56 lifter tap intermittent and irregular? (only 400 miles on 2017 engine rebuild)

[klogsdonjr]

Just started experiencing a metallic tap when letting off gas or starting to move from stand still. One mechanic said it sounded like a lifter issue. The thing is it's not a constant tap tap tap ticking. It's pretty random in frequency and does down when at standstill. It's like a tap tap ... tap ..... tap tap tap .......tap, totally irregular. Then I might hear it once every 20 seconds or so when idle. Hear it most when starting to move and when letting off the gas while moving. I've got a shop appointment next wednesday. Obviously I'm not driving it till then.

Any similar experiences or thoughts?

[ICON 1956]

What grade of octane gas are you using ?

[klogsdonjr]

I've been switching between hi and lo. This tank is lo. But never heard this before with previous lo-test tanks. Oil and filter was also changed 2 weeks back, using rotella t4 15x40.

[Joe Johnston]

How long since your lifters have been adjusted?

[klogsdonjr]

joe - i should have added (and now have on the title) the engine was rebuilt in 2017. only about 100 miles on it till i acquired it mid-summer. ive put about 300 miles on it since then. to my knowledge it hasnt been touched since 2017.

the intermittent sound is what gets me - wouldnt a lifter than needed adjustment be pinging constantly? and at all speeds?

[Joe Johnston]

With only 400 miles I would definitely check the lifter adjustment. Often needs to be done after a rebuild and a few miles. Easy to do and may only cost a couple of gaskets - maybe not even that. Once done, no need to question that simple part of the diagnostics.

[MarkR]

I agree with Joe. Eliminate the lifters first. Especially on a low mileage rebuild.
Mark
Las Vegas

[Joe Johnston]

AFTER adjusting the lifters, re-torque EVERYTHING! Head bolts, Intake bolts, Exh Manifold Bolts. A few heat cycles and many years of neglect require going over everything. This costs nothing but time and a bit of energy. Don't start throwing money and parts at it hoping something will fix it. Systematically diagnose and evaluate.

[DynoDan’55]

Just started experiencing a metallic tap when letting off gas or starting to move from stand still. One mechanic said it sounded like a lifter issue. The thing is it's not a constant tap tap tap ticking. It's pretty random in frequency and does down when at standstill. It's like a tap tap ... tap ..... tap tap tap .......tap, totally irregular. Then I might hear it once every 20 seconds or so when idle. Hear it most when starting to move and when letting off the gas while moving. I've got a shop appointment next wednesday. Obviously I'm not driving it till then.

Any similar experiences or thoughts?

Do you have exhaust manifold gaskets? Exhaust leak ticks can easily be mistaken for lifter noise. You can have the manifolds & heads planed, but gaskets are cheaper (assuming you don’t break off a manifold ear by unequal torquing). Also, I like locking manifold bolts. ‘Set them & forget them’.

[thessler]

I second the exhost manifold leak, I have heard it sound like a tap. I not sure this is correct but I have read in more than one place that these engines don't use exhost manifold gaskets it's just metal to metal. I have had one loosen up a very little and sure enough sounds like a tap. If you do re tighten your manifolds it is my understanding if it has a gasket that is when the ear will snap off. I am not an authority on this , do your own research.
I would also agree to readjust the valves , it's not your problem but it should be done on a new motor. After everything settles in they will tend to go out a bit.
Good luck , Tom

[klogsdonjr]

Appreciate all the guidance! Will be sure to lay out a list and run through it in order.

[voltron]

The spring on the heat riser on the passenger side exhaust manifold broke on my car and it was flopping back and forth from the exhaust pulses making a klinking sound.

[55blacktie]

No exhaust manifold gaskets.

[klogsdonjr]

So my neighbor mechanic gave it a listen, and a test drive. We started out and he agreed it might be exhaust leak, but as the engine warmed and almost back in driveway it worsened and definitely sounded metallic and mechanical. We then surmised some bolt tightening needed on the flexplate or cover. After opening it up all bolts were already tight. One last turn on the wheel and we heard the clanck, now loud this time because we were under the car with covers opened and engine off. He thinks it might be a cracked flexplate and getting worse.

So wed scheduled at the transmission/engine shop sounds like next best move.

[Alan H. Tast]

Did you do ANYTHING related to checking the lifters, rocker arm adjustment and valve lash? Don't ignore what everyone else has posted previous about this. You don't have hydraulic lifters in a Y-block of this vintage and valve train/rocker adjustment is a mandatory part of maintaining the engine. Until you do you're just chasing your tail. Read up on how to do this procedure - do a Google search for Ford Y-block valve train rocker arm adjustment for a better understanding before going further.