6.4 Rebuild - Valvetrain Movement ('Lift') - Very Little

[MS1]

RE: 2008 F-250 6.4 (215k, Job 1)

I'm in the midst of rebuilding - or more so 'Replacing', the top end of my 2008 6.4. I have installed the new valvetrain components on new KDD Cylinder Heads (Stage 2, 100 lb Valve Springs). Everything torqued to spec (did rockers first) but when I hand crank the engine the pushrods only 'snug-up' to the rocker arms. The rocker arms themselves do not discernably move or compress the valve springs. The top of the rockers are essentially flush across the head. I HAVE checked the cam through the block and the lobes look good, at least to my to my relatively untrained eye.

• Did I miss a step?
• Do I need to Compress the valve springs for the install?
• IS this normal (???)

Common sense would tell me that the replacement pushrods are too short, but that seems to be the route even Ford has gone with the 6.4 pushrods.

Here are the components I'm using (All are New Parts):

• KDD Heads w/Stage 2, 100lb Valve Springs[/URL]
• Elgin Industries Hydraulic Roller Lifters (HL-2201S)
• RCD Chromoly Pushrods, .080 Wall (Replacing the 3/8" longer OEM w/balls on the ends)
• OEM Rocker Arms and Valve Bridges

Any insight or thoughts would be greatly appreciated as this is my work truck - and only vehicle, so I've really gotta get this Sucker back on the road, but I can't continue until I get this figured out. Thank You!



*Genesis for Rebuild - I had what I thought to be a stuck injector, turned out to be a broken rocker arm. Decided to put the time/money into it, as the truck has been fantastic for 50k+ miles even with somewhat regular heavy towing use and is already otherwise 'set-up' for my work.

 

[sootie]

What is there to figure out? The lifters are hydraulic. You won't see proper operation unless the engine has full oil pressure

 

[webb06]

Lifters need oil as sootie said.


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[Bgdiesel]

I have to disagree with both you guys, the rockers will actuate and the valves will open without oil in the lifters, not fully but will obviously cycle up and down... if you read what he said, he said no movement whatsoever and you guys have got to know that there is no need for a drastically shorter pushrod like that on a 6.4 engine and the updates shorter pushrod from ford is only shorter compared to what came on the 6.0, not the 6.4 engine, it is what always came in 6.4'a because the cam is .050" higher in the block compared to the 6.0 block design... in summary you have way to short of a pushrod


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[powerstrokeboss]

What he said
Even with dry lifters, the rocker should compress the spring somewhat.
Pushrods are too short

 

[Sixfoh]

Yup just did a 6.4 rebuild and torqued to the book specs. Requiring only half be torqued then the motor turned 180 degrees and the others torqued etc. All of my components snugged up and were not loose as you describe. Also used KDD heads. Also might be worth while I soaked my lifters for about a day. Although they werent completely "full" I find it good practice to soak some of these valve train parts. And satisfying to watch them bleed out air bubbles LOL

 

[webb06]

I have to disagree with both you guys, the rockers will actuate and the valves will open without oil in the lifters, not fully but will obviously cycle up and down... if you read what he said, he said no movement whatsoever and you guys have got to know that there is no need for a drastically shorter pushrod like that on a 6.4 engine and the updates shorter pushrod from ford is only shorter compared to what came on the 6.0, not the 6.4 engine, it is what always came in 6.4'a because the cam is .050" higher in the block compared to the 6.0 block design... in summary you have way to short of a pushrod


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I’ve pulled apart many early build 6.4 engines that have the same length pushrod as 6.0.

Still think the lifters need oil to bring up the slack. Why would RCD mass produce a pushrod that is too short? Those guys know what they’re doing.


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[StrokiNDieseL]

I’ve pulled apart many early build 6.4 engines that have the same length pushrod as 6.0.

Still think the lifters need oil to bring up the slack. Why would RCD mass produce a pushrod that is too short? Those guys know what they’re doing.


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I just followed these guys recommendations of just in/out & torque to specs using rcd replacement and all went snug. Just rockers/pushrod replacement here tho for now.