I have a 2008 6.4 with about 250,000 miles. A couple weeks ago went to take off at a light and no power so pulled into a parking lot. Very shaking idle. The whole truck was shaking and also the tell tale noise in the air intake so had it towed home.

So my first thoughts are rockers but the shaking idle has me thinking injector. Pull codes for contribution balance on 1, 2 and 8. So I started on the driver side, but when I pulled the valve cover everything looked good. Pulled the passenger side and rocker arm for cylinder 1 is off.

Waiting on an adapter to do compression testing as mine does not fit the 6.4 glow plug hole. But assuming everything checks out what is my plan of attack.

1. Should I do all rockers on both sides. 2. Can 6.4 injectors be tested, still trying to figure out why I got the codes on the driver side. 3. Can worn rocker tips cause a contribution code or could I have two bad injectors.

 

I would fix the rockers first, then clear codes and see what shows up.

 

One of the members, SpeakerFritz, has done his rockers by lifting the back of the cab a few inches - i’ll Look for his thread. Special torque sequences for the rockers.

 

The rockers are easy no need to lift the cab. Just not sure if I should do all of them. The wild card is the cel for 2 and 8 with no broken rockers. After a compression test hopefully I will know more. But if I have good compression I think it points to bad injectors.

 

Pull all of the push rods and validate they are straight.

 

I recently did

rockers
saddles
push rods

to check your push rods, you can roll them on a sheet of glass. i had 12 of 16 bent. about 4 of them were bent so bad they could not roll.

the rocker tips were worn on most, bare metal on a few, and 1 rocker was laying in the valve area.

injectors could be coked from poor fuel combustion due to vale train issues.....or they could be worn....I debated on replacing injectors and so far, I have about 8K miles since rocker job and truck is running fine.

unfortunately....lifters cant be replaced with out either pulling heads or pulling engine.

and yes..I had to lift the front about 2 inches and the back about 6, pull wheel well liners, get a set of flex joint sockets.

if you lift the cab at all, dont for get to remove steering shaft bolt and dont forget to put it back in.


some folks say they can do both sets of rockers in 1 afternoon with no cab lift....I dont see how...my 2010 had a kazillio things in the way which I had to remove. took me weeks working a couple hours per weekend.

take photos of the hardware securing the drivers side rocker cover...if you dont get those spacers and washers correct, your turbo oring will leak.

Also....I am curious if you find seals on the fuel rail portion that goes thru the valve cover ...mine had none...I I get blowby fron that area frequently...next time it comes off...Im rigging up sometype of seal soplution.


dont forget some lines are not re-usable...there are special drag torques...and by the book, you have to turn the crank to certain positions to torque the rocker base.

order extra clips becuase the ones they ship now will break.

when you re-install the fuel lines to the injectors...connect the line to the injector first and snug it down...then put it close to position to the fuel rail....but squirt some fuel into the lines before torquing...this helps with injector lube and air control. if the injectors dry up...you going to have a hell of a time starting the engine.

dont go WOT right away when fully re-assembled....unless you have all the special tools..its going to take a few on off cycles to get all the air out of the cooling system.

 

Thank you speakerfritz. So far it has taken me about a day to get where I am. No cab lift yet. I got everything out of the way and have the valve covers off on both sides.

I had one rocker laying in the head on the passenger side. The driver side rockers are all in place. But I think I will change all of them to be safe. Did you do lifters and how can you check those for damage without pulling heads?

So as of today I had a contribution code on cylinder 1 which had the broker rocker. But I also have that code on 2 and 8 with no obvious rocker issue. Do you know if the tips are worn enough will they also throw a code or am I looking at bad injectors? This is all assuming the compression test goes ok when I get the adapter to perform the test.

 

I could not do the lifters...did not want to pull the heads and did not want to pull the engine.

my thoughts were if I am going to disassemble down to the point where I can replace 1 rocker, might as well do them all.

with that many contribution codes...me thinks you have a lot of bent push rods.

if all you have is coking on the injectors, that will clean up...but if they are worn...your going to have to go back in there again. so since you have 250K miles.....I would pull and have them tested. my truck only had 87 K when I did my rockers and I was very nervous about not doing injectors.

the next time I have an engine problem...engine is coming out and Im going to rebuild it.

those lifters keep me up at night.....grrrr

check your saddles....your going to see the wear spot and if its too deep...your going to need new saddles.

 

I have been pricing the rockers. I am seeing around $60 for a rocker pair or $175-190ish for a set with the base. What am I missing? It is cheaper to purchase the entire set with base than 4 pairs.

 

 

Quick update. Trying to work when is it above 10. Speakerfritz, did you compression test every cylinder? I cannot remember.

No compression on 1 but that is the one with the intake rocker off. I need to put that back on to do a compression test correct. Others are around 340 but cylinder 2 is 300. Could that be work rockers or an indication of something worse. Have not checked all of them yet.