Engine assembly questions

[Mcstealth]

I have a scenario to pass by you engine building types. 

Imagine an IO-360 fully disassembled. New or remaned cases and accessory case. Three new cylinders and one with 150hrs on it. New cam and yellow tagged crank. 

All parts are NOT individually marked which pushrods to which lifter. Which tappets to which...... you get the drift. Nothing is in order. 

My question is, how big a deal is it that the disassembly was sloppy? I've read a litte bit that the "lash" is set by the length of the rods but I've no way of knowing what part came from where. 

My friend has a Stinger tail F-model that I'm trying save from purgatory.  

Any advice?

Thanks, David. 

[MB65E]

Depends on if buying, selling, or just trying to get it running.
You can measure the push rod lengths with the valve lash when the tappets are flat. You won’t have the normal seats and wear patterns on the valve train. 
However, it’s not the end of the world unlike rod caps or other rotating parts.

I think with a little bit of mineral oil at break in it would run in ok. 
 

-Matt

[EricJ]

The Lycoming Direct Drive engine overhaul manual is usually pretty easy to find for free on the internet, and it should have detailed guidance on what needs to stay together and what doesn't.   IIRC things like the actual hydraulic lifter assembly may need to stay together (or not, I don't recall exactly), but it should be spelled out in the manaul.   The pushrods aren't that big of a deal since they're selected during assembly using dry tappet clearance, which is pretty easy to do.   You'll either wind up using all of the pushrods or need to order one or two.

It's not ideal that everything is mixed up, but probably not horribly tragic, either.

[N201MKTurbo]

Just swap your loosest push rods with your tightest, then swap your loosest rocker arms with your tightest. If you cannot get them in range, you will need to buy some new push rods. It takes a couple of hours to put all the pushrod and rockers together, measure them and swap them around.

They usually get tighter when you rebuild an engine because when they overhaul a case they mill a bit off the parting surface and the case gets a bit narrower. 

[Mcstealth]

13 hours ago, MB65E said:

Depends on if buying, selling, or just trying to get it running.
You can measure the push rod lengths with the valve lash when the tappets are flat. You won’t have the normal seats and wear patterns on the valve train. 
However, it’s not the end of the world unlike rod caps or other rotating parts.

I think with a little bit of mineral oil at break in it would run in ok. 
 

-Matt

We want to get the bird flying. 

[201Steve]

envisioning how I’ve read that a factory reman is performed, they strip everything down, check it, throw it in a pile of good or not good, and then an entirely new engine is built of from a pile of random “good parts” I can’t imagine anything must stay together so long as they “check good”. A new pushrod and a new rocker, for example, just met each other on assembly. They haven’t even exchanged phone numbers before they start banging each other. 
 

just my internet guess

[N201MKTurbo]

40 minutes ago, 201Steve said:

envisioning how I’ve read that a factory reman is performed, they strip everything down, check it, throw it in a pile of good or not good, and then an entirely new engine is built of from a pile of random “good parts” I can’t imagine anything must stay together so long as they “check good”. A new pushrod and a new rocker, for example, just met each other on assembly. They haven’t even exchanged phone numbers before they start banging each other. 
 

just my internet guess

AFAIK, you are correct. After the engine is assembled, if you do any cylinder work, you should keep rockers and push rods together so they go back the same way. That is because it is hard to get the lifter inserts out so you can clean all the oil out of them to check the dry lifter clearance. 
 

You can get the inserts out if you remove the SS inserts that the push rod tube seals seat on. You will probably damage the insert getting it out, so you will need a new one. 

[A64Pilot]

Do NOT mismatch lifters and the cam, if you don’t know which hole they came from they need to be reground. New or reground lifters can be put on a used cam

It’s no different than a pushrod car used to be.

Your not supposed to but push rods can be shortened by removing the tip, shortening it and reinstalling it.

On assembly lubriplate the snot out of everything and ideally pre-lube it by putting pressurized oil into a galley before starting.

Difference in breaking in an aircraft engine as opposed to a bike or car is you do not baby the aircraft engine, you run it full rich and hard.

