Why does my engine knock now?
Why does my engine knock now? A little background, my car has always ran perfectly, but ever since i went to an autocross and beat the snot out of the car and over revved it once for a half second, it has had a slight tick to it whenever i beat on it (but not under normal circumstances). After I over revved it I noticed the oil pressure was low and i checked, and it was one half to three quarters of a quart low.
Anyway so sunday I was driving around and I noticed throughout the day that it was doing the ticking more often than usual, but not louder or anything so I didnt think much of it. So later on, my friend revved his engine, I revved back, and then went and parked the car and shut it off. I went over to his car and talked to him for maybe two minutes, and went back and started up my car and it had the worst knocking sound Ive ever heard. I had a guy that has a shop nearby listen to it (I havent driven it since it was so bad) and he was sure it was a snapped connecting rod bolt. Now given what I've said, what would cause that? Could I have weakened the rod after over revving it since it was then low on oil? and what would cause it to just let go like that when it was running pretty well fine when I shut it off?
edit this may all sound stupid but im just trying to realize what happened. I havent torn the motor down yet or even really looked at it (its back home in indiana). I just want to know if me over revving it and generally beating on it killed it or something else, Ive never had this happen before. thanks guys
Anyway so sunday I was driving around and I noticed throughout the day that it was doing the ticking more often than usual, but not louder or anything so I didnt think much of it. So later on, my friend revved his engine, I revved back, and then went and parked the car and shut it off. I went over to his car and talked to him for maybe two minutes, and went back and started up my car and it had the worst knocking sound Ive ever heard. I had a guy that has a shop nearby listen to it (I havent driven it since it was so bad) and he was sure it was a snapped connecting rod bolt. Now given what I've said, what would cause that? Could I have weakened the rod after over revving it since it was then low on oil? and what would cause it to just let go like that when it was running pretty well fine when I shut it off?
edit this may all sound stupid but im just trying to realize what happened. I havent torn the motor down yet or even really looked at it (its back home in indiana). I just want to know if me over revving it and generally beating on it killed it or something else, Ive never had this happen before. thanks guys
Last edited by Big Z; Dec 20, 2006 at 09:04 PM.
can you tell where the knocking sound is coming from?
myself before tearing into the engine, i would atleast check to make sure the rocker arms are properly torqued and check for bent pushrods.
but w/ low oil pressure, you may have spun a bearing... hope not
myself before tearing into the engine, i would atleast check to make sure the rocker arms are properly torqued and check for bent pushrods.
but w/ low oil pressure, you may have spun a bearing... hope not
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Sounds like a possible bent pushrod, if you over reved it, auto cross is very hard on the car if its low on oil, it causes starvation of oil, it may be the worst?
lifters are naturaly noisy.. but if you did some hard cornering, expecialy with low oil, you probably spun a rod bearing. id drive it around more untill something really manefests itself, or someone with a ton of LSx experience can look at it.
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Dunno, hopefully it's something like a bent pushrod or loose rocker arm, but those sounds are more of a tick than a knock. But why would you autocross your car if it's low on oil? It's also possible that you spun a rod bearing due to it not only being low on oil but also from oil sloshing around in the pan around corners and not enough getting to the pickup. Hope for the best, prepare for the worst.
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it could be a spring. i broke a spring before i tore down my motor and when i gave it some gas under like 2500 rpms you could hear a little tick then when my motor wound up it would go away.
I had plenty of oil when i went autocrossing, i checked everything out beforehand. when i over revved it, the engine ate that half a quart of oil. and all along i figured that tick i had was a bent pushrod or something so thats why i didnt get into it too much (i didnt have the time to mess with it). Also I went autocrossing back in april, i dunno... if it was damaged that bad would it have taken this long to do something? also when it started knocking i did still have 40 psi of oil pressure on the stock dash gauge, i havent checked it since then since the car is back home in indiana, im going to look at it again next week. thats why im so confused as to what happened since the oil pressure was still ok
the car is up in the gary area, in NW indiana. I did get a chance to check the oil pressure last night real quick, and the stock gauge still read 40 psi right away as it always has. I plan to pull the valve covers next week hopefully, today Im heading down to do some work on a car a friend is letting me have to drive in the mean time. thanks for the responses
