Is tapping sound likely a broken valve spring?

[SyberTiger]

I hear a tapping sound when the engine is idling at a frequency of 4 or 5 taps per second. Is this likely a broken valve spring on one of the cylinders and does the frequency seem correct given the engine RPM is about 700.

To me it sounds like a valve lifter issue you'd hear on an 1970's engine. But, I wonder if this is really a timing chain tensioner/rail issue.

 

[TechGuru]

Probably a collapsed hydraulic lifter. See if it goes away after a oil change and 100 miles of driving.

Are you using 5W-30 (err I see you have the V8, in that case 5W-20).

 

[SyberTiger]

Probably a collapsed hydraulic lifter. See if it goes away after a oil change and 100 miles of driving.

Are you using 5W-30 (err I see you have the V8, in that case 5W-20).

I change the oil religiously every 3,000 miles with Motorcraft 5w-20 synthetic blend. The tapping sound has been present for the last few years.

 

[Number4]

I thought I had a bad roller, having researched the Mustang threads. But 98% positive it's my torque converter. It made that tapping sound for a long time. Now it's progressed. Can't find the thread on it, but I suspect if I drop my pan the filter will be covered in metal shavings. Just an idea.

 

[SyberTiger]

How do you inspect and detect a collapsed lifter? Just grab a hold of each one and see how much play there is?

 

[imp]

@SyberTiger
Broken valve springs mean broken valves and/or pistons. You might isolate the noise area with a stethoscope. Lifter noise should be discernible by listening to the underside of the oil pan. Torque Converter noise should be more pronounced on the flywheel housing.

I use a long screwdriver, press the round handle end against my ear to close the opening, while touching the blade to suspected noise producers. This method ruled out rear axle noise suspected as from center section, but definitely told me it was a wheel bearing. imp

 

[SyberTiger]

@SyberTiger
Broken valve springs mean broken valves and/or pistons. You might isolate the noise area with a stethoscope. Lifter noise should be discernible by listening to the underside of the oil pan. Torque Converter noise should be more pronounced on the flywheel housing.

I use a long screwdriver, press the round handle end against my ear to close the opening, while touching the blade to suspected noise producers. This method ruled out rear axle noise suspected as from center section, but definitely told me it was a wheel bearing. imp

Yup, I use the giant screwdriver trick too for listening. I already have the engine partially torn down and the valve covers off so I can't listen to them now. I have yet to take a close look at each valve spring and lash adjuster but when I climb in close I wanted to know what I'm looking for. There might not be anything wrong at all but the ticking sound to me was like an old engine that has adjustable rocker arm clearances. Maybe the ticking sound is the timing chain tensioner arms.

 

[TechGuru]

I thought I had a bad roller, having researched the Mustang threads. But 98% positive it's my torque converter. It made that tapping sound for a long time. Now it's progressed. Can't find the thread on it, but I suspect if I drop my pan the filter will be covered in metal shavings. Just an idea.

I have that TC tap, but it randomly comes and goes...

 

[imp]

I have that tap, but it randomly comes and goes...

@TechGuru
Almost always, IMO, valve lifter noise. They maintain "zero clearance", whether OHV, or OHC, by using a "cushion" of trapped oil which must withstand the force of opening the valve. If that "cushion" is temporarily lost, usually due to a small particle of dirt blocking off the hole which admits oil into the chamber, and as operation continues, the trapped cushion slowly finds it's way out, due to normal clearances in the lifter. Then it rattles like the old-time solid lifters. Hydraulics have usually around 1/8 to 3/16 of an inch of "cushion", so if completely "collapsed", quite a loud racket is made. That's rare; the ticking noise is likely due to only a few thousandths, maybe 10 or 20, of an inch clearance. imp

 

[SyberTiger]

@TechGuru
Almost always, IMO, valve lifter noise. They maintain "zero clearance", whether OHV, or OHC, by using a "cushion" of trapped oil which must withstand the force of opening the valve. If that "cushion" is temporarily lost, usually due to a small particle of dirt blocking off the hole which admits oil into the chamber, and as operation continues, the trapped cushion slowly finds it's way out, due to normal clearances in the lifter. Then it rattles like the old-time solid lifters. Hydraulics have usually around 1/8 to 3/16 of an inch of "cushion", so if completely "collapsed", quite a loud racket is made. That's rare; the ticking noise is likely due to only a few thousandths, maybe 10 or 20, of an inch clearance. imp

Will a collapse lash adjuster look obvious as compare to the other ones just looking around under the the valve covers?