Spark plug install question

[mkrakoff]

 Changed out all 8 plugs for fine wires the other day and everything went very well (haven’t flown with them yet) BUT I’m wondering if I made a rookie mistake. 
 

Swapped out the top 4 and did a ground run for a few minutes before removing the bottom cowling and removing/installing the bottom 4. How critical is it that the engine was warm and not cold? It wasn’t hot, as in just came in from a flight, but it sure wasn’t cold. I was able to handle the removed plugs without frying my fingers. My thoughts after the fact is that it’s possible they are a bit over-torqued from the Aluminum head cooling onto a cooler plug after I properly torqued to 35ftlbs. Although another part of me says that the plug probably warmed up pretty quickly once in contact with the cylinder. 
 

Thoughts? Do we ever see mechanics changing plugs on warm engines? How critical is the “cold” engine for plug installs.

[N201MKTurbo]

Don’t worry about it. 
 

Let’s try to justify this a bit. The copper washer will compress before you pull the helicoil.

Probably B.S. but it sounds good.

I’ve taken out and replaced spark plugs from blazing hot engines and stone cold engines. Never a problem, other than burned fingers.

Edited January 4, 2022 by N201MKTurbo

[mkrakoff]

Thanks, I’m wondering if I’m overthinking it a bit. Ideal world all materials are the exact same temp at install but when you add up all the variables it’s probably not the end of the world. In actuality I’m trying to justify not pulling the cowlings and the bottom plugs in the 28F temps tomorrow before my flight  

[PT20J]

You’re overthinking it 

Spark plug torque isn’t all that critical. A lot of charts show 30-35 ft-lb for Lycoming and 25-30 for Continental and P&W.

Just don’t forget the gaskets. Someone did that on a plug on the museum DC-3 and it was a bear to get out because it allows deposits to form on the couple of threads that protrude into the combustion chamber without the gasket. 

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