What Causes a Push Rod to Bend?

brownie83 · Oct 17, 2011

hey guys and gals...
first post here...thanks for the welcome
i am trying to help a buddy. he did injector cups, o-rings and GPs. right away on start-up(after some investigation) the driver's side front(first cylinder) #2 push rod was bent. he took it apart and installed all new rods and then it idled great. drove a little bit and started running rough. pulled covers and found 2 push rods on 2nd from front pass cylinder came out of the rocker. i never had this problem with mine, want to help him out, plus gain as much knowledge as possible. what could he be doing wrong on install? any help would be greatly appreciated...
thanks
chris

G Racing · Oct 17, 2011

Is the injector seated all the way? Is he getting it in the center of the lifter on the plunger?

brownie83 · Oct 17, 2011

thanks for the reply...i think the injector is seated, never asked, but assuming the help he had...they are ok..but will have him check. i showed and explained how to get the rod in the center. again, im assuming, he is getting that correct also. any truth in turning the motor to 11oclock on damper, installing 4 sets of rods on the "up" cylinders, then rotating 360 degrees and doing the other 4? i did mine all at TDC, but was doing valves and needed to keep them from falling into the cylinder. thanks again

PatriotHauling · Oct 19, 2011

Bent? Do you have a pic?

caladash · Oct 19, 2011

Were the cylinders purged of all fluids prior to starting after the work was done?

Derek@Vision Diesel · Oct 19, 2011

Just randomly running down the road and bending one?

Or did he bend both on one cylinder? Both on one cylinder probably is piston to head contact....

brownie83 · Oct 20, 2011

caladash said:
Were the cylinders purged of all fluids prior to starting after the work was done?

yes they did...i do have a pic but cant get to it here at work. it was the first cylinder on the driver's side. the second rod back was bent bad. dont know why it happened on the pass side...but he is looking into it. i just wanted to know for my knowledge. i dont want to make the same mistakes, or forget steps. any other help will be appreciated...ill post a pic tonite from home...stay tuned

brownie83 · Oct 20, 2011

here is the rod...again, it was the 2nd rod back on the drivers side

[/IMG]

what do you guys think?

G Racing · Oct 20, 2011

improper install?

brownie83 · Oct 20, 2011

we were thinking the same thing, but its awful hard to "miss" the lifter. just want to know for future reference...maybe it was:fustrate:

HoustonRider · Oct 20, 2011

i think its bent. lol

the piston probably whacked the valve. That kicked up the rocker arm while the cam was pushing up the pushrod and it bent. Why? timing more than likely. chain skipped a bit maybe? Hi RPM can cause "valve float" where the cam/crank is moving so fast, it can't keep up.

G Racing · Oct 20, 2011

HoustonRider said:
i think its bent. lol

the piston probably whacked the valve. That kicked up the rocker arm while the cam was pushing up the pushrod and it bent. Why? timing more than likely. chain skipped a bit maybe? Hi RPM can cause "valve float" where the cam/crank is moving so fast, it can't keep up.

right away on start-up(after some investigation) the driver's side front(first cylinder) #2 push rod was bent

brownie83 · Oct 20, 2011

this happened on the first key turn after re-installing them from an injector oring and cup r and r...what you said about high rpms and timing is what i have read. thats why im trying to figure this one out. he drove the truck right before repairs were made...thanks for all the thoughts

HoustonRider · Oct 20, 2011

are the new ones any longer than the ones that are not bent? on the new ones (from what I can remember from 100 years ago), they have to have all the slack out of them, or they will jump. idk if its solid or hydraulic lifters.... its new to me

Powerstroked162 · Oct 20, 2011

HoustonRider said:
i think its bent. lol

the piston probably whacked the valve. That kicked up the rocker arm while the cam was pushing up the pushrod and it bent. Why? timing more than likely. chain skipped a bit maybe? Hi RPM can cause "valve float" where the cam/crank is moving so fast, it can't keep up.

7.3's don't have timing chains.

How many miles/minutes into it being running did this happen?