New Plugs (Again) . . . questions about the details

[l008com]

Soooooo 2 years ago, I replaced my plugs and wires and the results were great. It went from feeling weak and underpowered, to feeling peppy and like new.

2 years later and it was feeling the same again, so i figured what the hell, I'll just replace the plugs again. Its a very inexpensive job even when you go with high end plugs like I did this time.

Long story short, all the old plugs still looked pretty good. Nothing looked deteriorated or anything. HOWEVER many of the plugs were loose. One was hand loose, I used a socket and my fingers - with no wrench, to remove it.

So does it make sense that the 'weakness' I was feeling was not caused by WORN plugs but by LOOSE plugs that were loosing compression?
If so, how does that happen? Is this a common thing? To people periodically tighten their spark plugs? I've never heard of that before. I still don't regret changing the plugs since its practically the same amount of work to replace them or tighten them. An the truck does feel more powerful again, especially at low throttle low rpm cruising.

Any insight into whats going on here?

 

[Mooseman]

Maybe they weren't torqued down enough last time? If the threads were damaged or hard to screw the plugs in, it may have given a false sense of torque. Might have been worth it in this case to use a spark plug thread chaser to ensure they were clean.

With loose plugs, you basically would have a loss of compression which would equate to loss of power.

 

[Zaab]

They shouldn't be finger loose. When I change plugs on my other car, I torque them down to spec and they stay that tight until next change.

 

[TequilaWarrior]

A quick note... spark plug threads are one of the only exceptions to using an anti-seize compound or lubricant. Spark Plugs should only be installed DRY, into a cool engine, and torqued to spec. Using any sort of anti-seize or lubricant interferes with proper torquing - usually to the "too much" side, but I digress.

 

[l008com]

I replaced them 2 years ago and I torqued them nice and tight. I didn't use any lubricants of any kind. Keep in mind you have to do some crazy acrobatics to install plugs i the V8s, which likely limits your ability to torque them to SOME degree. I guess I should consider tightening my plugs yearly.

 

[TequilaWarrior]

I replaced them 2 years ago and I torqued them nice and tight. I didn't use any lubricants of any kind. Keep in mind you have to do some crazy acrobatics to install plugs i the V8s, which likely limits your ability to torque them to SOME degree. I guess I should consider tightening my plugs yearly.

My favorite vehicles have always had V8s... I know the acrobatics. Nothing like standing on a five gallon bucket on your tip toes to get to the back plug on the passenger side due to 12" of lift on 35s on a full size K truck. I eventually gave up and just sat on the radiator support to do them. I also replaced my plugs and rejetted my carb and retimed everything every season.... the truck made 6 MPG when I bought it and close to 18 MPG when I sold it and made probably double the power.... but that was a 1975 tall-deck, cast iron, sbc that could be tuned sixteen ways from Sunday.

Spark plugs should not need retorqued if torqued properly on installation. What you're experiencing is a little odd. Your plugs look relatively clean, but it appears you might be leaking oil onto the threads... which in and of itself could be the culprit.

 

[l008com]

So next time I tighten my plugs, probably next spring, I'll use a torque gauge just to be safe. So what do I tighten these plugs to?

 

[TequilaWarrior]

To be honest I don't think I've put a torque wrench on a plug since I was in my late teens (30 years ago). I've just always installed them "tight". But one guy's "tight" is another's "aped".

To answer your specific question: 13 lb-ft is the spec I find when I look at the old site...

13 lb-ft is not all that much... I'm confident you're tightening them no less than that.

Installing clean/dry plugs into clean/dry plug holes with proper torque SHOULD keep them in place...