Broken valve spring, bent pushrod
Thread Starter
Le Mans Master
Joined: Dec 2000
Posts: 5,245
Likes: 25
From: Blue Ridge Georgia
Broken valve spring, bent pushrod
This motor is in my 73 Z-28 Camaro, I have about 100 miles on a new 383 stroker. All of the miles are regular driving. Went out for a ride thanksgiving day and kicked it a couple of times, ran great. Drove about 15 miles @about 45 miles per hour to get back to town and turned into a parking lot and all of a sudden it started running like crap. Finally found that the valve spring on #7 intake had broken and the push rod was bent. Pulled the head and the valve had NOT hit the piston. No mark on the piston or the valve. The valve might have been adjusted alittle loose. Called Comp and they are sending me a spring and a push rod. The cam is a XE268 with 993 GM heads. I think it must be a spring failure. What do you guys think?
Le Mans Master
Joined: Aug 2000
Posts: 6,362
Likes: 7
From: Brazos TX
Cruise-In IV Veteran
Cruise-In V Veteran
Re: Broken valve spring, bent pushrod (Paul 75 L82)
That sounds like it to me. No reason that a loose rocker would break a spring and bend a pushrod. How high did you rev it? What does the broken spring look like, does it have short tears in the metal before it completely broke? If so it is a stress riser fatigue failure. What did Comp Cams say about it?
Thread Starter
Le Mans Master
Joined: Dec 2000
Posts: 5,245
Likes: 25
From: Blue Ridge Georgia
Re: Broken valve spring, bent pushrod (burners)
I'm using the 1.52 roller rockers. The spring broke clean 1 coil below the top of the spring. Thank God for inner springs. Comp wasn't to good about it all. They are sending me a spring and pushrod, but I had to pay for the FedEX charges. I didn't know if they were going to give the the spring and rod, but I made sure that he understood that we have over 41,000 active forum members with 450,000 threads and 4.5 million posts. Power to the Internet.
Burning Brakes
Joined: Oct 2001
Posts: 860
Likes: 40
From: Woodforest
Re: Broken valve spring, bent pushrod (Paul 75 L82)
Sounds like you need to check your valve chain geometry. Did you change rockers? If so, your pushrods may be the wrong length. That could cause bent pushrods due to coil bind. May want to check other pushrods as well.
Race Director
Joined: Nov 2000
Posts: 11,872
Likes: 12
From: Waterloo ontario Canada
Re: Broken valve spring, bent pushrod (Paul 75 L82)
Since you have the head off and if you don't know how I could explain in detail how to check for proper setup of the head. This is proper spring installed height, check for spring bind, check proper retainer to seal/ guide clearance.
I will not go to the trouble of posting this if you already know.
I will not go to the trouble of posting this if you already know.
Race Director
Joined: Sep 2002
Posts: 10,362
Likes: 5
From: San Diego - Deep Within The State of CONFUSION!
Re: Broken valve spring, bent pushrod (norvalwilhelm)
Yes I wanna chime in here too: There is more to it than just a broken spring if it took the pushrod out with it. Sounds to me like the springs' compressed height is less than the spring spec says it should be. Let us know.
I've had a ROCKER fail on a new motor with about 35 miles on it. Scared the duck doo doo outta me! :mad But all I had to do was put another rocker on it and then it went 5 years before I sold the car. Your case is a bit different obviously so I'm curious what's happening.
I've had a ROCKER fail on a new motor with about 35 miles on it. Scared the duck doo doo outta me! :mad But all I had to do was put another rocker on it and then it went 5 years before I sold the car. Your case is a bit different obviously so I'm curious what's happening.
