What cause's a bent Pushrod?
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Postmaster
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From: Clarksville,Tn
What cause's a bent Pushrod?
I have dealt with this problem twice; it seems that a exhuast pushrod in my number six chamber is bent. The heads are factory 302 off a 76 motor. The lenght of the rods where a initial question and they are 6 7/8" long. I was thinking they where too short and that is what cause the rod to get damage. However new ones are the same lenght; Could the valve just be inoperable and that cuase it to bend the pushrod?
Thanks from a Shade Tree Mechanic with alot of leaves missing..
Mitch
Thanks from a Shade Tree Mechanic with alot of leaves missing..
Mitch
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From: Clarksville,Tn
Thanks for your replies; I guess I owe you more info; the motor is recently built with bore 60 over; 10:5:1 flat top piston; mid 268 pro comp cam; & 650 carb. I'm getting the heads rebuild as we speak; but my buddy & I are both baffle on why the push rod bent; initially thought the guy who built my engine use the wrong size p-rods; but I check mine & the ones at a-zone and it calls for a 6 7/8" lenght. Hope this helps you guys determine my problem. The heads are having a 5 angle valve job; milled & stainless valve and brass seats; as I'm told. Its alittle more data than what I understand (not that knowledge on the head jar-gun) from my buddy who's builting my heads.
Mitch
Mitch
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Joined: May 2003
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From: south louisiana
Pushrods usually get bent when the rockers get loose. You could also have had a rocker adjuster nut back off. Or if your heads still have the pressed in studs, bigger than stock cams will work them loose. Sight along the tops of the studs and see if any are taller than others. If they are, that's the problem.
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From: Clarksville,Tn
Guys; thanks for your techinical advise; I will print a copy of this knowledge and pass it along to my buddy. I also thought loose rockers would be the reason; also I thought these heads would need adjusting during initial crankup and running once on the engine as well. But my buddy stated the rockers are the type you just tight down and no adjusting needed? the mechanic that built my engine also place about a 1/8" thick washer on each rocker stud; which seem out of place to my buddy; it could of been the reason as well; seems the washer was place to close the gap between the rocker & the rod; but we can't figure out why he would do this.
Again thanks and I'll post any other info as soon as I find out.
Mitch
Again thanks and I'll post any other info as soon as I find out.
Mitch
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Joined: May 2003
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From: south louisiana
Sounds to me that you've still got the pressed in studs. They would be the "positive stop" type in which you do torque the rocker nuts down and forget about them. The washer was an attempt to keep the nut from bottoming out on the stud shoulder and give you some room to adjust the lifter preload. Either the nut worked it's way loose, or more likely the stud started pulling out of the head from the extra force applied with the new cam profile and springs.
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Cargo Master
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From: British Columbia
I once bent a couple pushrods by installing them on the edge of the lifters instead of in the center of the lifter. This was on an old Cadillac motor though, I don't know if it can be done on a small block Ford.
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the only reason I have seen anyone put washers under the rocker nut is it take up clearance in the rocker. Evey time it was the cam that was junk and was causing the clearance.......
I would pull all the washers and check the preload (you should have 1/2 turn before the nut hits bottom)
my bit is the washers took all the preload out of the lifters and the valve hit the piston bending the rod......
who's idea was it to put washers under the rocker nuts..?????
get a new mechanic!
I would pull all the washers and check the preload (you should have 1/2 turn before the nut hits bottom)
my bit is the washers took all the preload out of the lifters and the valve hit the piston bending the rod......
who's idea was it to put washers under the rocker nuts..?????
get a new mechanic!
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From: Clarksville,Tn
I'm with ya Hemieater; the guy who built my engine; is waiting for a bunch in the face from me; cost me time & money & potential future damaged to my truck; lucky I got a good friend who's only hobbie beside racing mustang's is builting performance heads. He too stated it doesn't make scense to put washer on the heads; I believe the exhuast valve p-rod was / got loose and cause it to bend the rod. Hopefully before eating Turkey I'll have my heads back on my truck. The truck is the one in my gallery if your interested in seeing it.
Mitch
Mitch
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