Has anyone read the July 2025 issue of MCA’s Mustang Times about the 4.6l 3v engine by Jim Smart? Very scary. Jim notes a number of issues attributed to the 3v engine specifically, including but not limited to the timing chain/(plastic) guides, insufficient oiling, oil pressure, etc.
I have a 2008 Shelby GT-C with 12k miles and have had no issues. Has anyone experienced any engine malfunction? What kind of oil is recommended? What preventative maintenance should be done?
Help me feel better about the future of my modular 4.6l, 3v engine. Thank you.
There only thing scary and even then, only for little children and old ladies, about the 4.6 3V engine is the soundtrack once you get into that 3500-6500rpm sweet spot!
The internet is notorious for exaggerating its flaws. No engine is without them but the 3V will go past 300k miles with proper care and maintenance. So what are its flaws?
1. Cam phasers. Known to fail if the engine spends extended periods close to the rev limiter. Phaser knock in itself isn't catastrophic but it'll cause driveability problems due to over-retarded cam timing.
2. Timing chain tensioners. High mileage and age will eventually cause the gaskets to leak, resulting in a slack timing chain that will eat through the guides and break them. I recommend replacing the whole timing set at 150k miles.
3. Cam followers. The original ones can experience oiling problems with the roller bearings, eventually causing them to seize. If that happens, you'll hear a noticeable tapping sound under the valve cover as the seized cam follower begins to eat into the corresponding cam lobe. Do not neglect if that happens. Ford Performance released updated cam followers after the engine went out of production.
4. Oil pump. The stock unit is reliable and durable but extended high rpm use can cause the aluminium backplate to flex, resulting in a drop in oil pressure. The 13/14 GT500 oil pump is a direct swap and has a steel backplate that solves this problem. You could swap in billet oil pump gears to make it completely bulletproof.
5. Connecting rods. The stock powdered metal units are fine in N/A and mildly boosted applications but anything over 450rwtq is flirting with the risk of bending or breaking them. The Gen 2/3 Coyote OEM forged rods are an inexpensive upgrade and are rated up to 700hp. Otherwise go for a set of forged H beam rods.
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