How to tell if a valve is burnt IN A 4.6 FORD F150?

How to tell if a valve is burnt IN A 4.6 FORD F150?

Ways to tell if there's a burnt valve is blue smoke coming out the exhaust as it has an oil smell to it. Other ways to tell there's a burnt valve is to pull the spark plugs and disable the ignition and perform a compression test. If the results are low in a certain cylinder a leak down test is required as burnt intake valves lets air leak through the throttle body burnt exhaust valves lets air through the exhaust. To replace the burnt valves the cylinder head has to be pulled and valve compression tools would have to be rented as you have to compress the valve spring to undo the locks to pull the valve. At the same time since you have the engine apart you have the opportunity to inspect the timing chain and tensor and replace if there's slack.

COMPRESSIO0N TEST TELL YOU COMPRESSION IS LOW BUT ONE NEEDS TO DO MORE TO KNOW WHY.
a COMPRESSOR AND A HOSE AND A REGULATOR IS NEEDED. PLACE THE CYLINDER IN QUESTION AT TOP DEAD CENTER. REMOVE THE SPARK PLUG AND INSTALL A NIPPLE. ATTACH AN AIR HOSE WITH PRESSURE REGULATED TO 40 OR 50 psi
NOW LISTEN… IF AN EXHAUST VALVE IS BURNT YOU WILL HEAR THE AIR ESCAPING OUT THE EXHAUST PIPE. IF AN INTAKE VALVE IS BURNT YOU WILL HEAR THE AIR IN THE INTAKE MANIFOLD VIA THE THROTTLE BODY OR CARBURETOR.
NOTE A LEAK DOWN TESTER DOES All THIS FOR YOU AND IN ADDITION TELLS YOU THE PERCENTAGE OF LEAKDOWN!
RETIRED ASE MASTER TECHNICIAN
THATS WHAT THE PRO WOULD DO…

Run a Compression test.

Compression test.

A compression test.

Pretty much have to pull a head. And, with the overhead cam chains involved, that is a job.

Pull the spark plugs and run a compression test

Without spending money you can pull each spark plug wire one at a time and listen to the engine. If you hear the engine change pitch or run rough or start missing, that particular cylinder is good. If when you pull the wire you hear no change that cylinder is probably bad.
Another method is to take a long steel rod or perhaps the tire iron and place your thumb on the top of the other end, or the nut end. Place the other end of the rod against the top of the head below the cover on each cylinder and put your thumb knuckle in your ear. Go from cylinder to cylinder listening and the bad valve will make an obvious, different noise. Hard to describe, Like a hard clicking or metallic sound. It'll be obvious.