Piston with the exact design of one of the valves stamped in the top of it?

AJAE

MEMBER
2008 FORD F-250
6.4L
V8
TURBO
4WD
AUTOMATIC
220,000 MILES

In the middle of replacing lifters due to a tapping sound in the driver rear of the engine I came across a piston with the exact design of one of the valves stamped in the top of it. It doesn't appear to be damaged and as far as I know it is seating fine truck ran great. What would cause this? The lifters and cam lobes are still like new. The rocker assembly is getting replaced but it wasn't that bad. Could the valve spring tension be weak causing it to not lift the valve at the proper time/speed?

Monday, May 8th, 2023 AT 2:59 AM

2 Replies

KEN L

MASTER CERTIFIED MECHANIC
51,710 POSTS

The pistons have valve reliefs molded into the piston design so you might be okay. Can you upload an image of what you are seeing so I can tell what's going on? You may have a broken valve spring which can cause a connect issue. I would use a flashlight to see if any valve spring coils are broken.

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Monday, May 8th, 2023 AT 4:42 PM

AJAE

MEMBER
2 POSTS

Sorry for the delayed response, this is where it slapped the piston. I just received new HD springs for this head, and I was going to replace that 1 valve. All new mahle lifters but I tell ya these mahle lifters are in not much better shape then the ones that come out of the engine. The one think I noticed was that I could blow with my mouth enough air pressure through the bottom of the new hydraulic lifters to open the check valve in it, I couldn't do that even with a pressurized can of brake cleaner.

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