Broke Pushrod after Cam install
11-20-2011, 01:57 PM
#1
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Broke Pushrod after Cam install I'm helping my friend put a Cam in his 98 Camaro.
Its a Comp XR275HR-12 cam
intake exhaust
.566 .568
duration @ .050 intake:222 exhaust:224
Lobe lift .333 .334
lobe separation 112
the push rods are comp P/N7955 7.400 .080
The problem is we put the cam in turned it over by hand a couple times, we heard a tick noise every now and then by hand but was not consistent with.
Pulled the fuel pump fuse and started turning over with the starter heard a louder tap noise.
Stopped pulled the Rocker arms and 3 push rods on each side are bent or broken.
Just trying to help this guy out.
Don't really know where to go from here just looking for input.
Its a Comp XR275HR-12 cam
intake exhaust
.566 .568
duration @ .050 intake:222 exhaust:224
Lobe lift .333 .334
lobe separation 112
the push rods are comp P/N7955 7.400 .080
The problem is we put the cam in turned it over by hand a couple times, we heard a tick noise every now and then by hand but was not consistent with.
Pulled the fuel pump fuse and started turning over with the starter heard a louder tap noise.
Stopped pulled the Rocker arms and 3 push rods on each side are bent or broken.
Just trying to help this guy out.
Don't really know where to go from here just looking for input.
11-20-2011, 02:20 PM
#4
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Was it lined up dot to dot with #1 at TDC? That ticking was telling you there was PTV problems. Hope its not as bad as it sounds. Pull timing cover and start over
11-20-2011, 07:44 PM
#6
Broken or bent pushrods indicate a piston clearance issue or valve spring clearance issue. Either timing is off (cam not correctly timed) or you are coil binding the valve springs. With that lift and duration (small cam) my money is on the cam timing being off. With the broken pushrods, if the timing is found to be off you now will need to check compression as there is a good likelihood of bent valves since the starter was used to spin the motor.
11-20-2011, 08:02 PM
#7
Broken or bent pushrods indicate a piston clearance issue or valve spring clearance issue. Either timing is off (cam not correctly timed) or you are coil binding the valve springs. With that lift and duration (small cam) my money is on the cam timing being off. With the broken pushrods, if the timing is found to be off you now will need to check compression as there is a good likelihood of bent valves since the starter was used to spin the motor.
