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]

  On 3/18/2025 at 4:18 AM, 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

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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]

  On 3/18/2025 at 10:25 PM, 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

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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.