Flat tappet cam failure
Thread Starter
Intermediate
Joined: Sep 2007
Posts: 34
Likes: 0
Flat tappet cam failure
Anybody experience a quick cam failure? Got about 4 hours run time on my rebuilt motor with flat tappets and I've got alot of noise somewhere. Definitely not the power stuff on front of the motor, I've pulled off the alt,power steering pump and a/c compressor. Almost sounds like a rod knock, but can't really tell. Motors out of warranty by about 6 weeks too. Seems to run fine with little noise at start up but gets worse when things warm up, about 5 minutes. Could this be the dreaded premature flat tappet cam failure? Got the right break in oil in it too.
Le Mans Master
Joined: Sep 2000
Posts: 9,078
Likes: 7
From: DFW TX
Cruise-In VII Veteran
St. Jude Donor '07
Have you pull the valve covers to check for a loose rocker? Check the easy stuff first, before you panic. One of my lifters didn't pump up and it made all kind of noise. One push down on the rocker and it pumped up, problem solved.
Drifting
Joined: Apr 2007
Posts: 1,970
Likes: 45
From: Cameron Park CA
An easy test for a wiped cam lobe is to take the valve covers off and start the engine. The pushrods should all be rotating. Any that are not rotating indicate that cam lobe is bad.
Lifters are not perfectly flat on the bottom, they are ground with a slight concave surface. The cam lobes are tapered very slightly also, so the edge of each lifter rides on the high side of the taper, resulting in the lifter rotating. It's done on purpose so there is not a pure sliding interface between the lifter and cam lobe, but more of a rotating one so wear is much less.
Lifters are not perfectly flat on the bottom, they are ground with a slight concave surface. The cam lobes are tapered very slightly also, so the edge of each lifter rides on the high side of the taper, resulting in the lifter rotating. It's done on purpose so there is not a pure sliding interface between the lifter and cam lobe, but more of a rotating one so wear is much less.
Corvette Stories
The Best of Corvette for Corvette Enthusiasts
Top 10 Most Explosive Corvettes Ever Made: Power-to-Weight Ratio Ranked!
Joe Kucinski
150 hp to 1,250 hp: Every Corvette Generation Compared by the Specs That Matter
Joe Kucinski
8 Coolest Corvette Pace Cars (and Replicas) of All Time
Verdad Gallardo
Top 10 Corvette Engines RANKED by Peak Torque (70+ Years of Muscle!)
Joe Kucinski
Corvette ZR1X Will Be Pacing the Indy 500, And Could Probably Race, Too!
Verdad Gallardo
Top 10 Corvettes Coming to Mecum Indy 2026!
Brett Foote
Top 10 C9 Corvette MUST-HAVES to Fix These C8 Generation Flaws!
Michael S. Palmer
10 Revolutionary 'Corvette Firsts' Most People Don't Know
Joe Kucinski
