Lifter Tick??? (Solved)

[dmevans]

My engine has always made this ticking sound. The plane is idling at roughly 900rpm. Is this the appropriate frequency for lifter tick? Most mechanics are scratching their heads as well.

The engine has approximately 300 hours on it.

Dry tappet clearance measures as follows:

Cylinder 2 Intake: .061
Cylinder 2 Exhaust: .060

Cylinder 4 Intake: .047
Cylinder 4 Exhaust: .052

I also replaced the exhaust gaskets as well. My only other option would be to replace all of the hydraulic plungers on that side… 

Let me know if you’ve experienced this noise before. Thanks everyone!!

 

[A64Pilot]

Use a mechanics stethoscope or large screwdriver to find source of sound.

‘It sounds like it could be a arcing plug wire maybe, or exhaust leak.

But I’d also pull the pushrods and make sure none are bent, if you find a bent one, it’s most likely from a sticking valve, but a bent pushrod should show up as excessive clearance. 

[RLCarter]

Had a Continental 0-300 that sounded like that... was an impulse coupler on one of the mags that wouldn’t release after start up, but I don’t think you have an impulse coupler. Sounds to “Clanky” to me, valves usually are more of a ticking sound

[carusoam]

If you hear...  tic, tic, tic, tac, tic, tic, tic, tac...

One of the four valve trains is not like the others...

Oddly, i don’t hear one that is different...
 

But, when you put your hand over one of the valve covers...  did that muffle the sound?

That is funky...

See if @M20Doc hears anything odd with that? (Loud ticking sound near the valve cover of an IO360 at idle)

PP thoughts only, not a mechanic...

Best regards,

-a-

[N201MKTurbo]

It makes a mess, but run it with the valve cover off so you can watch and feel the rockers as they work. You might have a bad plunger.

[Guest]

Years ago I remember hearing of a Lycoming engine that had an internal oil supply issue whereby the left bank oil supply was low.  The engine was run with the oil return line plumbed into 4 separate containers to measure the oil flow.  Lycoming had to repair/ replace the engine.

Clarence

[takair]

Does it sound different when approaching from the right side?  Does it go away with RPM?  Do you hear this in the cockpit too?  Exhaust leak would be easy to find....any grey around the gaskets or slip joints?  

[A64Pilot]

1 hour ago, M20Doc said:

Years ago I remember hearing of a Lycoming engine that had an internal oil supply issue whereby the left bank oil supply was low.  The engine was run with the oil return line plumbed into 4 separate containers to measure the oil flow.  Lycoming had to repair/ replace the engine.

Clarence

I’ve done that and was surprised at how little the oil flow there is.

There is a theory, probably a good one too that low oil flow causes wear of the exhaust valves for lack of cooling and lubrication.

Bad lifter you should be able to find with a big screwdriver. For those that haven’t tried it, place the tip on the engine and the plastic handle in your ear, it will conduct the sound through the screwdriver, of course a mechanic stethoscope is probably better, never had one myself. 

Edited June 1, 2021 by A64Pilot

[flyingchump]

23 hours ago, A64Pilot said:

 

Bad lifter you should be able to find with a big screwdriver. For those that haven’t tried it, place the tip on the engine and the plastic handle in your ear, it will conduct the sound through the screwdriver, of course a mechanic stethoscope is probably better, never had one myself. 

The screwdriver trick works but this is better.  I bought one years ago and have use it for all sorts of problem solving.  Airplane, cars, motorcycles, even plumbing.

https://www.amazon.com/Lisle-52500-Mechanics-Stethoscope/dp/B0002SQYSM

[Shiny moose]

1 hour ago, flyingchump said:

The screwdriver trick works but this is better.  I bought one years ago and have use it for all sorts of problem solving.  Airplane, cars, motorcycles, even plumbing.

https://www.amazon.com/Lisle-52500-Mechanics-Stethoscope/dp/B0002SQYSM

I have own a few of those, I sure wish the quality was a little better as I seem to break them.

 

[flyingchump]

1 hour ago, Shiny moose said:

I have own a few of those, I sure wish the quality was a little better as I seem to break them.

 

There are tons of them out there.  Many are poor quality and some are not.  Even if you consider these disposable, $15 is a pretty cheap cost for diagnosing our engines. 

I don't know the brand but the one I have has lasted me 20+ years so far.

[dmevans]

On 5/31/2021 at 9:29 PM, carusoam said:

If you hear...  tic, tic, tic, tac, tic, tic, tic, tac...

One of the four valve trains is not like the others...

Oddly, i don’t hear one that is different...
 

But, when you put your hand over one of the valve covers...  did that muffle the sound?

That is funky...

See if @M20Doc hears anything odd with that? (Loud ticking sound near the valve cover of an IO360 at idle)

PP thoughts only, not a mechanic...

