bent push rods

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1

1971demonH

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hamburg ny
fresh rebuild on 69 340 block. l2316f pistons .030 over that come out of the hole .018 standard felpro gaskets, i think .039 compressed. x heads xe274h cam. car won't start and i noticed i bent all of the push rods on the exhaust.
 
Check for coil bind or guide to retainer contact.
 
Pretty simple "use your head."

1..........valve to piston interferance, did you check it? Minimum clearance is NOT with the piston at TDC, you have to check before, "coming up and over" and after

2.........Something serious wrong IE machinist improperly fitted all valves and stems are sticking

3.......Valve spring bind. You must check this

4.......You don't have the clearance you "thought" you had, IE you got clearance with the lifter compressed, now it's pumped up, and pxpxpxpxpxxxssssssst!!!

5......Wrong cam. This happened on here with a member........got a reversed ground marine cam, that is for a reverse rotation marine engine

6.......Cam installed wrong. Hey it's happened. Especially with "advance retard" cam drives, people get the sprocket marks mismatched

There are a few other reasons, this should get you thinking.
 
A couple of questions:

You stated that this is a fresh rebuild, did it run, prior to you discovering the bent push rods? Was this first fire after the rebuild? Is the cam timed correctly?

Pull the plugs, take one of the intake push rods and stick it on an exhaust lifter, put the rockers on and roll the engine over carefully by hand; is the retainer hitting the guide? Do you have coil bind? Did you check piston to valve clearance when you put this together? Exhaust valves may be hitting the pistons.
 
crankshaft timing gear was installed in the wrong keyway and exhaust valves were hitting the pistons!:wack: thanks for the help guys. lots of good comment real fast!!!!:finga:
 
1971demonH said:
crankshaft timing gear was installed in the wrong keyway and exhaust valves were hitting the pistons!:wack: thanks for the help guys. lots of good comment real fast!!!!:finga:
Click to expand...


That should have been caught if the builder did a proper piston to valve clearance check. :evil3:
 
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