How do I tell If I have a bent rod?
#1
How do I tell If I have a bent rod?
Long story short my car went lean at idle. I lost a spring and bent the push rod on the #1 intake valve. I looked with a bore scope and the valve never made contact with the piston. I'm hoping a new push rod and spring will get me going but I'm worried I could have a bent piston rod. Is there a way to check without taking the head off?
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Long story short my car went lean at idle. I lost a spring and bent the push rod on the #1 intake valve. I looked with a bore scope and the valve never made contact with the piston. I'm hoping a new push rod and spring will get me going but I'm worried I could have a bent piston rod. Is there a way to check without taking the head off?
So your not sure if you have a bent pushrod or a bent connecting rod??
What is the car doing? It went lean at idle?? Sounds like good luck. Lol
#6
The car went lean at idle while being tuned by someone I don't want to get into that. It has been flashed back to the original tune. Right now I know the piston did not make contact with the valve because I used a bore scope. I do have a bent push rod and the spring broken in two. I have no experience with this.. never had a car go lean. Are you guys saying if the piston never made contact with the valve the connecting rod will not bend from detonation alone? If so I'm happy to hear that.
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If you are truly worried about a bent con. rod, jack up the car as high as you safely can. Drain and pull the oil pan. Then rotate the engine 360 degrees. The #1 piston should move down to the point where you can unbolt it from the crank. Rotate the crank so you can get it out of the way, and pull the piston out. Make sure you line everything back up to TDC when you put it back together. If you have trouble rotating the crank, pull the spark plugs and pushrods. It will relieve the pressure on the crank. You might also have to pull the serpentine belt. I know its a lot of work, but it answers your question.
I can't remember if you can pull the piston completely out from underneath on the ls1, but you should be able to get it far enough out to inspect the con. rod.
I can't remember if you can pull the piston completely out from underneath on the ls1, but you should be able to get it far enough out to inspect the con. rod.
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If you are truly worried about a bent con. rod, jack up the car as high as you safely can. Drain and pull the oil pan. Then rotate the engine 360 degrees. The #1 piston should move down to the point where you can unbolt it from the crank. Rotate the crank so you can get it out of the way, and pull the piston out. Make sure you line everything back up to TDC when you put it back together. If you have trouble rotating the crank, pull the spark plugs and pushrods. It will relieve the pressure on the crank. You might also have to pull the serpentine belt. I know its a lot of work, but it answers your question.
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The valve never contacted the piston, but the pushrod and valve spring are both bent/broken AND this happened at idle? Even if it went lean for a moment, I can't imagine this happening at a low RPM or idle. What was he doing???
Either way, I doubt that a pushrod and valve spring would break/bend without the valve making contact. It might not have left a major mark on the piston.... I'd be more concerned with the valve being bent and as mentioned the guide being damaged before thinking the connecting rod was bent/twisted.
Either way, I doubt that a pushrod and valve spring would break/bend without the valve making contact. It might not have left a major mark on the piston.... I'd be more concerned with the valve being bent and as mentioned the guide being damaged before thinking the connecting rod was bent/twisted.
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If the car did not have forged pistons, then you would have had a piston in a million pieces in the bottom of the pan. A cast piston will shatter at about the same force required to bend a sintered rod. But i would pull a plug and look at the cylinder with a bore scope to make sure the top ring land isn't cracked or fractured.
#13
I already looked in the bore with a bore scope and the piston looks good. I bought the engine from a totaled Camaro. It is supposed to have forged internals. The push rod is a thunder racing 7.400 .080 rod. It has dual springs but IDK how to Identify the make. The valve I was not able to see IDK if it is bent or not. But there are no marks on the piston.That is why I say it never made contact.
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i dont see anything in the video. that thing would be pretty marked up if the valve hit it...but i am not claiming to be a mechanic.
Just to throw it out there anyways, whos to say the person that built it before it went to the junkyard didn't throw a bent rod in there without checking? Or thats even the correct rod length? Downside of buying junkyard parts. New rod, new spring check the retainer and all the hardware good and run a compression test.
Just to throw it out there anyways, whos to say the person that built it before it went to the junkyard didn't throw a bent rod in there without checking? Or thats even the correct rod length? Downside of buying junkyard parts. New rod, new spring check the retainer and all the hardware good and run a compression test.
#17
i dont see anything in the video. that thing would be pretty marked up if the valve hit it...but i am not claiming to be a mechanic.
Just to throw it out there anyways, whos to say the person that built it before it went to the junkyard didn't throw a bent rod in there without checking? Or thats even the correct rod length? Downside of buying junkyard parts. New rod, new spring check the retainer and all the hardware good and run a compression test.
Just to throw it out there anyways, whos to say the person that built it before it went to the junkyard didn't throw a bent rod in there without checking? Or thats even the correct rod length? Downside of buying junkyard parts. New rod, new spring check the retainer and all the hardware good and run a compression test.
Last edited by LSCha0s; 07-25-2012 at 02:09 PM.
#18
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Push rods don't bend unless the valve hits something or the rocker arm fails or valve gets stuck in the guide. I don't care what you see on the piston.
With the parts that are damaged I would pull the head and see if anything else is damaged. It dosn't take much to bend a valve or crack a guide.
Tim
With the parts that are damaged I would pull the head and see if anything else is damaged. It dosn't take much to bend a valve or crack a guide.
Tim
#19
Push rods don't bend unless the valve hits something or the rocker arm fails or valve gets stuck in the guide. I don't care what you see on the piston.
With the parts that are damaged I would pull the head and see if anything else is damaged. It dosn't take much to bend a valve or crack a guide.
Tim
With the parts that are damaged I would pull the head and see if anything else is damaged. It dosn't take much to bend a valve or crack a guide.
Tim
Last edited by LSCha0s; 07-25-2012 at 06:40 PM.