Best regards,

-a-

 

The number 4 cylinder is the culprit. When I used a mechanics stethoscope, I could hear the tapping/clanging sound pretty loud through the valve cover. All of the other cylinders sounded normal…

 

On 6/1/2021 at 5:23 AM, M20Doc said:

Years ago I remember hearing of a Lycoming engine that had an internal oil supply issue whereby the left bank oil supply was low.  The engine was run with the oil return line plumbed into 4 separate containers to measure the oil flow.  Lycoming had to repair/ replace the engine.

Clarence

This is interesting Doc. I may take a look into this. Compressions and temps are all good, but this noise is driving me crazy!

I have also ordered 2 new plungers to cover that base as well. Would weak or broken valve springs cause this noise? 

[N201MKTurbo]

5 hours ago, dmevans said:

 

The number 4 cylinder is the culprit. When I used a mechanics stethoscope, I could hear the tapping/clanging sound pretty loud through the valve cover. All of the other cylinders sounded normal…

 

This is interesting Doc. I may take a look into this. Compressions and temps are all good, but this noise is driving me crazy!

I have also ordered 2 new plungers to cover that base as well. Would weak or broken valve springs cause this noise? 

Take the valve cover off and look. It only takes 5 minutes.

I had a broken valve spring and had no idea it was broken until I removed the cylinder for other reasons. The valves have two springs, one was broken.

[A64Pilot]

Put the cyl on TDC compression. and see how much play the rockers have, if one feels excessive, pull the pushrod and roll it on something flat to see if it’s bent.

Assuming you have flat tappets, you do know what’s involved in changing them?

[dmevans]

4 hours ago, N201MKTurbo said:

Take the valve cover off and look. It only takes 5 minutes.

I had a broken valve spring and had no idea it was broken until I removed the cylinder for other reasons. The valves have two springs, one was broken.

I checked the valve springs this morning. They seem to be pretty stiff with the cylinder at TDC on the compression stroke. The inner and outer springs seem to be intact. 

[dmevans]

4 hours ago, A64Pilot said:

Put the cyl on TDC compression. and see how much play the rockers have, if one feels excessive, pull the pushrod and roll it on something flat to see if it’s bent.

Assuming you have flat tappets, you do know what’s involved in changing them?

All of the push rods are true and straight. 

[A64Pilot]

With everything together and the cylinder at TDC compression, is one of the rockers arms loose, have excess play indicating a collapsed lifter?

How many hours on this engine, when did it start making this noise? Did it start quieter and been getting louder?

If you can’t find anything, I’d pull the cylinder. look at the wrist pin etc. I’d have to find the source of that noise, I wouldn’t fly it until I did.

[Guest]

5 hours ago, dmevans said:

I checked the valve springs this morning. They seem to be pretty stiff with the cylinder at TDC on the compression stroke. The inner and outer springs seem to be intact. 

I asked Ron Poelstra of Reliable Horse Power, he suggests pulling the hydraulic units out of the tappets to test them for a bad check valve or loose fit to the tappet bore.  He also says the best part number is 78290.

Clarence

[Culver LFA]

49 minutes ago, M20Doc said:

I asked Ron Poelstra of Reliable Horse Power, he suggests pulling the hydraulic units out of the tappets to test them for a bad check valve or loose fit to the tappet bore.  He also says the best part number is 78290.

Clarence

Clarence - Please say Hello to Ron and let him know that IO-360 I bought from him 2 year ago is running great.  He builds a smooth and powerful engine!

[carusoam]

Nice pireps for Ron Poelstra...

In case somebody comes looking...

Best regards,

-a-

[dmevans]

54 minutes ago, M20Doc said:

I asked Ron Poelstra of Reliable Horse Power, he suggests pulling the hydraulic units out of the tappets to test them for a bad check valve or loose fit to the tappet bore.  He also says the best part number is 78290.

Clarence

Clarence,

My plungers just came in. Gonna throw them in tonight and hope for the best! Fingers crossed!

 

[carusoam]

Great pic DM!

with the part number right on it.

Best regards,

-a-

[takair]

14 hours ago, dmevans said:

Clarence,

My plungers just came in. Gonna throw them in tonight and hope for the best! Fingers crossed!

 

Do you check the dry clearances?  Not sure it’s required, but It might be worth doing in case the old ones had wear or different tolerances.  

[dmevans]

Okay here’s the verdict!

I removed all of the valve springs on cylinders 2 and 4.  When everything was laid out on my work table everything appeared to be normal. There were no cracked or weak springs and no signs of abnormal wear.

When I went to reinstall all of the springs is where things started to get interesting. When I installed the intake valve spring on cylinder 4, I noticed there was a huge gap (2-3mm) between the intake valve keys. 

It appears that whomever overhauled the cylinders used an upper EXHAUST valve seat on the INTAKE valve. The center diameter of the exhaust valve seat is much larger than the intake seat. This caused the valve keys to jump around freely and cause excessive play in the intake portion of the valve train.

I installed the new intake valve seat and the engine is quiet and smooth. 

Thank you guys for all of the help and insightful replies! 

[N201MKTurbo]

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