pushrod hhhheeeeellllpppppp.......
08-17-2003, 10:46 AM
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pushrod hhhheeeeellllpppppp....... i am putting together a 5.3 with a lunati55003 cam duration@.50 is 218/221 lift is.526/.534 i am using lingenfelter 60.7 cc heads {ls6----cnc} the push rod i am using is a manley7.450 my question is???????is this the right pushrod for this motor ?????when i installed them i rolled the motor over and no compression ????whats the deal ...thanks 
08-17-2003, 11:20 AM
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Re: pushrod hhhheeeeellllpppppp....... Well, A 60.7cc chamber in an LS6 head is pretty small. They must be milled quite a lot. Do you have idea as to how much the head surface has been milled. Talk to Lingenfelter and find out. I would bet they are milled .050"
Even though the cam you have has a slightly smaller base circle than the stock LS1 cam, it isn't by that much since it's a fairly low lift cam.
With heads milled by that much, you certainly need [shorter] pushrods. You don't have compression because the valves are not closing completely due to the long rods (they are 50 thousands longer than stock)
Get a set of shorter rods. Since you must be bottoming out the plungers in the lifters right now (valves not completely closing), I would purchase a set of 7.35" rods. They are .050" shorter than stock and will compensate for the heads being milled .050"
Since you are appearently bottoming out the lifters, you face the chance of piston to valve contact resulting in bent pushrods and/or bent valve
stems.
Don't know who told you to install long pushrods in an engine with that much milled off the heads, but that was the exact opposite thing to do.
Get those 7.35" rods are you will be ok .... As long as you have not already bent some valves by turning the motor (sure hope not)
Ron,
Even though the cam you have has a slightly smaller base circle than the stock LS1 cam, it isn't by that much since it's a fairly low lift cam.
With heads milled by that much, you certainly need [shorter] pushrods. You don't have compression because the valves are not closing completely due to the long rods (they are 50 thousands longer than stock)
Get a set of shorter rods. Since you must be bottoming out the plungers in the lifters right now (valves not completely closing), I would purchase a set of 7.35" rods. They are .050" shorter than stock and will compensate for the heads being milled .050"
Since you are appearently bottoming out the lifters, you face the chance of piston to valve contact resulting in bent pushrods and/or bent valve
stems.
Don't know who told you to install long pushrods in an engine with that much milled off the heads, but that was the exact opposite thing to do.
Get those 7.35" rods are you will be ok .... As long as you have not already bent some valves by turning the motor (sure hope not)
Ron,
08-17-2003, 02:30 PM
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Re: pushrod hhhheeeeellllpppppp....... our forum member scogin dickey sold me this set up i called them three times and they assured me that they were the right ones...i dont think i bent any valves {i rolled the motor over by hand with a ratchet on the crank bolt on an stand}...i thought something was funny because the pushrods were longer but my heads were milled. and i understand the base circle on the cam is smaller but not that much...were talking 3/16 longer i would have been pissed if i would have tryed to start this thing up and it would have blew up....thanks for the help i just wanted to double check to make sure it wasnt me....
08-17-2003, 02:48 PM
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Re: pushrod hhhheeeeellllpppppp....... 7.450 is WAY to long. I would try the 7.350 also. Maybe they just made a mistake? 7.4 is stock and you would need shorter for sure. Not longer.