Low cylinder compression

tireman3 · Mar 27, 2013

I recently did headstuds, new oil cooler, egr delete with the cab off (06 F250). After i got everything back together and cab back down, went to crank truck and had a loud banging from driver side. Pulled Valve cover off and rocker arm on #4 had broken(plastic clip failed). I installed new rocker arm and pushrod. Cranked up and no more banging but #4 injector was inop. Towed it to local Ford dealer and he ran test and suggusted we try an Injector, which made sense. After injector compression on #4 is at 18% i believe. Ford tech is suggesting maybe it was something in the head job that was done. Heads were checked and decked by a very good machine shop. Any suggestions or ideas of what to do from here?

DEEZUZ · Mar 27, 2013

plastic clip only keeps the rocker on long enough until fulcrum is torqued, has nothing to do while rocker is under tension of pushrod and valve bridge. chances are you didnt have the pushrod lined up correct and you smacked valve with piston....

tireman3 · Mar 28, 2013

so from here what do you recommend I do for repair? Already planning on pulling engine some time next week

kyle43335 · Mar 28, 2013

tireman3 said:
so from here what do you recommend I do for repair? Already planning on pulling engine some time next week

pull engine. remove head. inspect.

tireman3 · Mar 28, 2013

so could it be a possibility that the head was shaved to much?

kyle43335 · Mar 28, 2013

tireman3 said:
so could it be a possibility that the head was shaved to much?

being that you have a broken rocker/ bent push rod, i would say ctc is on track with a bent valve.

but i have seen first hand, how those "machine shops" that know so much, *** the pooch royally on machine work in general.

its anyones guess right now. the head has to come back off, and the valve on that cylinder must be inspected.

there are ways to test to see whats wrong. but i doubt you have the equipment to do that.

tireman3 · Mar 28, 2013

Just to clarify the rocker arm did not break, the plastic clip broke and the push rod was not bent. I just replaced both to be on the safe side.

blackie375 · Mar 28, 2013

remove rockers on that cyl,put air in cylinder and you should find out what valve it is

907DAVE · Mar 28, 2013

Lesson learned, always bar an engine over by hand before buttoning it up.

Snoop · Mar 28, 2013

907DAVE said:
Lesson learned, always bar an engine over by hand before buttoning it up.

True that. Was just thinking of how much it's a pain in the ass when I pull the motor (instead of pulling cab) to do head work, but I'm forced to spin the motor to bolt up the TC. Spin it by hand to make sure everything is golden.