Spark plugs

Maybe you can enlighten me on the difference? What is the hazard in installing plugs by hand without a piece of hose?

 

That's not an answer

 

Here's the bottom line, go easy. Never force a plug. I've had my aluminum heads for 18 years now on two different short blocks. I use my finger tips to install plugs. If you think you have more "feel" with a rubber hose, that is fine. My plugs always thread in nice in easy. If you have the angle wrong, it won't thread in. Sometimes you need to be patient, just don't force it. As far as not removing plugs when the engine is hot, I think that comes from back in the day when aluminum heads became more widely used. I believe I remember there being a real problem on Corvettes? where GM advised not removing plugs on a hot engine, because they were stripping out the heads. It stands to reason that the expansion rate of an aluminum head and steel plug shell are different, and you might have a problem? I don't have a good reason, on my STREET car to remove a spark plug when my engine is hot. I do understand that you might want to do it on a RACE car at the track. I replace my plugs on a cold engine, and I have never had a problem in 18 years. I have also used the same NGK FR-5 plug for 18 years. They come out light brown when I change them once a year. NGK plugs also feature plated threads. No anti seize compound is required UNLESS you remove a plug and want to reinstall it for whatever reason. Anti seize compound can interfere with heat conduction between the plug and head. Unfortunately, some think if a little is good, more is better.



Regardless, I thread the plugs in by hand and tighten them as much as I can with my fingers. I then tighten them 1/2-3/4 of a turn more with a ratchet and extension. This is for a flat seat, gasket plug in aluminum heads. Tapered seat plugs in iron heads are completely different, 1/16-1/8 of a turn past finger tight.

 

Agreed.