So what's the deal with spark plug washers?

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cruiser

cruiser

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MOPAR faithful: I know this has been discussed before, but could someone please explain to me why you're supposed to remove the washers from the spark plugs that you install in your slant six? I have a 74 Duster. The washers are there and the motor runs fine. I torque them to 30 foot pounds just like the service manual says. You cannot remove the washers from the NGK plugs that I use. What kind of washerless plugs do you use in your mid-1970s slant six?
 
cruiser said:
MOPAR faithful: I know this has been discussed before, but could someone please explain to me why you're supposed to remove the washers from the spark plugs that you install in your slant six? I have a 74 Duster. The washers are there and the motor runs fine. I torque them to 30 foot pounds just like the service manual says. You cannot remove the washers from the NGK plugs that I use. What kind of washerless plugs do you use in your mid-1970s slant six?
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I've never seen a plug I couldn't remove the washer from. As long as you have the head with the metal drool tubes in the spark plug access holes, you remove the washers. You do this because the drool tubes act as the washer for the plug. Having both and the plugs will not seal properly. You can take a small pair of dykes and hold the washers a little crooked and snip them right off.
 
The deal with the washers depends on which head you have. And all slant heads will fit any block, so you have to check - lots gets changed over time. If you have drool-tube heads (the plugs go INSIDE the head, in a tube) you need to remove the washers. If it's a peanut head (the plugs screw into the outside of the head and are visible) you leave the washers intact. If you need to take the washers off for a drool-tube head, grab them with a pair of needle nose pliers and twist them till they break. Easy Peasy.
 
Maybe I'm thinking about this too much, but won't it affect the performance of the spark plug if you remove its washer? Wouldn't the NGK factory say that their plugs are designed to work with a washer and removing it would affect the way it performs?
 
They seal fine.
All you're doing is spacing the plug that much further out. Does it hurt, no.
I built my first engine as a teenager, a 225. I cam'd it, milled and ported the head, full length header...painted it chry industrial red
I NEVER REMOVED THE PLUG WASHERS.
Thing ran like a dream and always left my passengers wanting one, for the novelty I'm sure...which is what building a slant up is all about...just foolin round makin people dance with a little gun.
They make torquing spark plugs 'idiot proof' so you know ...as it crushes snug and stops...that's it!
 
Plugs are another emotional subject... everyone has their idea of what is best and what is worst. I run ZFR5N (#3459) in mine with excellent results. I do remove the washers too, as I have the drool tube heads.
 
"It might be" that improperly having/ nothaving washers will affect the heat range characteristics. These are determined by the heat range/ construction of the plug as well as the HEAT SINK EFFECT of the head in which they are installed
 
If hooha up there in post #6 says you can run with the washers, then run them. I always take them off, but it may not make a difference. The drool tubes are awfully thin anyway.
 
Drool tubes do not always equate to no washers: you can tell if head has been changed by looking at spark plug counterbore (63+) or lack of on early 60-62. No counterbore/flat on early head means it still takes a gasket on top of the flat ended drool tube.

"The factory TSB discussing the cylinder head changes for '63 and the importance of using the gaskets in '60-'62 heads and not using the gaskets in '63-up heads..."
@slantsixdan Dan.

_________________
 
actually, they are not washers. they are compression rings. they compress as you tighten the plug to create a seal between the plug and the head. and, they have a specific way they go on the plug.
 
slantsixdan said:
See here and here, then decide whether you'd rather believe the engineers who spent a whole lot of time and effort researching and developing this exact aspect of these exact engines, with all kinds of test equipment and facilities…or if you'd prefer to believe some guy who built a motor when he was a teenager and didn't study the matter at all, let alone scientifically, just left the washers on the plugs and he's real sure it ran totally great.

Your car, your engine, your choice.
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You may be right you pompous son of a ***** but I can show you LOTS of things that were designed by engineers who should have known, and spent lots of time doing so, and "whatever it was" didn't operate correctly, failed often, and in some cases, caused injury or death.
 
cruiser said:
MOPAR faithful: I know this has been discussed before, but could someone please explain to me why you're supposed to remove the washers from the spark plugs that you install in your slant six? I have a 74 Duster. The washers are there and the motor runs fine. I torque them to 30 foot pounds just like the service manual says. You cannot remove the washers from the NGK plugs that I use. What kind of washerless plugs do you use in your mid-1970s slant six?
Click to expand...

Never had a slant , but in the 426 hemi`s , the washers would eat up the spark plug seal tubes . On a slant I think they maybe called something else , but think they are still alum. .
The alum. tubes will seal the plugs/combustion chamber .
 
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