to rod being bent...it’s now shorter. Don’t start it again. Pull it back down and see if you can find a rod. Might need a piston also, you’ll have to inspect it very, very carefully for hairline cracks. Invest in a nice set of matched injectors. Worth every hard earned penny.

 

So i had the pan off the motor before i tried starting it again and looked up inside out of fear of that exact thing and there wasnt anything that i could easily tell to be the problem. When i put it back together i spun it on the starter a while to make sure oil was primed before putting plugs back in and test firing and when on the starter u could hear two distinct "clicks" or "clunks" which id assume was tdc and bdc. Maybe a flattened bearing? I know i wont know 100% til it comes apart but maybe? Does that happen?

 

Rough on a rod bearing for sure, but I don’t think you’d hear it if it had a flat spot on it. It would be tough to see a bent rod from the bottom. I hope I’m wrong on all of this for your sake, and it’s something simple...

 

Look at the bottom of the piston skirt on the counterweight side and the counterweight too. You'll see clear indication contact is being made since the rod is bent (now too short). If not clear, mark the bottom of the piston and run starter briefly.

 

Ill definitely look for that, at this point it should be pretty obvious cuz of how much ive spun the motor. As for checking say the pistons for damage are then any tips as to how to make sure they are in good shape? My bores are toleranced to these specific pistons and im already at .030 over so id like to reuse them if nothing else

 

I hydrolocked my ls1 the same way in the driveway. Don’t know exactly if it was water or fuel but I charged and charged the battery and finally got the car to crank after getting mad and holding the key down. Drove the car all night that night 7200 rpm shifts back to back. Parked the car and went back to it a week later and as soon as it started the rod went through the block. It sounded like a bucket of sockets in the oil pan.

 

Fuel locked mine up to, couldnt keep a rod bearing in cyl 6 for very long after that

 

So i tore down the motor checked everything with calipers and everything looked okay, one rod bearing had a small circular mark in it so i replaced all of them and everything seems to be good. havent put all off a few miles on it yet so we shall see.

i did find a tooth chipped off my flywheel and broken start parts in the bell housing but thats about it

 

I had a similar problem happen in my 5.3 2 years ago. Mine never started just stopped. Maybe i was lucky but mine has been fine since. And i bought a good brand injectors that were new that did this. Went with stock e85 50 lb injectors and have been good since the swap.