[N201MKTurbo]

1 hour ago, A64Pilot said:

Do NOT mismatch lifters and the cam, if you don’t know which hole they came from they need to be reground. New or reground lifters can be put on a used cam

It’s no different than a pushrod car used to be.

Your not supposed to but push rods can be shortened by removing the tip, shortening it and reinstalling it.

On assembly lubriplate the snot out of everything and ideally pre-lube it by putting pressurized oil into a galley before starting.

Difference in breaking in an aircraft engine as opposed to a bike or car is you do not baby the aircraft engine, you run it full rich and hard.

On Lycomings, you cannot change the lifter bodies without splitting the cases. So, it’s hard to imagine it ever happening.

[A64Pilot]

13 hours ago, N201MKTurbo said:

On Lycomings, you cannot change the lifter bodies without splitting the cases. So, it’s hard to imagine it ever happening.

I know that but apparently what he has is a box or boxes of parts, case already split etc., lifters are out and not segregated as to where they came from, so no way to ensure they go back on the cam lobe they came from.

You may get away with mixing lifters, to be truthful I have never tried as I’ve always heard it will eat the cam, lifters and the cam wear into each other, you can put new lifters on a used cam. but not used ones.

So he either needs to buy new lifters, hopefully DLC ones or have what he has reground and renitrided.

My advice would be to put new DLC lifters in. If a case is split DLC lifters seem to just be logical.

I reread his post I assumed it was for an Experimental, but apparently not, he is going to have to have an A&P involved with this, and of course follow the Lycoming manual.

Edited April 14 by A64Pilot

[N201MKTurbo]

2 hours ago, A64Pilot said:

I know that but apparently what he has is a box or boxes of parts, case already split etc., lifters are out and not segregated as to where they came from, so no way to ensure they go back on the cam lobe they came from.

You may get away with mixing lifters, to be truthful I have never tried as I’ve always heard it will eat the cam, lifters and the cam wear into each other, you can put new lifters on a used cam. but not used ones.

So he either needs to buy new lifters, hopefully DLC ones or have what he has reground and renitrided.

My advice would be to put new DLC lifters in. If a case is split DLC lifters seem to just be logical.

I reread his post I assumed it was for an Experimental, but apparently not, he is going to have to have an A&P involved with this, and of course follow the Lycoming manual.

His original post said there was a new cam. It didn’t say whether the lifter bodies were overhauled. I just assumed they were. Who would put old lifter bodies on a new cam. It seems crazy to split the cases and not get the cam and lifter bodies reground. By aviation standards it is cheap.

[cliffy]

A new cam will require the lifter body faces to be reground (cheaper than buying new lifters)

One can not mix the main  lifter bodies with the valve lash bodies inside the lifter. They are ground together as a set.  If they

are loose in the box you'll need complete new lifter assemblies. 

Lifter bodies inside the lifter can be removed with a piece of safety wire with a very short 90 degree bend on the end, Insert the 90 into the 

lifter and then twist it 90 degrees to be able to pull the valve lash body out of the lifter shell.  You will need to collapse the check valve (get 

the oil out of it ) by using a piece of safety wire into the small end and push in as you squeeze the body together. 

AGAIN- DO NOT MIX UP LIFTER TO LIFTER BODY- EACH BODY HAS TO STAY WITH ITS ORIGINAL OUTER SHELL.

Push rods can be mix and match. Just  as long as the dry clearance is good according to the Lycoming Overhaul Manual-

which you should have, to refer to, as you assemble the engine, This is a MUST!

Everything you ask is jn  the overhaul manual. Get a copy and use it and all things will become clear. 

[Pinecone]

On 4/13/2025 at 8:18 PM, A64Pilot said:

Difference in breaking in an aircraft engine as opposed to a bike or car is you do not baby the aircraft engine, you run it full rich and hard.

Current break in for performance cars and bikes is not babying.

Full throttle runs up to a certain RPM, then next run, slightly higher RPM, repeat until redline.