Crane Rocker Arm Stud Failure

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09-01-2009, 03:15 PM

#21

Rage

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Quote:

Originally Posted by Thunderstruck

My dyno pulls were with the same springs, different lifters.

Also check to make sure that the pushrods are the correct length, a long shot but it is part of the process.

Don't know about the lift issue with 496 lifters, definitely something to look at there.Yes but then why no problems of insufficient oiling for all those hours? Good point

Thanks. I checked the rocker arm contact point on the valve stem tip using the current push rods and it was dead center when built.

Last edited by Rage; 09-01-2009 at 03:25 PM.

09-01-2009, 03:18 PM

#22

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Quote:

Originally Posted by TWIN-SPINS

rage i had a lifter go bad ,,,it knocked the push rod off the rocker arm,,,the hydraulic lifter would not compress at all,,,was told it could of broke the stud,,,in my case it didnt

Good point. How does one confirm the function of a hydraulic lifter to determine if one is now defective?

09-01-2009, 03:24 PM

#23

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Quote:

Originally Posted by Thunderstruck

My 502's with Crane hydraulic lifters floated the valves on the dyno at 5600 rpm, just a thought. Morel lifters didn't float up to 6000 (stopped the pulls at 6000).

That is interesting. Do you know if the valves floated with the Crane hydraulic lifters at 5600 rpm because they were pumping up?

09-01-2009, 04:14 PM

#24

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Quote:

Originally Posted by Rage

That is interesting. Do you know if the valves floated with the Crane hydraulic lifters at 5600 rpm because they were pumping up?

Don't know why but you can definitely see the airflow, tq and hp numbers drop off when the valves float.

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Last edited by Thunderstruck; 09-01-2009 at 04:19 PM.

09-01-2009, 04:22 PM

#25

FIXX

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mrfixxall

Quote:

Originally Posted by Rage

That is very interesting. Exactly how does a hydraulic lifter malfunction so that it would pump up its adjustment length and thereby hold a valve open against the valve spring preload?

oil pressure!! if the retainer clip that holds all the internals in the lifter comes out then the lifter will keep expanding and could cause the valve to hit a piston at higher rpms..

09-01-2009, 05:36 PM

#26

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Quote:

Originally Posted by mrfixxall

oil pressure!! if the retainer clip that holds all the internals in the lifter comes out then the lifter will keep expanding and could cause the valve to hit a piston at higher rpms..

Good to Know. So if the lifter snap ring is still in place this should not be a problem at present....correct?

09-01-2009, 06:34 PM

#27

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thats what broke on my lifter,the retaining spring,,,each lifter should be able to be pushed down so far,,,so yea if the clip is there and it is able to push down a little,,,i would say its good,,

09-01-2009, 07:01 PM

#28

FIXX

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mrfixxall

Quote:

Originally Posted by Rage

Good to Know. So if the lifter snap ring is still in place this should not be a problem at present....correct?

here's a little clip on how a hydrolic lifter works, if the preload is set too far into the lifter theirs no cushion on the valve trane(acts like a solid lifter) thats why i set them 1/4 to 1/2 turn..the more you tighten the rocker at zero lash the less protection..

http://www.youtube.com/watch?v=lorANZ1Tptw

Last edited by FIXX; 09-01-2009 at 07:03 PM.