Filters
16 products
Not sure it fits your truck?
Our Wildwood, FL techs will confirm the right part for your build before you buy.
Call or Text (352) 722-5295Valve train on the 2008-2010 Ford 6.4L Powerstroke
The 6.4L is a cam-in-block pushrod V8 with a gear-driven camshaft and four valves per cylinder, 32 in all. The valve train is hydraulic lifters, pushrods, rocker arms on fulcrum plates and valve bridges. Each fulcrum plate bolts through the rocker pedestal into the head with two bolts, and unlike the 6.0L, the head bolts do not retain the rocker carrier. The only oil the rockers get arrives through the pushrods, which makes oil quality a valve train issue on this engine. The heads can support about 900 rwhp with stiffer valve springs and stronger pushrods. See the full Ford diesel lineup in our Powerstroke collection.
What fails and why
Oil is the root of it. Fuel-diluted oil chews up rocker tips and bridge balls, and the 16 hydraulic lifters are damaged by diluted oil too. The fuel gets in from regeneration cycles and from leaking piezo injector bodies. Lower in the engine, the factory cast pistons crack at the re-entrant bowl lip, and a stuck-open injector nozzle can over-fuel a cylinder and torch a piston. One cracked piston is usually found whenever a 6.4L is torn down. MAHLE pistons and rings are in this collection too.
Stock replacement vs. upgrade
For rocker lubrication complaints, updated pushrods with larger oil holes and high-quality CJ-4 oil are cited as the fix. When you build for power, the path is upgraded valve springs and pushrods with cryogenically treated rocker arms, and worn rockers and bridges get replaced as a set. For pistons, the MaxxForce 7 industrial piston, with a de-lipped bowl and thicker crown, is the usual replacement for cracked factory pistons; forged pistons are for high-horsepower builds. If you are rebuilding to stock spec, MAHLE's intake and exhaust valves and standard pistons with rings cover it. Whatever you install, keep oil changes at 5,000 miles, the shop consensus interval for the 6.4L because of dilution.
What we carry
XDP supplies the performance side: the XD388 HD high-boost valve spring set, the XD382 HD billet rocker arm valve bridge set and XD320 Street Performance pushrods. MAHLE covers the 211-4521 intake valve and 211-4522 exhaust valve, plus pistons with rings (224-3666WR, 224-3953WR reduced compression and 224-3851WR Maxx Force 7) and standard and .020 piston ring sets. Gator Fasteners hardware rounds it out.
Fitment notes
The XDP valve spring set and pushrods are listed for 2003-2010 6.0L and 6.4L, while the XD382 bridge set, the MAHLE valves and the MAHLE pistons are listed for 2008-2010 6.4L only. Pistons come in standard and .25 mm, .50 mm and .75 mm oversizes depending on the design, and ring sets in standard and .020, so order to what your machinist measured. The XD320 pushrods are 11/32 inch. Read the fitment line on every product and verify by VIN.
Frequently asked questions
Why are the rocker arms wearing on my 6.4L?
The rockers get oil only through the pushrods, and when the oil is thinned by fuel, the rocker tips and bridge balls wear. Change oil every 5,000 miles and check the dipstick weekly for a rising level. Updated pushrods with larger oil holes and good CJ-4 oil are the cited fix for lubrication complaints.
Should I replace rockers and bridges one at a time?
No. Replace worn rockers and bridges as a set. If one is chewed up from diluted oil, the rest have been running on the same oil.
What is a Maxx Force 7 piston?
MaxxForce 7 is Navistar's name for the same engine in International trucks. Its industrial piston has a de-lipped bowl and thicker crown and is the usual replacement for cracked 6.4L pistons. MAHLE's 224-3851WR Maxx Force 7 pistons with rings are here in .25 mm, .50 mm and .75 mm sizes.
Do I need stiffer valve springs?
Stiffer springs and stronger pushrods are what let the 6.4L heads support about 900 rwhp, so they belong on the build list when you are adding power. For a stock rebuild, match the parts to the factory spec.
Not sure what fits? Call the shop at the number in the header, or use the fitment checker on any product page. We install everything we sell.