Ford FE loosening spark plugs?

was told today that a couple of plugs in my '59 Galaxie's '68 390 were loose, and might have been the cause of exhaust leak/rough running...
so i grabbed my sockets and ratchet and checked it out... all eight plugs were loose in their holes. some were SEVERAL turns away from snug; some were just "loose" (hard to quantify).... but here's the real killer: it started up and ran even with these plugs loose!

i installed the 390; i KNOW the plugs were tight when i replaced them after the install. will running the engine actually vibrate them loose?
damn FE's... i was gonna say i'd bet it would run with the plug wires off, and i remembered a '65 352 i had that did run with the wires off the p***enger side and the valve cover off. not WELL, but it ran....

 

Wasn't there, or isn't there a tool to cut the carbon off the plug seats? Is this a used engine? Are you torqueing them or just tightening them up? Lippy

 

If I remember right, my father in law had a 390 that blew at least one plug out for about the same reason. There wasn't anything wrong with the threads and I just got a new plug and put it in.

 

Latemodel (junk***) fords spit them out all the time and threads are junk. Count your blessings.

 

the only thing that will cause plugs blowing out or loosing is detonation...even on the late Fords..remember, Nitro Fuel cars have LOTS more cylinder pressure, and they seldom, if tuned right, blow out spark plugs...

 

It seems like I remember years ago where the Fords used the tapered seat, washerless plug. A buddy of mine had some plugs leaking and coming loose. Now on unleaded or a set of clean heads this may not be a problem. But carbon and **** on the plug seats in the heads was the issue. I remember he had a tool that would screw in and clean the plug seat of carbon. I must be getting old.This was a 352 I believe. Lippy

 

I was going to say the same thing. Seats dirty could be your culprit.

Also if the washers have gone flat from being removed too many times. Back when they used to clean and regap plugs at the service station you could buy new washers and a reputable mechanic would change them when he cleaned the plugs.

 

of all the FE's i've run, this is the only one that's done this to me. had a plug break off the threaded shank in the head of a POS 400m Ford.... i hate them things.