Compression Ignition Addict
Join Date: Feb 2008
Location: Jersey Shore (Not Seaside!)
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The thumping of the intake is a result of a valve not fully opening. In long service its a characteristic of a failed lifter. It can also happen if the bridge was not installed correctly, a pushrod is bent, internal lifter leak or not filling with oil. It also happens as it did for me if the lifter drains down and takes some time to be refilled by oil pressure after a long sitting period.
With the Colt Stage 2 cam, was the piston to valve clearance checked? Valve recession depths?
Former Vehicle Test Manager, Friction Products.
03 F350SC 4x4 6.0 Auto 5/30/03
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