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Had a choice between a timing chain kit and a full head rebuild on my F-150
I was fixing a 2014 F-150 with the 3.5 EcoBoost that had jumped timing. I figured I could just swap the timing chain kit for about $400 and call it a day. But after pulling the cover off, I saw the passenger side chain guide had broken apart and sent plastic chunks through the oil passages. My gut said just do the chain kit and flush the oil system, but my buddy who runs a shop in Phoenix talked me into pulling both heads for a full rebuild. It cost me around $2800 in parts and a solid weekend of work. Ended up finding two bent exhaust valves on the driver side that would have trashed the new chain in a month. Has anyone else torn into an EcoBoost and found hidden damage like that after a timing skip?
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claire_ramirez1mo ago
Read on a Ford forum that EcoBoost timing slips often hide valve damage that way.
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patriciareed1mo ago
Claire's right about that. Those EcoBoost motors are REAL sensitive to timing skips because of the interference design. I've seen three different builds where a skipped chain bent valves but the heads still sealed on the compression test. You gotta pull the heads to see the witness marks on the pistons or catch those slightly bent exhaust valves that hang up just enough to snap a guide later. The plastic guide debris is the KILLER though, it gets into the VCT solenoids and oil control valves even after you flush it once or twice.
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