Why did I break valve springs??

I'll tell you why they bent pushrods....because they forced Bob Christo to take a pass even though he was afraid of hurting the motor! John Jr. said "Don't worry...you can't hurt this motor!...Everybody races this car and it NEVER breaks!" When Bob came back to the pits with the motor rapping, he looked like he'd seen a ghost! :laugh: BTW Alan, just who was it that just happened to have those two "spare" pushrods that they threw in the motor? Oh, that's right! ME!! It's a good thing I carry so much spare crap with me in the trailer wherever I go, huh?! :laugh:

 

Thanks for the info Mike and Bruce. I pulled the intake and timing cover off last night and discovered at least another issue if not part of the same problem.

First off, there was no damage on the inside of the timing cover, including the cast "button" for the front of the cam. Also, the cam gear had not as badly damaged as the distributor gear. In fact all of the teeth were intact, but worn substantially more than normal.

As I pulled the lifters out, all of them came out easily except for the #7 intake lifter. It required a little more effort and upon closer inspection, roughly half of the snap ring at the pushrod cup (top of the lifter) was gone. It also looked like the pushrod cup was cocked due to the missing piece and there was slightly more wear in the area from the pushrod.

Once I got the cam out, I noticed that the #7 intake lobe was worn down quite a bit and even had a slight flat spot on the opening ramp. I haven't put a mic on it to see how much wear is there but it's very noticeable to the eye. Taking a look at everything else, I couldn't find anything. My main concern, the cam bearings, look to be in excellent shape.

Are these two separate issues? I realize that the snap ring breaking caused some issues with the lifter operation and most likely let to the failed lobe. But I'm still not sure why the cam gear/dist. gear had issues. Unless the piece of the snap ring went through and found it's way between the gears.

Anyone have experience with the lifter snap ring failing? Just wondering if too much or too little preload could have resulted in it failing or if it was just a freak thing/failed part.

Thanks again for the comments thus far.
Paul

 

I had a snap ring pop out last year.....no damage though.

Even though there is no mark on the button on the timing cover the cam still could have been moving around. I doubt it though since it gets pushed to the rear when running.

I doubt that a piece of snap ring made it into the oil pump but it is possible. The drift pin in the distributor is supposed to break if the pump locks up and I have seen it happen. I epoxy a dime over the flapper on the stock oil pickup to prevent any chunks being sucked up and high rpm/suction....forces everthing thru the screen.
Maybe there is a quality problem with the dist or cam gears or the covers are getting the gear alignment off.

Bruce