My exposure to troubleshooting hydraulic lifters is somewhat limited. I've rebuild a few auto engines that use hydraulic lifters but have never experienced a lifter failure or any other kind of trouble so I'm a noob when it comes to dealing with issues.

Yesterday was I running my engine to check a few things and heard a valve clatter on one side. I pulled to valve covers and found that the valve lash on the center cylinder was huge; within spec for a dry lifter but not tight like it should be when full of oil. The other cylinders were tight until I worked the oil out of the lifters.

Any ideas on possible causes? We only ran the engine for 5 minutes or so and only at idle speeds. Oil pressure was 65psi. Maybe that's not long enough to pump up all the lifters?

I'm going to call the shop that remand the lifters to see what they say but I wanted to see what you guys thought.

What engine?

One with hydraulic lifters[emoji6][emoji16]

But since you asked, it’s a Continental IO360.

whee wrote:One with hydraulic lifters[emoji6][emoji16]

But since you asked, it’s a Continental IO360.

Did you buy all new when you rebuilt it? I don't recall how deep you went on that engine.

Edit: I reread your post and you had them remanufactured. Carry on. I'm curious how one would identify a lemon too. FWIW I purchased all new for my overhaul to the tune of $45 each IIRC.

whee wrote:One with hydraulic lifters[emoji6][emoji16]

But since you asked, it’s a Continental IO360.

[emoji16]

It actually makes a difference.

On that engine, I wouldn’t do anything further until you go fly balls to the wall for at least 1 hour and see if the problem persists.

Italian tune up.

Aryana wrote:

whee wrote:One with hydraulic lifters[emoji6][emoji16]

But since you asked, it’s a Continental IO360.

[emoji16]

It actually makes a difference.

On that engine, I wouldn’t do anything further until you go fly balls to the wall for at least 1 hour and see if the problem persists.

Italian tune up.

I’m unwilling to run it without some kind of determination of the issue. It was loud enough I could hear it while standing next to the plane with my head in the cockpit. And when I stuck my head closer I could tell it was the middle cylinder.

I called the shop and the guy I need to talk to it out until Monday.

Zzz wrote:

whee wrote:One with hydraulic lifters[emoji6][emoji16]

But since you asked, it’s a Continental IO360.

Did you buy all new when you rebuilt it? I don't recall how deep you went on that engine.

Edit: I reread your post and you had them remanufactured. Carry on. I'm curious how one would identify a lemon too. FWIW I purchased all new for my overhaul to the tune of $45 each IIRC.

$45 each?

http://www.aircraft-specialties.com/lifter-658106/

Bagarre wrote:
$45 each?

http://www.aircraft-specialties.com/lifter-658106/

Wow, today I learned. My engine is a Lycoming 540. The plungers look like this and the lifters look like this. Those aren't exact part numbers, I just grabbed examples really quick.

Is the Continental lifter a single unit with the tappet and hydraulic plunger all integrated?

whee wrote:

Aryana wrote:

whee wrote:One with hydraulic lifters[emoji6][emoji16]

But since you asked, it’s a Continental IO360.

[emoji16]

It actually makes a difference.

On that engine, I wouldn’t do anything further until you go fly balls to the wall for at least 1 hour and see if the problem persists.

Italian tune up.

I’m unwilling to run it without some kind of determination of the issue. It was loud enough I could hear it while standing next to the plane with my head in the cockpit. And when I stuck my head closer I could tell it was the middle cylinder.

I called the shop and the guy I need to talk to it out until Monday.

If it’s making proper static rpm within limits, you can go for it. These old design Continentals aren’t for everyone.

Stuck valves, lifters, etc...helps to run these engines hard and often.

I’m with you on...if it bangs, knocks or rattles...it ain’t right. Sounds like a bad check valve/ball. May have a bit of debris...kind of doubt it. Pull the rocker arm and push tube...tube...magnet to pull the plunger. What is the dry lash on an IO360 Continental?


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Zzz wrote:

Bagarre wrote:
$45 each?

http://www.aircraft-specialties.com/lifter-658106/

Wow, today I learned. My engine is a Lycoming 540. The plungers look like this and the lifters look like this. Those aren't exact part numbers, I just grabbed examples really quick.

Is the Continental lifter a single unit with the tappet and hydraulic plunger all integrated?

At least on the IO-360, the lifter is a single unit.


Whee, Your motor is too new to have a stuck valve and all the lifters should pump up after a few seconds (maybe a minute) of running.

When you pushed on the pushrod, was it soft off the bat or did it resist being collapsed?

Maybe some debris plugged the lifter?

Luckily, you can remove the lifters to inspect (and, god forbid, the cam lobes) without splitting the case or pulling the jug.

m_moyle wrote:I’m with you on...if it bangs, knocks or rattles...it ain’t right. Sounds like a bad check valve/ball. May have a bit of debris...kind of doubt it. Pull the rocker arm and push tube...tube...magnet to pull the plunger. What is the dry lash on an IO360 Continental?


