bent / broke push rods
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Instructor
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bent / broke push rods
i have the oringinal 327 350 hp, but with different heads right for that motor, had motor cleaned up block clean & checked all ok, heads cleaned checked new valves & springs, everything else in motor is new, i put together got running ran maybe 15 miles & it started bending & braking pushrods, though timing off, checked but i think it was ok, is there anything else that would brake pushrods, they only went 10 over on pistons and cam is about stock, this makes no cents to me, hope someone can help thanks peter
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From: Who says "Nothing is impossible" ? I've been doing nothing for years.
Makes sense if you didn't check the valve train geometry, you can't just bolt on new heads without doing that. The pushrods are probably too long
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it ran ok, i put new push rods in when rebuilt motor, after they broke i used the old ones, also i adjusted pushrods in stand, but # 3 piston, the push rod is still loose and that is the 1 that broke, the loose pushrod is know after the pushrod broke thanks peter
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Burning Brakes
Joined: Dec 2003
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From: Adelaide South Australia
Just something else to consider...
I bent a couple of pushrods in my original 327 too.
It was due to the (pressed) rocker studs coming loose and in turn having the pushrod fall off the rocker and then jam against it.
I bent a couple of pushrods in my original 327 too.
It was due to the (pressed) rocker studs coming loose and in turn having the pushrod fall off the rocker and then jam against it.
Le Mans Master
Joined: Jun 2004
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From: Seattle WA
St. Jude Donor '14
Something has "gone solid" in your valvetrain. Check for coil bind and all other clearances (rocker/stud, valve seal etc.)
Common post-upgrade issue when clearances and geometry aren't checked :-(
Common post-upgrade issue when clearances and geometry aren't checked :-(
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Le Mans Master
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From: Seattle WA
St. Jude Donor '14
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the way all the vette books say to adjust with engine off you start with tdc adjust some intake and some exhaust the rotate 1 full turn to tdc and adjust the rest but # 3 push rods still loose thanks peter
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From: Forked River NJ
I'd get a new book. I have built many engines in my time and never adjusted hyd or solid lifters this way. You either have coil bind or you are hitting a piston.
Team Owner
Joined: Oct 2004
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From: altered state
St. Jude Donor '05
Youre not hitting a piston.
Check the other items as the other posters said.
If you got a set of cheapo pushrods those can give way too.
Had it happen to me with a set of .080 thick ones. 670 lift no piston to valve issues. First time I got on it then all bent, 1 broke.
Some look the part and are simply cheap junk.
Check the other items as the other posters said.
If you got a set of cheapo pushrods those can give way too.
Had it happen to me with a set of .080 thick ones. 670 lift no piston to valve issues. First time I got on it then all bent, 1 broke.
Some look the part and are simply cheap junk.
Le Mans Master
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From: Seattle WA
St. Jude Donor '14
The only means to adjust the valves with 2 positions is the "companion cylinder" method. I used this very commonly, but it isn't always the right choice with extreme cams.
Here's a short post I wrote with how to do this - it requires that the mechanic effectively determine zero lash...and being honest, with you starting the engine KNOWING you had a "loose" pushrod, I would get some help with this. That sounds a little harsh, but I'm trying to help you avoid more issues. You STILL need to check all the valvetrain clearance and geometry before doing anything else...if you're not sure how to do that...again, experienced assistance is required. Post on the board here in your local forum and I'm sure one of the great folks here will step up.
http://forums.corvetteforum.com/1578518901-post7.html
This article provides more background on the approach:
http://www.carcraft.com/howto/ccrp_0...aft/index.html
Another approach that works with ALL cams is the "intake opening/exhaust closing" method - this is in virtually every service manual so shouldn't need to be restated here.
Again...you need to get some experienced assistance here before you break something big-time...if you haven't already
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Instructor
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i found the loose pushrods after i tore the motor down, i didn't run the motor with loose pushrods, i'm smarter then that, i did adjusted the valves with the intake open/exhaust closing method ( that is when i found the loose pushrods the motor is still on motor stand, and until i can find the problem it will stay there i do thank everyone for the help there giving me peter
