BBF bent pushrod

« **on:** July 28, 2011, 04:22:48 PM »

My 460 was runing like crap so I decided to run a quick compression test. Across the board 1-8 it tested 115, 115, 125, 115, 115, 115, 0, 95. I pull the valve cover on the one side, and the intake pushrod for my #7 was missing. I thought cool, the rod is probably in the intake valley and thats why I obviously have zero compression in that cylinder. I installed a new pushrod and tried to crank it over again, and twice it just bent the pushrod. What could be the cause of this? I have no clue how long the pushrod was missing either because I havent gotten too much run time on it yet. Thank you!

« **Reply #1 on:** July 28, 2011, 04:32:10 PM »

Quote from: Vegas on July 28, 2011, 04:22:48 PM

My 460 was runing like crap so I decided to run a quick compression test. Across the board 1-8 it tested 115, 115, 125, 115, 115, 115, 0, 95. I pull the valve cover on the one side, and the intake pushrod for my #7 was missing. I thought cool, the rod is probably in the intake valley and thats why I obviously have zero compression in that cylinder. I installed a new pushrod and tried to crank it over again, and twice it just bent the pushrod. What could be the cause of this? I have no clue how long the pushrod was missing either because I havent gotten too much run time on it yet. Thank you!

Guessing the valve in the spot of the failing push rod is bent in the guide and/or broken off and wont move...

Good luck with that....

GT

« **Reply #2 on:** July 28, 2011, 07:15:00 PM »

I agree with GT, may have valve to guide wear prob/concentricity...also check ur cam/lifter for wear. Make sure your rocker boss /rocker/fulcrum r not damaged too.

« **Reply #3 on:** July 28, 2011, 10:17:18 PM »

Is it making noises or anything? What's the plugs look like?

I agree with the boys, bent stuck valve, maybe a hole in a piston...........maybe even worse with maybe serious bottom end damage. Should be apparent when the head is pulled. My suspicion is because of #7 having no compression at all and the pushrod trouble and #3 10 PSI above the median. Same throw on the crank..........

I think it needs to be carefully completely torn down and see just what is up there, and why, myself..............before any more damage is incurred.......... $:-\$

Ray

« **Reply #4 on:** August 01, 2011, 08:13:14 AM »

Definitely a tear down is in order. I never run a motor if I know there are parts inside it that aren't where they are suppose to be. You can't just loose a push rod. A valve may cause the first problem but the cascade effect of pieces pin-balling through a motor can do much more harm. Find ALL the pieces before you assume anything. other issues could be lifter, pushrod tip departs pushrod, water in cylinder hydraulics the valve bends rod, river gods don't like you this week, good luck, don't assume.

Vegas

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