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Dry lash is 0.060” to 0.200”.

Bagarre wrote:

Zzz wrote:

Bagarre wrote:
$45 each?

http://www.aircraft-specialties.com/lifter-658106/

Wow, today I learned. My engine is a Lycoming 540. The plungers look like this and the lifters look like this. Those aren't exact part numbers, I just grabbed examples really quick.

Is the Continental lifter a single unit with the tappet and hydraulic plunger all integrated?

At least on the IO-360, the lifter is a single unit.


Whee, Your motor is too new to have a stuck valve and all the lifters should pump up after a few seconds (maybe a minute) of running.

When you pushed on the pushrod, was it soft off the bat or did it resist being collapsed?

Maybe some debris plugged the lifter?

Luckily, you can remove the lifters to inspect (and, god forbid, the cam lobes) without splitting the case or pulling the jug.

Both lifters on the middle cylinder were soft right off the bat which is when I went “uh ho” something isn’t right. But it is possible that my dinkin around with the prop to get the cam in the right position to check them pushed most of the oil out of them.

The clatter is way to loud to consider it normal or acceptable. I’m unwilling to fly a fresh engine with a possible issue on a brand new never flown airplane. The first flight is going to be sporty enough without having to work about this potential issue.


I really appreciate the ideas/thoughts guys.

Grit in a gallery from a rebuilder can lodge in a check valve. I've never had an exceptionally loud tap from even a failed fully compressed lifter though. The tapping was relatively minor. It generally took a stubborn valve to make a lot of noise like what you might be describing, and wiggling the valve stem with the spring compressed with a tool quickly confirmed or excluded it. Those probe stethoscopes work really well to ID the cylinder and individual valve while standing behind the prop while idling.

lesuther wrote:Grit in a gallery from a rebuilder can lodge in a check valve. I've never had an exceptionally loud tap from even a failed fully compressed lifter though. The tapping was relatively minor. It generally took a stubborn valve to make a lot of noise like what you might be describing, and wiggling the valve stem with the spring compressed with a tool quickly confirmed or excluded it. Those probe stethoscopes work really well to ID the cylinder and individual valve while standing behind the prop while idling.

Those probe stethoscopes are pretty cool; much better than the long screwdriver I grew up using for the same purpose.

I'm pretty sure the oil galleys were clean. The machine shop said they cleaned it and I blew compressed air though the ports before the engine went together.

It's possible what I perceive as a loud clatter may be minor or acceptable to someone else. Actually, my dad couldn't even hear it but he's old

I talked though the issue with a trusted acquaintance who makes his living building engines; mostly auto but quite of bit of airplane engine experience. He is confident the issue is not with the lifters but with my dry valve lash. Even though it is within spec this particular cylinder is just under spec. I'll get some longer pushrods and see how it goes.

Thanks for the help guys!

Just remembering about an IA telling me never to use a magnet to remove lifters, something about the potential of causing part of the lifter to become magnetized and causing more problems when metal debris gets trapped not allowing the ball to seat. Anybody else hear of this?? Or is this a tale

Pretty sure it takes time to realign the electrons to cause or have an affect on the ferromagnetic properties of the molecules in hardened steel..and will not maintain that alignment over time... guess a good test would be to use -200 mesh pulverized magnetite..or similar iron particles that have not been exposed to a magnetic source. Another tool or option I’ve used to remove lifters is external “C” snap ring pliers...a well worn tool doesn’t work well as the edges of the pliers need to be fairly sharp to grab the lifter..

Perhaps the A/I is against using a magnet since they’re so damn difficult to clean off all metal particles?


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Suction air guns are nifty for the job and cost around 30 to 40 bucks. You also use them to bleed your brakes, change tranny or diff fluid, or engine oil in a Merc or other euro car without a drain plug.

They pull lifters right out.

I took the engine building course a few years ago at Mattituck( 2 days) building their Superior engine from scratch. I don't remember why, but the guy there said NEVER use a magnet to remove the lifters..

I’m working on replacing my pushrods with longer ones. Miserable job when it is cold in the hangar. Thick oil makes it worse since the lifters won’t collapse so I have to remove, disassemble, clean out all the oil, reassemble and reinstall each one.

#3 cylinder was the noisy one and while the longer pushrods reduced the valve lash I wish they had reduced it more than it did. One of the engine builders I talked to said even though the dry lash spec is 0.060” - 0.200” anything over about 0.125” will be noisy. Lash on #3 is 0.107” and 0.112.” I was shooting for 0.070” - 0.080” lash. A different engine builder I talked to said since I’m experimental I should install adjustable length pushrods so I could set the lash right at 0.060”...wish I would have listened to him.