Anyone ever hydrolocked a motor?

[punchit]

quoted from friend- "drove through big mud puddle full throttle. truck shut off. took off air filter intake tube got all the water out. took off spark plugs ran motor for a little. Put spark plugs in. motor runs just has a knocking noise. and there was no knocking noise with 7 plugs in and then when i put the 8th one in it started knocking"
Any advice i could give him?

 

[aaandht]

Bent rod?

 

[jfsram]

Probably bent the connecting rod.

 

[punchit]

Thats what we were thinking but wouldnt the bent rod be knocking even with the spark plug out??

 

[ford_racer]

I think my friend told me about this type of thing. The cylinder that he pulled the plug in will be the one that's screwed up. Something about the lack of plug gives it too little pressure to be able to hear the knock.

 

[James Snover]

Not always. It could also be a broken skirt, that when the cylinder fires it knocks; it could be an out-of-round rod bearing. With no pressure in the combustion chamber, the rod rides the the circumference of the out-of-round bearing. With combustion it slams back down on the crank.

None of it is good. Rebuild for sure, probably need new rods and pistons, maybe even a new crank. Possibly a new block, too. He won't know until it gets torn down.

Jim Snover

Thats what we were thinking but wouldnt the bent rod be knocking even with the spark plug out??

 

[mifordman]

Not always. It could also be a broken skirt, that when the cylinder fires it knocks; it could be an out-of-round rod bearing. With no pressure in the combustion chamber, the rod rides the the circumference of the out-of-round bearing. With combustion it slams back down on the crank.

None of it is good. Rebuild for sure, probably need new rods and pistons, maybe even a new crank. Possibly a new block, too. He won't know until it gets torn down.

Jim Snover

+1 you may or may not be able to tell by just dropping the oil pan, somtimes you have to pull the head to see that type of a problem.