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Author Topic:   pushrod went through rocker arm
timaladd
Dirt Roller

Total posts: 21
posted March 19, 2003 09:22 PM
we run a hyd flat tappet cam at zero lash w/ rhodes lifters. what usually causes this to happen. i see it happen alot at the track and am curious. rockers too loose and pushrod is getting slapped into the rocker arm. or too tight and the lifters pumped up. we only turned the thing 5800 this weekend. also, they were a new set of crane stamped 1.5 rockers. also, piston to valve clearance is fine.

SLEEPY GOMEZ
Dirt Maniac

Total posts: 199
posted March 19, 2003 09:35 PM
Piston to valve clearance may be fine up to 5700 RPM but not at 5800, this happens when the valves are floated. The valve is still open when the piston comes up. Pull the head and look for evidence of contact. SLEEPY

sdhnc29
Dirt Freak

Total posts: 467
posted March 19, 2003 10:28 PM
Be sure that your not running some of these Chinese push rod's that are on the market . I've seen a few set's of these , not sure what brand , where the tip's are not shaped properly . In affect , the push rod act's like a drill bit , and make's the nicest 5/16" hole you've ever seen .

Other than that , this is a common problem with most aggressive circle track cam grind's .

Steve

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Hendren Racing Engines
Rutherfordton , NC
(828)286-0780

superdave
Dirt Forum Racer

Total posts: 89
posted March 20, 2003 01:47 PM
I hear the later model self aligning Chevy rocker arms hold up better. Anyone use them?

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Superdave
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RC Racing
Dirt Maniac

Total posts: 144
posted March 20, 2003 02:47 PM
Steve, any suggestions for a quality hardened pushrod?

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Alltel
Dirt Full Roller

Total posts: 39
posted March 20, 2003 04:42 PM
I did this all the time with a dodge motor. Every time the motor went over about 5500 it would shove the push rod through the rocker arm. I was floating the valves in the motor. I have run a chevy motor since then. I've got two years on the motor with a hyd. cam and speed pro steel roller rockers and heavier valve springs. Turn that motor about 7200 every night without a problem.

fastrack1
Dirt Full Roller

Total posts: 73
posted March 20, 2003 08:51 PM
IF U HAVE ***** IN STUDS SOMEONE COULD HAVE THE STUD TOO CLOSE TO TH VALVE AND NOT HE CENTER OF THE PIVOT WITH HIGH LIFT CAMS THE BACKSIDE OF THE PIVOT TOUCHES AND THE HOLE IN THE PUSH ROD SLOT IS WEAKER AND AWAY IT GOES IF U HAVE ALL THE ARMS OFF USE A STRAIGHT EDGE TO CHECK

rico 08
Dirt Freak

Total posts: 372
posted March 20, 2003 09:18 PM
Another thing is hydraulic lifters need some preload,the plunger inside the lifter is riding on top of the clip and in some instances will blow it out,the zero lash types have a internal snap ring instead of the bent wire types common on stockers.zero lash will help prevent float and lifter pump-up but runs the risk of lifter damage,even with some designed for it,i'd try some preload,even a 1/4 turn will help.

racer 4
Dirt Full Roller

Total posts: 34
posted March 20, 2003 09:19 PM
too much valve spring pressure

sdhnc29
Dirt Freak

Total posts: 467
posted March 20, 2003 09:32 PM
RC Racing ,

Yes we use push rod's made by CV Product's in about 90% of our engines . I've never had any problem's with any of their push rods . They are available in just about every conceivable length and configuration .

Steve

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Hendren Racing Engines
Rutherfordton , NC
(828)286-0780

Bob0092
Dirt Roller

Total posts: 16
posted March 22, 2003 10:21 AM
got to agree with racer4 gave a set of heads to my friend to use and he had them reworked with new springs and valve job called me and said two weeks in a row he pushed through rocker arms, i went up with spring checker and he 210 seat preasure when you only need 125 to 135 on hyd. changed springs and was fine

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