2007 4.6 2V stock head ?s

[runthatjunk]

Picked up a 2007 F150 and found cylinder 2 to have no compression.  No appearance of engine or head replacement appears to be original 200k motor.  Found removing the intake rocker allowed the cylinder to seal up.  Ended up removing about .050 from the lash adjuster (lifter) to get it to have compression.  Runs good.

Any idea how a valve could recede (?) beyond where the lifter bottoms out? it llikely moved about .100" from its original position new.  I was shocked the valve seemed to seal up with no leakage when I pulled the rocker arm.  Just can't wrap my brain around what's going on and I don't have an inspection camera.   Also going to attach a pic of an oil hole the I would think needs a plug, but not sure if maybe it's supposed to be open.

Any recomendations of a good forum for these motors?  Have posted on the FTE forum but no luck there

[WConley]

Those early 4.6 2V's had some valve seat wear issues.  You've probably sunken the valve into the seat enough to use up all of the hydraulic adjuster travel.  Your fix should work for awhile, but the valve will continue to sink.  There are probably some others awaiting the same fate on your engine.

Where did you take the material off the hydraulic lash adjuster?  Hopefully it was off the bottom.  Also, that oil hole on the finger follower is important.  It allows bleed oil from the hydraulic lash adjuster to flow out and splash lubricate the roller and cam lobe.

[runthatjunk]

Yes, was off the bottom.  Just can't wrap my head around the fact that the valve was being held open by around .050, how could the seat continue to sinK? 

Took on a 40 mile trip on the highway a while ago and it went well.  Think I'm going to leave it and see how long it holds up.  Will be a school & work vehicle only for a beginning driver, so short trips only for the first couple years.

[WConley]

Thermal expansion is the likely explanation.  You probably made your measurements cold.

Years ago I had a 4.0L Cologne V6 in a Ranger that sank all of the exhaust valve seats over 0.200".  That used up all the travel on the lifters.  Being iron heads, the valves weren't hanging open that far when I replaced them.  Pretty impressive to see them sunken that low though!  Turns out the seats were never properly hardened at the factory.

[runthatjunk]

Closing out the thread.


Got probably 2 or 300 miles and a timing tensioner went out. So pulled head since it had the problem with cylinder 2. Found the valve was tuliped causing valve to be about .050" longer than the other valves.

Also the oil hole is a drain for the bottom side of lash adjusters